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Surface mining and reclamation activities can substantially affect the soil physical properties that mediate water movement and root growth, impeding the re-establishment of native vegetation and ecosystem function. Deep ripping is a promising approach to mitigate compaction using long shanks dragged through the soil, but little is known about its effectiveness in fine-textured glacial parent material. In five reclaimed surface mines and four reference forests on glacial parent material, we measured soil bulk density and saturated hydraulic conductivity. Two mine sites were subsequently subjected to deep ripping in a grid pattern and soil properties were remeasured within and outside of the rips. Before ripping, near-surface bulk density was higher and saturated hydraulic conductivity was lower at the reclaimed mines than the reference forests, and mine soils deeper than 20 cm were often denser than ideal for plant growth (>1.4 g cm−3). Ripping increased variability in bulk density and saturated hydraulic conductivity, with the intersection of perpendicular rips becoming denser than pre-rip conditions in the top 5 cm. Below the surface, soils in the rips were generally less dense than pre-rip conditions, and soil piping was observed within some rips. Between the rips, bulk density decreased in the top 5 cm, but remained constant or increased relative to pre-rip conditions at greater depths. These results emphasize the importance of fine-scale, spatially explicit sampling when assessing the effects of mine reclamation and ripping. Our data support strategies of planting trees within rip intersections, though cast doubt on the potential for root expansion into areas between rips.

In a soilless culture (perlite substrate), root restriction cannot only reduce production costs but also improve fruit quality. Therefore, this study used different levels of root restriction [T1: 0.5 L, T2: 4 L, nonrestriction treatment (CK): 35 L] on tomatoes to explore their impact on quality. Results showed that total soluble solids (TSS), glucose, fructose, and sucrose contents were increased, whereas L-tryptophan, L-tyrosine, and titratable acidity were decreased under two restriction treatments. Meanwhile, root restriction also promoted the accumulation of phenylalanine and proline. For lycopene and flavonoid biosynthesis (prunin, naringin, naringenin), the restriction groups were significantly higher than those in the control group. Overall, T1 and T2 treatment had a better effect than CK treatment. This study provided an idea for improving substrate use efficiency and tomato quality. [ABSTRACT FROM AUTHOR]

Root restriction is a physical and ecological cultivation mode which restricts plant roots into a limited container to regulate vegetative and reproduction growth by reshaping root architecture. However, little is known about related molecular mechanisms. To uncover the root-related regulatory network of endogenous RNAs under root restriction cultivation (referred to RR), transcriptome-wide analyses of mRNAs, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) involved in root development were performed. During root development, RR treatment had a positive effect on root weight, typically, young roots were significantly higher than conventional cultivation (referred to NR) treatment, suggesting that root architecture reconstruction under RR was attributed to the vigorous induction into lateral roots. Furthermore, a total of 26,588 mRNAs, 1971 lncRNAs, and 2615 circRNAs were identified in root of annual "Muscat Hamburg" grapevine by the transcriptomic analyses. The expression profile of mRNAs, lncRNAs and circRNA were further confirmed by the quantitative real-time PCR (RT-qPCR). Gene ontology enrichment analysis showed that a majority of the differentially expressed mRNAs, lncRNAs and circRNAs were enriched into the categories of cellular process, metabolic process, cell part, binding, and catalytic activity. In addition, the regulatory network of endogenous RNAs was then constructed by the prediction of lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA network, implying that these RNAs play significant regulatory roles for root architecture shaping in response to root restriction. Our results, for the first time, the regulatory network of competitive endogenous RNAs (ceRNAs) functions of lncRNA and circRNA was integrated, and a basis for studying the potential functions of non-coding RNAs (ncRNAs) during root development of grapevine was provided. [ABSTRACT FROM AUTHOR]

The root system is essential for the stable growth of plants. Roots help anchor plants in the soil and play a crucial role in water uptake, mineral nutrient absorption and endogenous phytohormone formation. Root-restriction (RR) cultivation, a powerful technique, confines plant roots to a specific soil space. In the present study, roots of one-year-old “Muscat Hamburg” grapevine under RR and control (nR) treatments harvested at 70 and 125 days after planting were used for transcriptome sequencing, and in total, 2031 (nR7 vs. nR12), 1445 (RR7 vs. RR12), 1532 (nR7 vs. RR7), and 2799 (nR12 vs. RR12) differentially expressed genes (DEGs) were identified. Gene Ontology (GO) enrichment analysis demonstrated that there were several genes involved in the response to different phytohormones, including abscisic acid (ABA), auxin (IAA), ethylene (ETH), gibberellins (GAs), and cytokinins (CTKs). Among them, multiple genes, such as PIN2 and ERF113, are involved in regulating vital plant movements by various phytohormone pathways. Moreover, following RR cultivation, DEGs were enriched in the biological processes of plant-type secondary cell wall biosynthesis, the defense response, programmed cell death involved in cell development, and the oxalate metabolic process. Furthermore, through a combined analysis of the transcriptome and previously published microRNA (miRNA) sequencing results, we found that multiple differentially expressed miRNAs (DEMs) and DEG combinations in different comparison groups exhibited opposite trends, indicating that the expression levels of miRNAs and their target genes were negatively correlated. Furthermore, RR treatment indeed significantly increased the ABA content at 125 days after planting and significantly decreased the IAA content at 70 days after planting. Under RR cultivation, most ABA biosynthesis-related genes were upregulated, while most IAA biosynthesis-related genes were downregulated. These findings lay a solid foundation for further establishing the network through which miRNAs regulate grapevine root development through target genes and for further exploring the molecular mechanism through which endogenous ABA and IAA regulate root architecture development in grapevine. [ABSTRACT FROM AUTHOR]

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In most grapevine planting regions, especially in south of China, plenty of rainfall and high water level underground are the characteristic of the area, a series of problem during fruit ripening easily caused poor color quality. Thereby affecting fruit quality, yield and economic benefits. The accumulation of anthocyanin is regulated by transcriptional regulatory factor and a series of cultivation measures, root restriction can make plants in the environment of stress and stress relief, root restriction induced the higher expression of VvMYB15 and VvWRKY40 , and consistent with anthocyanin accumulation. Whether and how root restriction-inducible VvMYB15 and VvWRKY40 transcription factor regulate anthocyanin synthesis in grape berry is still unclear. In this study, we identified that the transient overexpression of VvMYB15 and VvWRKY40 alone or both in strawberry fruits and grape berries can promote anthocyanin accumulation and increase the expression level of anthocyanin biosynthetic genes, indicating VvMYB15 and VvWRKY40 play a positive regulator of anthocyanin biosynthesis. Furthermore, we confirmed that both VvMYB15 and VvWRKY40 specifically bind to the promoter region of VvF3 ′ 5 ′ H and VvUFGT , and the expression of VvF3 ′ 5 ′ H and VvUFGT is further activated through the heterodimer formation between VvMYB15 and VvWRKY40. Finally, we confirmed that VvMYB15 promoted anthocyanin accumulation by interacting with VvWRKY40 in grape berries, our findings provide insights into a mechanism involving the synergistic regulation of root restriction-dependent coloration and biosynthesis via a VvMYB15 and VvWRKY40 alone or both in grape berries. [ABSTRACT FROM AUTHOR]

