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• 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]

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]

[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]

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]

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]

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]

Abstract: Two-year-old ‘Fujiminori’ grapevines (Vitis Venifera × V. Labrasca) planted in plastic pots (10L) were used to evaluate vine growth and nitrogen metabolism in response to root restriction. Results show that root restriction reduced shoot growth and photosynthetic rate, but promoted root growth in vines. NO3 −-N concentration in all plant parts, and total N concentrations in brown roots and new leaves were decreased by root restriction, and chlorophyll and carotenoid concentrations in mature leaves were also reduced. Nitrate and nitrite reductase activities in brown roots and mature leaves were significantly reduced in root-restricted vines. The results suggest that the reduction of nitrate and nitrite reductase activities caused the inhibition of nitrogen assimilation, and this might be an important reason for root restriction inhibiting shoot growth. [Copyright &y& Elsevier]

Abstract: The interactive effects of rooting volume and nutrient availability in a skeletal soil medium designed to meet street tree and pavement needs were observed in a containerized experiment. Benjamin fig (Ficus benjamina L.) was grown in a stone-soil blended skeletal soil material (CU-Soil™) and compared to a loam soil. The same topsoil used as the soil component in the skeletal soil material was used as the sole component in the comparison soil-only treatment. Plants grown in the skeletal soil material had reduced leaf tissue N content and depressed growth compared with plants grown in non-diluted soil. No other mineral deficiencies were found. Leaf number, chlorophyll concentration, shoot weight, and root characteristics were all affected. Reduced growth from soil dilution could be offset by the provision of an enlarged rooting volume for root development. Large containers of skeletal soil were observed to have smaller root systems compared to equivalent net volumes of loam soil at the first two harvest dates of the study. By the end of the study, the large containers of skeletal soil were observed to have developed larger root systems compared to equivalent net volumes of loam soil; resulting in comparable leaf N levels and total plant dry matter. Plants in skeletal soil had lower shoot: root ratios at the end of the study. Investing resources to further root growth in times of nutrient shortages is a probable plant reaction as evidenced by differences in specific root length between treatments. The study allowed a method for directly partitioning the containerization effect by having equivalent amounts of soil over two volumes. [ABSTRACT FROM AUTHOR]

• Root restriction, as a new cultivation way, was widely applied in crop production. • The genes associated with ABA biosynthesis, catabolism and signal transduction was identified by Transcriptome. • PP2C, NCED, AAO3, ABA3 and CYP707A1 may play an important role in root restriction induced fruit quality promotion. Root restriction is a critical cultivation technique that accelerates ripening and improves fruit quality, by a still unknown mechanism. ABA is an important phytohormone in both ripening and stress responses. To elucidate the relationship between ABA content and root restriction-induced fruit quality promotion, the endogenous ABA level was investigated in five-year-old 'Muscat Hamburg' grapevines from the pre-anthesis stage to maturity. The results showed that ABA production was significantly enhanced by root restriction. A transcriptomics-based approach was taken to identify transcriptionally regulated genes associated with ABA biosynthesis, catabolism and signal transduction in the four development periods of grape. A total of 2873 (884 upregulated and 1989 downregulated) DEGs were identified in all stages. Those related to metabolic processes, cellular processes, responses to stimuli, biological regulation and signal transduction were abundant in the biological process GO category. KEGG analysis revealed that plant hormone signal transduction and carotenoid biosynthesis were enriched out of the 127 total pathways. 12 DEGs involved in ABA biosynthesis and catabolism and 69 DEGs involved in plant hormone signal transduction were significantly regulated by root restriction. Twelve DEGs related to the biosynthesis and catabolism of ABA or plant hormone signal transduction were selected to validate the data obtained by RNA-Seq, and the results showed that genes such as PP2C, NCED, AAO3, ABA3, and CYP707A1, involved in ABA biosynthesis and signal transduction, may play important roles in the promotion of fruit quality by root restriction. This study suggests a potential ABA-mediated mechanism by which root-restriction cultivation promotes fruit ripening. [ABSTRACT FROM AUTHOR]