In most grapevine planting regions, especially in south of China, plenty of rainfall and high water level underground are the characteristic of the area, a series of problem during fruit ripening easily caused poor color quality. Thereby affecting fruit quality, yield and economic benefits. The accumulation of anthocyanin is regulated by transcriptional regulatory factor and a series of cultivation measures, root restriction can make plants in the environment of stress and stress relief, root restriction induced the higher expression of VvMYB15 and VvWRKY40, and consistent with anthocyanin accumulation. Whether and how root restriction-inducible VvMYB15 and VvWRKY40 transcription factor regulate anthocyanin synthesis in grape berry is still unclear. In this study, we identified that the transient overexpression of VvMYB15 and VvWRKY40 alone or both in strawberry fruits and grape berries can promote anthocyanin accumulation and increase the expression level of anthocyanin biosynthetic genes, indicating VvMYB15 and VvWRKY40 play a positive regulator of anthocyanin biosynthesis. Furthermore, we confirmed that both VvMYB15 and VvWRKY40 specifically bind to the promoter region of VvF3′5′H and VvUFGT, and the expression of VvF3′5′H and VvUFGT is further activated through the heterodimer formation between VvMYB15 and VvWRKY40. Finally, we confirmed that VvMYB15 promoted anthocyanin accumulation by interacting with VvWRKY40 in grape berries, our findings provide insights into a mechanism involving the synergistic regulation of root restriction-dependent coloration and biosynthesis via a VvMYB15 and VvWRKY40 alone or both in grape berries.

Soilless culture systems are currently one of the fastest-growing sectors in horticulture. The plant roots are confined into a specific rootzone and are exposed to environmental changes and cultivation factors. The recent scientific evidence regarding the effects of several environmental and cultivation factors on the morphology, architecture, and performance of the root system of plants grown in SCS are the objectives of this study. The effect of root restriction, nutrient solution, irrigation frequency, rootzone temperature, oxygenation, vapour pressure deficit, lighting, rootzone pH, root exudates, CO2, and beneficiary microorganisms on the functionality and performance of the root system are discussed. Overall, the main results of this review demonstrate that researchers have carried out great efforts in innovation to optimize SCS water and nutrients supply, proper temperature, and oxygen levels at the rootzone and effective plant-beneficiary microorganisms, while contributing to plant yields. Finally, this review analyses the new trends based on emerging technologies and various tools that might be exploited in a smart agriculture approach to improve root management in soilless cropping while procuring a deeper understanding of plant root-shoot communication. [ABSTRACT FROM AUTHOR]

Root restriction is a physical and ecological cultivation mode which restricts plant roots into a limited container to regulate vegetative and reproduction growth by reshaping root architecture. However, little is known about related molecular mechanisms. To uncover the root-related regulatory network of endogenous RNAs under root restriction cultivation (referred to RR), transcriptome-wide analyses of mRNAs, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) involved in root development were performed. During root development, RR treatment had a positive effect on root weight, typically, young roots were significantly higher than conventional cultivation (referred to NR) treatment, suggesting that root architecture reconstruction under RR was attributed to the vigorous induction into lateral roots. Furthermore, a total of 26,588 mRNAs, 1971 lncRNAs, and 2615 circRNAs were identified in root of annual “Muscat Hamburg” grapevine by the transcriptomic analyses. The expression profile of mRNAs, lncRNAs and circRNA were further confirmed by the quantitative real-time PCR (RT-qPCR). Gene ontology enrichment analysis showed that a majority of the differentially expressed mRNAs, lncRNAs and circRNAs were enriched into the categories of cellular process, metabolic process, cell part, binding, and catalytic activity. In addition, the regulatory network of endogenous RNAs was then constructed by the prediction of lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA network, implying that these RNAs play significant regulatory roles for root architecture shaping in response to root restriction. Our results, for the first time, the regulatory network of competitive endogenous RNAs (ceRNAs) functions of lncRNA and circRNA was integrated, and a basis for studying the potential functions of non-coding RNAs (ncRNAs) during root development of grapevine was provided.

Although vegetable nursery growers decide on plug sizes based on the types, production time and schedule of the crops to grow, they usually choose individual small cell sizes because these allow short plant-raising periods and reduced costs. However, larger plugs produce a finished plant after transplant in a shorter period of time than smaller plugs. Nursery growers end the propagation period when roots take up the plug cell and plantlets can be removed from the plug tray without damage. Thus, this study aimed to investigate the effect of three plug-cell sizes and a single BAP application (100 mg L-1) on the shoot and root growth and time to transplant of different lettuce genotypes. Nursery decreased as plug cell volume increased and with the single BAP spray. A novelty result was that the transplant dates were assigned when the marginal root dry weight accumulation decreased, i.e., based on objective rather than on subjective observations. The significant leaf area and dry weight accumulation found could be explained by growth parameters such as the rate of leaf appearance, the relative rate of leaf area expansion, the relative growth rate, the net assimilation rate and the partition coefficient from root: shoot allometries. Highlights Root restriction due to small plugs in transplant trays delay lettuce transplant. Exogenous cytokinin (BAP) overcame root restriction and decreased time to transplant. Time to transplant can be addressed on an objective basis: it were assigned when the marginal root dry weight accumulation decreased.

• Mine reclamation compacted glacial parent materials, impeding reforestation. • Deep ripping lowers soil bulk density within rips, below the surface. • Deep ripping increases variability in hydraulic conductivity and creates pipes. • Deep ripping may create soils that better support tree growth within, but not outside, the rips. Surface mining and reclamation activities can substantially affect the soil physical properties that mediate water movement and root growth, impeding the re-establishment of native vegetation and ecosystem function. Deep ripping is a promising approach to mitigate compaction using long shanks dragged through the soil, but little is known about its effectiveness in fine-textured glacial parent material. In five reclaimed surface mines and four reference forests on glacial parent material, we measured soil bulk density and saturated hydraulic conductivity. Two mine sites were subsequently subjected to deep ripping in a grid pattern and soil properties were remeasured within and outside of the rips. Before ripping, near-surface bulk density was higher and saturated hydraulic conductivity was lower at the reclaimed mines than the reference forests, and mine soils deeper than 20 cm were often denser than ideal for plant growth (>1.4 g cm−3). Ripping increased variability in bulk density and saturated hydraulic conductivity, with the intersection of perpendicular rips becoming denser than pre-rip conditions in the top 5 cm. Below the surface, soils in the rips were generally less dense than pre-rip conditions, and soil piping was observed within some rips. Between the rips, bulk density decreased in the top 5 cm, but remained constant or increased relative to pre-rip conditions at greater depths. These results emphasize the importance of fine-scale, spatially explicit sampling when assessing the effects of mine reclamation and ripping. Our data support strategies of planting trees within rip intersections, though cast doubt on the potential for root expansion into areas between rips. [ABSTRACT FROM AUTHOR]

The low-node pinching order at a high-density plant cultivation system (LN&HD) is now widely adopted for increasing tomato yield and fruit quality. The LN&HD cultivation period spans 70-120 days, employs the use of a small amount of substrate (low substrate volume), and plants are usually topped between the first and the fourth truss. Using a small amount of substrate in cultivation induces root restriction. Increasing the extent of root restriction in small pots has been adopted for increasing the fruit quality of tomato in some advanced countries. However, improving fruit quality at the expense of yield becomes a major drawback for adopting the LN&HD in Ghana. The LN&HD was introduced into Ghana mainly to increase tomato yield sustainably at a cost-effective level. This study aimed to manipulate or reduce the extent of root restriction to increase tomato yield. Information related to manipulating or reducing the extent of root restriction has not been extensively reported. Thus, an experiment was conducted (between 21 April 2019 and 11 August 2019) in the greenhouse of the University of Ghana Forest and Horticultural Research Centre, Kade-Ghana. Plants of two tomato cultivars (Jaguar and Momotaro York) were subjected to four root restriction conditions. The extent of root restriction were (1) complete root restriction in a 1.0 L volume capacity pot, (2) complete root restriction in a 1.5 L volume capacity pot, (3) partial root restriction in Rockwool-like cultivation, otherwise referred to as Cocowool, and (4) No root restriction in a trough containing 1.5 L of the substrate. The experiment was laid out in a 2 x 4 factorial in a randomized complete block. Results showed that partial root restriction in Cocowool and unrestricted roots in the trough produced the highest tomato yield and total dry matter compared to the plants that received complete root restrictions in the 1.0 and 1.5 L pots. However, the tomato's total soluble solids increased with a complete root restriction in the 1.0 L pot. Reducing the extent of root restriction increased the yield and total dry matter of tomato. With the LN&HD, a small amount of substrate could be used (at a reduced cost) with a partial root restriction to increase the yield of tropical tomato cultivars grown in Ghana. [ABSTRACT FROM AUTHOR]

Although vegetable nursery growers decide on plug sizes based on the types, production time and schedule of the crops to grow, they usually choose individual small cell sizes because these allow short plant-raising periods and reduced costs. However, larger plugs produce a finished plant after transplant in a shorter period of time than smaller plugs. Nursery growers end the propagation period when roots take up the plug cell and plantlets can be removed from the plug tray without damage. Thus, this study aimed to investigate the effect of three plug-cell sizes and a single BAP application (100 mg L-1) on the shoot and root growth and time to transplant of different lettuce genotypes. Nursery decreased as plug cell volume increased and with the single BAP spray. A novelty result was that the transplant dates were assigned when the marginal root dry weight accumulation decreased, i.e., based on objective rather than on subjective observations. The significant leaf area and dry weight accumulation found could be explained by growth parameters such as the rate of leaf appearance, the relative rate of leaf area expansion, the relative growth rate, the net assimilation rate and the partition coefficient from root: shoot allometries. [ABSTRACT FROM AUTHOR]

Root restriction (RR) has been reported to enhance grape berry quality in diverse aspects of grape life. In this study, RR-induced increases in the main primary metabolites in the grape berry and the expression of their related genes were studied at different developmental stages. Mainly the transcriptomic and metabolomic level were analyzed using ‘Summer Black’ grape berry as a material. The main results were as follows: A total of 11 transcripts involved in the primary metabolic pathways were significantly changed by the RR treatment. Metabolites such as sugars, organic acids, amino acids, starch, pectin, and cellulose were qualitatively and quantitatively analyzed along with their metabolic pathways. Sucrose synthase (VIT_07s0005g00750, VIT_11s0016g00470) and sucrose phosphate synthase (VIT_18s0089g00410) were inferred to play critical roles in the accumulation of starch, sucrose, glucose, and fructose, which was induced by the RR treatment. RR treatment also promoted the malic acid and tartaric acid accumulation in the young berry. In addition, the grape berries after the RR treatment tended to have lower pectin and cellulose content.

Soilless culture systems are currently one of the fastest-growing sectors in horticulture. The plant roots are confined into a specific rootzone and are exposed to environmental changes and cultivation factors. The recent scientific evidence regarding the effects of several environmental and cultivation factors on the morphology, architecture, and performance of the root system of plants grown in SCS are the objectives of this study. The effect of root restriction, nutrient solution, irrigation frequency, rootzone temperature, oxygenation, vapour pressure deficit, lighting, rootzone pH, root exudates, CO2, and beneficiary microorganisms on the functionality and performance of the root system are discussed. Overall, the main results of this review demonstrate that researchers have carried out great efforts in innovation to optimize SCS water and nutrients supply, proper temperature, and oxygen levels at the rootzone and effective plant–beneficiary microorganisms, while contributing to plant yields. Finally, this review analyses the new trends based on emerging technologies and various tools that might be exploited in a smart agriculture approach to improve root management in soilless cropping while procuring a deeper understanding of plant root–shoot communication.

This study investigated the effects of root-restriction cultivation on the root architecture, endogenous strigolactone (SL) content, and SL-related genes expression in grapevine (Vitis vinifera L.). In addition, we clarified the effects of synthetic SL analog GR24 application on grapevine roots to explore the role of SLs in their development. The results showed that the root architecture changed significantly under root-restriction cultivation. At 40 days after transplantation (DAT), the contents of two types of SLs in roots under root restriction were both significantly lower than that in roots of the control. SL content was significantly positively correlated with the expression levels of VvCCD8 and VvD27, indicating that they play vital roles in SLs synthesis. After GR24 treatment for 20 days, the root length was significantly shorter than in the control. A low concentration (0.1 μM) of GR24 significantly reduced the root diameter and increased the fine-root density, while a high concentration (10 μM) of GR24 significantly reduced the lateral root (LR) length and increased the LR density. Concomitantly, GR24 (0.1 μM) reduced endogenous SL content. After GR24 treatment for 5 days, the total content of two tested SLs was highly positively correlated with the expression levels of VvDAD2, whereas it was highly negatively correlated with VvSMAXL4 at 20 days after GR24 treatment. This study helps to clarify the internal mechanism of root-restriction cultivation affecting the changes in grapevine root architecture, as well as further explore the important role of SLs in the growth of grapevine roots in response to root-restriction treatment.

The compositions and contents of metabolites in the pulp tissue play critical roles in the fruit quality for table grape. In this study, the effects of root restriction (RR) on the primary and secondary metabolites of pulp tissue at five developmental stages were studied at the metabolomics level, using “Red Alexandria” grape berry (Vitis vinifera L.) as materials. The main results were as follows: 283 metabolites were annotated by using ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS); 28 and 16 primary metabolites contents were increased and decreased, and 11 and 19 secondary metabolites contents were increased and decreased, respectively, along the berry development; RR significantly decreased 12 metabolites (four amino acids and derivatives, three organic acids, four flavonoids and one other compound) contents, and improved 40 metabolites (22 amino acids and derivatives, six nucleotides, four carbohydrates, four cofactors, three cinnamic acids and one other compound) accumulation at the different developmental stages. Altogether, our study would be helpful to increase our understanding of grape berry’s responses to RR stress.

The low-node pinching order at a high-density plant cultivation system (LN&HD) is now widely adopted for increasing tomato yield and fruit quality. The LN&HD cultivation period spans 70–120 days, employs the use of a small amount of substrate (low substrate volume), and plants are usually topped between the first and the fourth truss. Using a small amount of substrate in cultivation induces root restriction. Increasing the extent of root restriction in small pots has been adopted for increasing the fruit quality of tomato in some advanced countries. However, improving fruit quality at the expense of yield becomes a major drawback for adopting the LN&HD in Ghana. The LN&HD was introduced into Ghana mainly to increase tomato yield sustainably at a cost-effective level. This study aimed to manipulate or reduce the extent of root restriction to increase tomato yield. Information related to manipulating or reducing the extent of root restriction has not been extensively reported. Thus, an experiment was conducted (between 21 April 2019 and 11 August 2019) in the greenhouse of the University of Ghana Forest and Horticultural Research Centre, Kade-Ghana. Plants of two tomato cultivars (Jaguar and Momotaro York) were subjected to four root restriction conditions. The extent of root restriction were (1) complete root restriction in a 1.0 L volume capacity pot, (2) complete root restriction in a 1.5 L volume capacity pot, (3) partial root restriction in Rockwool-like cultivation, otherwise referred to as Cocowool, and (4) No root restriction in a trough containing 1.5 L of the substrate. The experiment was laid out in a 2 x 4 factorial in a randomized complete block. Results showed that partial root restriction in Cocowool and unrestricted roots in the trough produced the highest tomato yield and total dry matter compared to the plants that received complete root restrictions in the 1.0 and 1.5 L pots. However, the tomato’s total soluble solids increased with a complete root restriction in the 1.0 L pot. Reducing the extent of root restriction increased the yield and total dry matter of tomato. With the LN&HD, a small amount of substrate could be used (at a reduced cost) with a partial root restriction to increase the yield of tropical tomato cultivars grown in Ghana.

The central-north of Brazil is a region with strong presence of concrectionary soil, whose supposed disadvantages from the agronomic point of view, do not prevent their use in agriculture. However, more in-depth information about the behavior of crops of agricultural interest cultivated in this type of soil is few. Due to the observation of agricultural stands in this type of soil, it was hypothesized that plinthite ironstones concretions negatively interfere in the development of crops of agro-economic interest. The objective was to verify the growth and development of soybean cultivated in soil with the presence and absence of plinthite ironstones. Concretionary Petric Plinthosol were collected in the 0-0,20 m layer and part of the soil was sieved so that concretions larger than 3.10 mm in diameter were removed, thus leaving two treatments, soil with and without plinthite ironstones. Morphological evaluations were performed during their phenological phase. Soybean grown in soil without ironstones showed higher growth at 32 and 48 DAE and more leaflets when compared to soy crop grown in soil with ironstones. As for dry matter, soybean grown in soil without ironstones showed more values for aerial, root and total mass as well for aerial root rate when compared to soybean grown in soil with ironstones. Plinthite ironstones interfere with the growth and/or vegetative development of soybeans. Soybean has less vegetative development when grown in soil with plinthite ironstone concretions. [ABSTRACT FROM AUTHOR]

Root restriction cultivation (RRC) can influence plant root architecture, but its root phenotypic changes and molecular mechanisms are still unknown. In this study, phenotype observations of grapevine root under RRC and control cultivation (nRC) at 12 time points were conducted, and the root phenotype showed an increase of adventitious and lateral root numbers and root tip degeneration after RRC cultivation from 70 days after planting (DAP). The 70 and 125 DAP sampling of two different cultivations, named nR70, RR70, nR125, and RR125, were selected for small RNA sequencing. A total of 153 known miRNAs and 119 predicted novel miRNAs were obtained. Furthermore, BLAST was used to predict the novel miRNAs with miRBase databases using the default parameters; 96 of the 119 predicted novel miRNAs were similar to other species, and the remaining 23 grapevine-specific novel miRNAs were obtained. There were 26, 33, 26, and 32 miRNAs that were differentially expressed in different comparison groups (RR70 vs. nR70, RR125 vs. nR125, nR125 vs. nR70 and RR125 vs. RR70). Target genes prediction of differentially expressed miRNAs was annotated on a variety of biological processes, and 24 participated in root development. Moreover, multiple miRNAs were found to jointly regulate lateral root development under root restriction conditions. The miRNA expression pattern comparison between RRC and nRC may provide a framework for the future analysis of miRNAs associated with root development in grapevine.

To decipher the relationship between the inhibited shoot growth and expression pattern of key enzymes in nitrogen metabolism under root restriction, the effects of root restriction on diurnal variation of expression of nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS1-1, GS1-2, GS2) and glutamate synthase (Fd-GOGAT, NADH-GOGAT) genes and nitrogen levels were evaluated in two-year-old Jumeigui grapevines (Vitis vinifera L.×Vitis labrusca L.) when significant differences in shoot growth were observed between treatments at expansion stage (22 days after anthesis). Grapevines were planted in root-restricting pits as root restriction and in an unrestricted field as the control. Results showed that root restriction significantly reduced shoot growth, but promoted the growth of white roots and fibrous brown roots and improved the fruit quality. (NO3−+NO2−)-N concentration in all plant parts, NH4+-N concentration in white roots and total N concentration in leaves and brown roots were significantly reduced under root restriction. Gene expression analysis revealed that mRNA levels of genes related to the GS1/NADH-GOGAT pathway were lower in root-restricted than in control petioles, whereas genes involved in the GS2/Fd-GOGAT pathway were up-regulated under root restriction. Root restriction also resulted in down-regulation of genes involved in nitrogen metabolism in leaves, especially at 10:00, while transcript levels of all these genes were enhanced in root-restricted white and brown roots at most time points. This organ-dependent response contributed to the alteration in NO3− reduction and NH4+ assimilation under root restriction, leading to less NO3− transported from roots and then assimilated in root-restricted leaves. Therefore, this study implied that shoot growth inhibition in grapevines under root restriction is closely associated with down-regulation of gene expression in nitrogen metabolism in leaves.

This research aimed to comparatively evaluate the influences of root restriction (RR) cultivation and traditional cultivation (RC) on grape berry skin metabolomics using a non-targeted metabolomics method. Two-hundred-and-ninety-one metabolites were annotated and the kinetics analyses showed that berry skin metabolome is stage- and cultivation-dependent. Our results showed that RR influences significantly the metabolomes of berry skin tissues, particularly on secondary metabolism, and that this effect is more obvious at pre-veraison stage, which was evidenced by the early and fast metabolic shift from primary to secondary metabolism. Altogether, this study provided an insight into metabolic adaptation of berry skin to RR stress and expanded general understanding of berry development.

Root restriction improved berry quality by being involved in diverse aspects of grapevine life. However, the molecular mechanism driving this process is not understood very well. In this study, the 'Summer Black' grape berry (Vitis vinifera x V. labrusca) under root restriction was investigated, which showed an increase of total soluble solids (TSS), color index of red grapes (CIRG) value, anthocyanins accumulation, total phenolics and total procyanidins contents during berry development compared with those in control berries. The transcriptomic changes induced by root restriction in 'Summer Black' grape over the course of berry development were analyzed by RNA-Seq method. A total of 29,971 genes were generated in 'Summer Black' grape berry during development, among which, 1606 genes were significantly responded to root restriction. Furthermore, 1264, 313, 141, 246 and 19 sequences were significantly changed at S1, S2, S3, S4 and S5 sample points, respectively. The gene (VIT_04s0023g02290) predicted as a salicylate O-methyltransferase was differentially expressed in all developmental stages. Gene Ontology (GO) enrichment showed that response to organic nitrogen, response to endogenous stimulus, flavonoid metabolic process, phenylpropanoid biosynthetic process and cell wall macromolecule metabolic process were the main significant differential categories. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment revealed plant-pathogen interaction, plant hormone signal transduction, flavone and flavonol biosynthesis, flavonoid biosynthesis and glucosinolate biosynthesis were the main significant differential pathways. The results of the present study provided a genetic base for the understanding of grape berry fruit quality improvement under root restriction. [ABSTRACT FROM AUTHOR]

Mesmo tendo-se avançando nas técnicas de produção de mudas, ainda existem muitos problemas a serem solucionados, principalmente no que se refere ao desenvolvimento do sistema radicular das mudas, em função das características dos recipientes utilizados. O objetivo do trabalho foi determinar o efeito do tamanho do recipiente e do tempo de cultivo da planta na produção de mudas de Copernicia hospitaMartius. Sementes extraídas de frutos em estádio visual de maturação foram pré-germinadas e semeadas em sacos plásticos de 20 x 30, 28 x 40 e 40 x 60 cm, contendo como substrato a mistura de arisco + areia vermelha + esterco bovino curtido (2:1:1). Após a semeadura, osrecipientes foram mantidos por três, seis ou nove meses em pleno sol. Nenhum dos recipientes analisados, durante seus respectivos períodos de cultivo, influenciou as variáveis de crescimento utilizadas na avaliação das respostas da planta. O tamanho dos recipientes não influenciou na formação das mudas de C. hospita; contudo, em função da economia e praticidade, recomenda-se a utilização do recipiente com dimensões de 20 x 30 cm. O tempo de cultivo, de nove meses, forma mudas mais vigorosas.Even though advances have been made in the techniques of seedlingproduction, there are still many problems to be solved, especially with regard to the development of the root system of seedlings, depending on the containers used. The objective of this study was to determine the effect of recipient size and the plant cultivationtime in the production of C. hospita seedlings. Seeds of carnauba (Copernicia hospita Martius) obtained from mature fruit, were pre-germinated and sown in plastic 20 x 30, 28 x 40 and 40 x 60 cm bags, within a substrate of sandy loam + red sand + cured cow manure (2:1:1). After sowing, the bags were kept for 3, 6 or 9 months at a place with direct sunlight. The variables of growth of the plants were not influenced either by the size of the recipients or by the periods of exposure. Although the size of the bags did not influence the development of the plants, the 20 x 30 cm size should be more practical and economical to be used. The 9 months growth period gave more vigorous plants.

Phytohormones strongly influence growth, development and nutritional quality of agricultural products by modulating molecular and biochemical changes. The purpose of the present study was to investigate the influence of root restriction (RR) treatment on the dynamic changes of main phytohormones during the berry development and ripening of “Summer Black” early ripening seedless grape (Vitis vinifera × V. labrusca), and to analyze the changes in the biosynthesis and signal transduction pathways of phytohormones by transcriptomics. Enzyme-linked immunosorbent assay (ELISA) and Ultra Performance Liquid Chromatography-High Resolution Mass Spectrometry (UPLC-HRMS) were used to quantify the phytohormone levels, and RNA-Seq was used to analyze the transcript abundance. The results showed that 23 transcripts involved in the phytohormone biosynthesis and 34 transcripts involved in the signal transduction pathways were significantly changed by RR treatment. RR also increased abscisic acid, brassinosteroid, ethylene, jasmonic acid and salicylic acid levels, while decreasing auxin, cytokinin, and gibberellin contents. The results of the present study suggest that RR treatment can accelerate the grape ripening process, and specific candidate genes were identified for further functional analysis.

In the southern of China, precipitation is abundant during the grape growing season, which results in lower sugar content, and finally reduces the quality and yield of grape berries and leads to lower economic benefits. The root restriction cultivation method is an important abiotic stress that limits the disordered growth and development of roots, and it favors the accumulation of sugar and abscisic acid. However, the relationship between ABA and sugar accumulation under root restriction remains unclear. Here, we tested the expression levels of several transcription factors and sugar metabolism-related genes and found that root restriction cultivation could induce higher expression of VvMYB15 and VvSWEET15. The VvMYB15 transcription factor was found to bind to the promoter of VvSWEET15 and activate its expression, furthermore, transient overexpression of VvMYB15 in strawberry fruits and grape berries can promote sugar accumulation and increase the expression level of sugar metabolism-related genes, indicating that VvMYB15 is a positive regulator of sugar accumulation. In addition, the endogenous ABA content and expression level of VvGRIP55 , which is highly responsive to ABA, were significantly increased under root restriction, and VvGRIP55 could bind to the promoter of VvMYB15 and activate its expression. Therefore, our results demonstrated that the ABA-responsive factor VvGRIP55 can promote sugar accumulation through VvMYB15 and VvSWEET15 , suggesting a mechanism by which ABA regulates sugar accumulation under root restriction. • Molecular cascade networks of sugar accumulation may be the interaction of ABA-VvGRIP55-VvMYB15- VvSWEET15 in grape berries under root restriction. • Flesh tissue samples from grape berry grown in vitro were used. • Root restriction cultivation is beneficial to sugar accumulation. [ABSTRACT FROM AUTHOR]

The root system is essential for the stable growth of plants. Roots help anchor plants in the soil and play a crucial role in water uptake, mineral nutrient absorption and endogenous phytohormone formation. Root-restriction (RR) cultivation, a powerful technique, confines plant roots to a specific soil space. In the present study, roots of one-year-old "Muscat Hamburg" grapevine under RR and control (nR) treatments harvested at 70 and 125 days after planting were used for transcriptome sequencing, and in total, 2031 (nR7 vs. nR12), 1445 (RR7 vs. RR12), 1532 (nR7 vs. RR7), and 2799 (nR12 vs. RR12) differentially expressed genes (DEGs) were identified. Gene Ontology (GO) enrichment analysis demonstrated that there were several genes involved in the response to different phytohormones, including abscisic acid (ABA), auxin (IAA), ethylene (ETH), gibberellins (GAs), and cytokinins (CTKs). Among them, multiple genes, such as PIN2 and ERF113, are involved in regulating vital plant movements by various phytohormone pathways. Moreover, following RR cultivation, DEGs were enriched in the biological processes of plant-type secondary cell wall biosynthesis, the defense response, programmed cell death involved in cell development, and the oxalate metabolic process. Furthermore, through a combined analysis of the transcriptome and previously published microRNA (miRNA) sequencing results, we found that multiple differentially expressed miRNAs (DEMs) and DEG combinations in different comparison groups exhibited opposite trends, indicating that the expression levels of miRNAs and their target genes were negatively correlated. Furthermore, RR treatment indeed significantly increased the ABA content at 125 days after planting and significantly decreased the IAA content at 70 days after planting. Under RR cultivation, most ABA biosynthesis-related genes were upregulated, while most IAA biosynthesis-related genes were downregulated. These findings lay a solid foundation for further establishing the network through which miRNAs regulate grapevine root development through target genes and for further exploring the molecular mechanism through which endogenous ABA and IAA regulate root architecture development in grapevine., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Li, Li, Li, Zahid, Li, Ma, Xu, Song, Li and Wang.)

[Display omitted] • Root restriction increased free terpenes concentrations by compounds conversion. • Root restriction had maximum impact on aroma compounds in the late stages. • Root restriction regulated aromatic series values and advanced aroma maturity date. • Terpenes played a central hub-like role in the networks of aroma compounds. • Ten bound compounds in pulp could indicate the developmental timing of grape. To systematically study the impact of root restriction (RR) on the aroma quality of grape berry, in this study, free and bound compounds were investigated in 'Red Alexandria' grape skin and pulp produced with and without RR during development and ripening. Compared with the control, RR advanced the initiation of free-terpene synthesis and increased their concentrations at 14–18 weeks post-flowering (wpf) by promoting the conversion of bound terpenes to free terpenes. In addition, RR significantly regulated the aromatic series at 14–18 wpf and advanced the date of aroma maturation. Network analyses indicated that the correlations among bound compounds were more conserved than those among free compounds, and the skin network displayed tight coordination compared with the pulp network. Terpenes were highly intercorrelated and played a core role in these networks. Finally, 10 bound compounds in pulp were screened out as indicators of the developmental timing of grape. [ABSTRACT FROM AUTHOR]

Root restriction (RR) has been reported to enhance grape berry quality in diverse aspects of grape life. In this study, RR-induced increases in the main primary metabolites in the grape berry and the expression of their related genes were studied at different developmental stages. Mainly the transcriptomic and metabolomic level were analyzed using 'Summer Black' grape berry as a material. The main results were as follows: A total of 11 transcripts involved in the primary metabolic pathways were significantly changed by the RR treatment. Metabolites such as sugars, organic acids, amino acids, starch, pectin, and cellulose were qualitatively and quantitatively analyzed along with their metabolic pathways. Sucrose synthase (VIT_07s0005g00750, VIT_11s0016g00470) and sucrose phosphate synthase (VIT_18s0089g00410) were inferred to play critical roles in the accumulation of starch, sucrose, glucose, and fructose, which was induced by the RR treatment. RR treatment also promoted the malic acid and tartaric acid accumulation in the young berry. In addition, the grape berries after the RR treatment tended to have lower pectin and cellulose content. [ABSTRACT FROM AUTHOR]

Root restriction was applied to 'Summer black' grape ( Vitis vinifera L. × Vitis labrusca L.) to investigate its effect on anthocyanin biosynthesis in grape berry during development. Anthocyanin composition and expression patterns of 16 genes in anthocyanin pathway were thus analyzed. The results showed that the anthocyanin levels in berry skin were significantly increased and the anthocyanin profile was enriched. Gene expression pattern revealed that the increased anthocyanins coincide with the up-regulated expression of all 16 genes investigated, including phenylalanine ammonia-lyase, 4-coumarate CoA ligase, chalcone synthase 1, chalcone synthase 2, chalcone synthase 3, chalcone isomerase, flavanone 3-hydroxylase 1, flavanone 3-hydroxylase 2, flavonoid 3′-hydroxylase ( F3′H), flavonoid 3′,5′-hydroxylase ( F3′5′H), di-hydroflavonol 4-reductase, leucoanthocyanidin dioxygenase, O-methyltransferases ( OMT), UDP-glucose:flavonoid 3- O-glucosyl-transferase ( 3GT), UDP-glucose:flavonoid 5- O-glucosyl-transferase ( 5GT) and glutathione S-transferase ( GST). The increased total anthocyanins predominantly resulted from the increase of tri-hydroxylated, methoxylated and mono-glycosylated rather than di-hydroxylated, non-methoxylated, and di-glycosylated forms, which might be due to the differential regulation of F3′5′H/F3′H, OMT and 3GT, respectively. [ABSTRACT FROM AUTHOR]

Abstract: To unravel the inhibition of root restriction on shoot growth, the changes of nitrogen levels and glutamine synthetase (GS, EC 6.3.1.2) activity were investigated in four-year-old root-restricted ‘Kyoho’ grapevines (Vitis vinifera × Vitis labrusca) in greenhouse from veraison up until 62 days after harvest. ‘Kyoho’ grapevines were planted in buried bed as root restriction and in raised bed (unrestricted rooting zone) as the control. Results showed that root restriction significantly decreased the total amount of N in leaves, berry flesh, white and brown roots, (NO3 − +NO2 −)–N content in leaves, white and brown roots, and NH4 +–N content in brown roots. In addition, root restriction reduced not only N remobilization and recycling from leaves to roots after harvest, but also the total GS activity in both leaves and roots, suggesting that root restriction has a negative influence on glutamine synthesis in grapevines. However, soluble protein content in both leaves and white roots significantly increased under root restriction from 118 to 180 days after anthesis (DAA). It can be attributed to the increased synthesis of polypeptides and/or the enhanced de novo synthesis of proteins in root-restricted vines. In summary, the results illustrated less N reserve in root-restricted vines, which might be responsible for shoot growth inhibition under root restriction. [Copyright &y& Elsevier]

Abstract: Root restriction improved berry quality in grapevine, including better coloration and increased anthocyanin accumulation at harvest. However, detailed biochemical data was unavailable for the development of individual anthocyanins during berry ripening to elucidate the increased anthocyanins accumulation under root restriction. In this study, compositional changes in skin anthocyanins were investigated in ‘Kyoho’ grape (Vitis vinifera L.× Vitis labrusca L.) under root restriction from veraison to ripening by HPLC–ESI-MS. Four-year-old ‘Kyoho’ grapevines were planted in wooden boxes as root restriction and the conventional ground planting as the control. Results showed that root restriction significantly increased the total and individual anthocyanins levels in berry skin. 25 anthocyanins were identified in berry skin of ‘Kyoho’ grape under root restriction, with five of them undetectable in the control. Furthermore, root restriction resulted in a higher percentage of delphinidin and cyanidin derivatives and a lower percentage of peonidin derivatives during berry ripening. More modified anthocyanidins, such as coumaroylated and diglycosylated derivatives were detected under root restriction. [Copyright &y& Elsevier]

Rooting space is considered as a resource in plants, but comparative studies on the biomass allocation plasticity in response to rooting volume (RV) are rare. We compared responses in growth, biomass allocation and ontogenetic heteroblasty in nine hard pine species of contrasted ecology. Seedlings were cultivated in containers of 0.2, 0.5, 1.0, 2.8 and 7 L for two growing seasons (425 days). Reduction in RV caused a reduction in plant absolute and relative growth rate and biomass allocated to stems but it increased biomass allocated to roots. RV affected to a lesser extent and in a less consistent direction allocation to leaves. Species that grew faster (higher relative growth rate) had a steeper decrease in growth with the reduction in RV. Ontogenetic heteroblasty, evaluated as the proportion of secondary needles in the needle biomass, showed highly different plasticity patterns in response to RV. Decrease in RV caused negligible or no change either in the most ontogenetically delayed Mediterranean pines or in the most ontogenetically advanced pines, the mesic Pinus sylvestris and P. uncinata. By contrast, ontogenetically intermediate species showed steep reaction norms in response to reduction in RV. While P. pinaster and P. brutia showed marked rejuvenation, P. nigra accelerated the development of adult foliage. [ABSTRACT FROM AUTHOR]

Even though advances have been made in the techniques of seedling production, there are still many problems to be solved, especially with regard to the development of the root system of seedlings, depending on the containers used. The objective of this study was to determine the effect of recipient size and the plant cultivation time in the production of C. hospita seedlings. Seeds of carnauba (Copernicia hospita Martius) obtained from mature fruit, were pre-germinated and sown in plastic 20 x 30, 28 x 40 and 40 x 60 cm bags, within a substrate of sandy loam + red sand + cured cow manure (2:1:1). After sowing, the bags were kept for 3, 6 or 9 months at a place with direct sunlight. The variables of growth of the plants were not influenced either by the size of the recipients or by the periods of exposure. Although the size of the bags did not influence the development of the plants, the 20 x 30 cm size should be more practical and economical to be used. The 9 months growth period gave more vigorous plants. [ABSTRACT FROM AUTHOR]

Tap-rooted rapeseed is generally considered sensitive to soil compaction. We examined 473 Finnish rapeseed fields sown in 2007 to 2009 to both spring turnip rape Brassica rapa L. (dominant crop) and oilseed rape Brassica napus L. Roots were rated late in the growing season according to penetration capacity. Roots in each field were rated from G1 (no problems with root penetration) to G5 (failure to penetrate deeper soil layers). There were significant effects of year, crop species, soil type, special soil properties and soil cultivation methods on frequency of G1 and G4+5 roots. Restricted root penetration was a common phenomenon. Typically, fields had <30% G3 and G4+5 roots, however, some fields had >70% G4+5 roots and were cases for serious concern. Yield loss was linearly related to the incidence of G4+5 plants in 2007, but there was no relationship with the other years. Oilseed rape had a greater proportion of G4+5 roots than turnip rape and twice the proportion of G4+5 roots occurred in direct-drilled fields than in reduced or fully tilled fields. Rapeseed yield decline may at least partly be related to poor root penetration and it is a useful indicator crop to demonstrate the degree of soil compaction and should be cultivated in fields where sufficient root penetration is possible. [ABSTRACT FROM AUTHOR]

The article discusses research on plug cell size and how they can affect the growth and yield and in the propagation of the domestic cut rose or Rose hybrida. Researchers Yoo Gyeong Park et al. prepared scions as single node cuttings then grafted them on rootstock Rose indica Major cuttings and data on the treatment plot were analyzed for statistical significance using the Statistical Analysis System (SAS) software. Findings indicated the increased stem length and leaf number with the bigger plug cell size.

The article examines the important concepts of urban trees' root system architecture. According to the authors, knowledge of the extent and distribution of tree root systems is important for the management of trees in a built environment. The article examines the literature on tree root growth in urban settings as well as literature on root architecture in nonurban settings that are important in understanding tree roots in built settings.

In this study, the ultrastructure of phloem and its surrounding parenchyma cells in the developing grape berry produced under root restriction or without (control) was for the first time systematically investigated through transmission electron microscopy during the entire developmental process of the berry. The results showed that root restriction increased the number of plasmodesmata between sieve elements (SE) and companion cells (CC) and between the SE/CC complex and phloem parenchyma cells. Sieve elements in fruit produced under root restriction were smaller in size than those from the control treatment, but CC were bigger than in the control treatment. During the first rapid growth phase of the grape berry, there was denser cytoplasm in the CC produced under root restriction having more abundant mitochondria, endoplasmic reticulum, multivesicular bodies, vesicles, and plastids than in control fruit. During the second rapid growth phase of the grape berry, CC under root restriction showed more serious plasmolysis. Cytoplasmic contents such as vesicles were fused into the vacuole of which the tonoplast nearly disappeared in the phloem parenchyma cells, and cytoplasmic contents in fruit cells produced under root restriction became denser than the control treatment. These results demonstrated that grape berry adapted to the root restriction stress through ultrastructure variation of the phloem, and this variation explained the increase of photosynthate accumulation in the grape berry observed under root restriction. [ABSTRACT FROM AUTHOR]

Abstract: Root restriction often depresses photosynthetic capacity and the mechanism for this reduction, however, remains unclear. To identify the mechanism by which root restriction affects the photosynthetic characteristics, tomato (Lycopersicon esculentum Mill.) seedlings were subjected to root restriction stress with or without supplemental aeration to the nutrient solution. With the development of the root restriction stress, CO2 assimilation rate was decreased only in confined plants without supplemental aeration. There were also significant decreases in leaf water potential, stomatal conductance (g s), intercellular CO2 concentration (C i), and increases in the stomatal limitation (l) and the xylem sap ABA concentration. Meanwhile, the maximum carboxylation rate of Rubisco (V cmax) and the capacity for ribulose-1,5-bisphosphate regeneration (J max) also decreased, followed by substantial reductions in the quantum yield of PSII electron transport (Φ PSII). Additionally, root restriction resulted in accumulation of carbohydrates in various plant tissues irrespective of aeration conditions. It is likely that root restriction-induced depression of photosynthesis was mimicked by water stress. [Copyright &y& Elsevier]

Abstract: Arbuscular mycorrhizal (AM) fungi colonize most plant species in the savannah/oak woodland ecosystem of the California Sierra Foothills. These fungi may form belowground linkages between plant root systems, potentially altering nutrient transfers. In a laboratory experiment with two-chambered pots where only AM fungal hyphae connected the chambers, we examined nutrient transfer between native plant species of grasses and forbs. Two separate chambers with plants were separated by a set of two stainless steel screens (25μm mesh) separated by a 1cm air gap. These screens successfully restricted root growth but allowed hyphal coverage (15–100% of the area) of the screens. Nutrient transfers were monitored by applying nitrogen (15N), arsenic (P analog), strontium (Ca analog), and cesium and rubidium (K analogs). The analogs and 15N were applied to leaves of donor plants for 48h. We observed transfer of 15N, As, Cs, and Rb from donor shoots to receiver shoots. Element transfers were not correlated with receiver biomass or donor concentrations. Transfers varied among the elements and plant combinations. Both Rb and Cs (K analogs) had the same pattern of transfer. Nitrogen was transferred in greatest amounts and between forbs and grasses, and grasses acted as a stronger sink for N. Forbs were generally the stronger sink for As. Fungal hyphae facilitated transfer among forbs and grasses, suggesting that they have a key role in nutrient transfer in California oak woodlands. [Copyright &y& Elsevier]

To investigate whether O2 deficit is involved in the depressed shoot growth under root restriction condition, tomato (Lycopersicon esculentum Mill.) plants were grown hydroponically and subjected to root restriction with or without supplemental aeration. Plant biomass, leaf nutrient concentration, dissolved O2 concentration in nutrient solution, root respiration, root hydrolytic ATPase activities, xylem sap abscisic acid (ABA) concentration, water relations, leaf gas exchange, and root cell viability were investigated throughout the experiment. Root restriction significantly depressed root and shoot growth as early as 15 days after treatment and this depressive effect was alleviated by vigorous aeration around the restricted root zone. Growth suppression by root restriction occurred concomitantly with sharp decreases in dissolved O2 concentration in solution together with significant decreases in root total respiration, cytochrome pathway capacity, hydrolytic ATPase activities, and root cell viability. However, no such decreases were found in well aerated root restriction plants. Root restriction-induced growth suppression was independent of nutrients level in leaves and was not primarily related to the decline of leaf water potential or the gas exchange. Root restriction resulted in an increase in xylem sap ABA concentration from day 15 to the end of the experiment but no such effect was observed in well aerated plants. It is likely therefore, that O2 was one of the main limiting factors to the reduced shoot growth under root restriction condition. [Copyright &y& Elsevier]

The article studies the process of using organic changes to decrease bulk density and to increase macroporosity in compacted soils. Several samples of compacted sandy loam and clay loam were changed with organic matter like sphagnum peat or food waste compost. Changes were made into the soil samples on a volume-to-volume basis.

Abstract: To examine the effect of root restriction on the nitrate uptake and the nitrate transport system activity, 2-year old “Fenghou” grapevines (Vitis Vinifera × V. Labrasca) were planted in pots with volume 2L and 12L served as root restriction and the control, respectively. The pots were filled with perlite and watered with rainwater and nutrient solution. Vine growth and kinetics of nitrate uptake in vine roots were evaluated. The results showed that root restriction significantly inhibited the shoots and roots growth, enhanced the nitrate uptake rate, decreased the kinetics parameter K m value and increased V max value, that is to say, root restriction depressed the affinity of nitrate high-affinity transport system (HATS) and improved the nitrate uptake rates of both high (HATS) and low-affinity transport system (LATS). However, root restriction significantly decreased the amount of net nitrate uptake, which led to the low nitrate concentration in leaves and roots. [Copyright &y& Elsevier]

Two studies were conducted to determine container size and liner (young bare root trees) trunk diameter effects on growth of Acer rubrum L. 'Franksred', Red Sunset™ red maple. In experiment 1, maples liners with initial mean trunk diameters of 12.2 mm (0.5 in), 15.9 mm (0.6 in), and 22.3 mm (0.9 in) were potted in 26.5 liter (#7), 37.8 liter (#10), and 56.8 liter (#15) containers and grown for 18 months (2 growing seasons). Height and trunk diameter growth at the end of each growing season were affected by both the initial liner trunk diameter and container size. During year 1, liners with an initial trunk diameter of 12.2 mm (0.5 in) increased 28 and 70% more in height growth compared to liners initially 15.9 mm (0.6 in) and 22.3 mm (0.9) in trunk diameter, respectively. Twenty three percent more height growth occurred with maples in 37.8 liter (#10) and 56.8 liter (#15) containers compared to those in 26.5 liter (#7) containers. Trunk diameter growth increased 50% more with 12.2 mm (0.5 in) liners compared to 22.3 mm (0.9 in) liners. A 25% increase in trunk diameter growth occurred with liners potted in 56.8 liter (#15) compared to 26.5 liter (#7) containers. At the end of the second growing season, final tree size was similar with liners that were initially 12.2 mm (0.5 in) and 15.9 mm (0.6 in) liners in trunk diameter to those initially 22.3 mm (0.9 in) when potted into 37.8 liter (#10) and 56.8 liter (#15) containers. In experiment 2, maple liners with trunk diameters 17.5 mm (0.7 in), 20.5 mm (0.8 in), and 29.0 mm (1.1 in) were potted in container sizes 26.5 liter (#7), 37.8 liter (#10), and 56.8 liter (#15) and grown for 18 months (2 growing seasons). Liners grown in 56.8 liter (#15) containers had 92% more height growth and 48% more trunk diameter growth than with liners in 26.5 liter (#7) containers, At termination, the shoot dry weight was 41% larger with maples in 56.8 liter (#15) containers compared to those grown in 26.5 liter (#7) containers. [ABSTRACT FROM AUTHOR]