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Abstract Greenhouses are complex systems that require considerable amounts of energy. In order to optimize their performance, it is necessary to reduce the amount of energy per unit of crop produced. This requires a combined assessment of greenhouse energy balance and crop growth, as well as their interaction. In this work, more than 30 existing greenhouse models are reviewed and different algorithms are combined to propose an integrated energy-yield model. The physical model of greenhouse energy demand is based on the dynamic energy and mass balance while yield production is based on a physiological crop model. The integrated model is validated with observed energy demand and crop yield datasets during one full tomato growing period. There was good agreement between modeled results and measured data. The key advantage of the integrated model is that it can analyze drivers for greenhouse energy losses and quantify the influence of measures on both energy demand and crop yield. Due to the model's dynamic and high temporal resolution, it is possible to study the use of renewable energy sources in greenhouse operation, as illustrated for thermal storage by means of phase change materials. A sensitivity analysis by changing day/night temperature, CO 2 indoor concentration and artificial lighting is performed. The results illustrate how the model can be used for optimizing the performance of greenhouses in terms of specific energy demand (energy per crop produced). Therefore, the integrated model can be a tool for determining the optimum design and control parameters, which is particularly relevant for growers and sustainable agriculture systems in general. This study presents a parametric decision support tool that assists planers with optimizing energy performance of greenhouses while analyzing the trade-off between energy demand and crop yield. Graphical abstract fx1 Highlights • Greenhouse energy demand and crop yield models are integrated. • A newly integrated dynamic model of greenhouse showed good agreement with reality. • The novel framework improves state-of-the-art of greenhouse energy-crop yield models. • Drivers of the greenhouse energy losses are analyzed and quantified. • Sensitivity analysis confirms the ability of the integrated model to be used as a decision support tool. [ABSTRACT FROM AUTHOR]

Potato ( Solanum tuberosum L.) is an important crop in the Gamo Highlands in Ethiopia. The region is characterised by a complex topography with large inter-annual weather variations, where potatoes grow in a range of altitudes between 1,600 and 3,200 m above sea level (a.s.l.). Traditional large-scale crop modelling studies only crudely represent the effect of complex topography, misrepresenting spatial variability in meteorology and potato growth in the region. Here, we investigate how weather influenced by topography affects crop growth. We used the Weather Research and Forecasting (WRF) model to simulate weather in relation to topography in coarse (54 km × 54 km) and fine (2 km × 2 km) resolution domains. The first has a resolution similar to those used by large-scale crop modelling studies that only crudely resolve the horizontal and vertical spatial effects of topography. The second realistically represents the most important topographical variations. The weather variables modelled in both the coarse and fine resolution domains are given as input to the GECROS model (Genotype-by-Environment interaction on CROp growth Simulator) to simulate the potato growth. We modelled potato growth from 2001 to 2010 and studied its inter-annual variability. This enabled us to determine for the first time in Ethiopia how variations in weather are linked to crop dynamics as a function of elevation at a fine resolution. We found that due to its finer representation of topography, weather and crop growth spatio-temporal variations were better represented in the fine than in the coarse resolution domain. The magnitude of crop growth variables such as Leaf Area Index (LAI) and Length of the Growing Season (LGS) obtained with weather from the coarse resolution domain were unrealistically low, hence unacceptable. Nevertheless, the resulting potato yields in the coarse resolution domain were comparable with the yields from the fine resolution domain. We explain this paradoxical finding in terms of a compensating effect , as the opposite effects of temperature and precipitation on yield compensated for each other along the major potato growing transect in the Gamo Highlands. These offsetting effects were also dependent on the correct estimations of the LGS, LAI. We conclude that a well-resolved representation of complex topography is crucial to realistically model meteorology and crop physiology in tropical mountainous areas. [ABSTRACT FROM AUTHOR]

Highlights • We tested whether rice plants can recognize and record natural variation in their growth environments and thus control flowering in their progeny. • We found that the progeny of mother plants of both cultivars grown in a cool climate flowered significantly earlier than the progeny of mother plants grown in a warm climate. • This transgenerational effect was partially explained by water temperatures during the vegetative growth stage. Abstract Flowering date reflects the adjustment of a plant’s growth period to a given environment. This is true of rice, which is a major food source around the world. We tested whether rice plants can recognize and record natural variation in their growth environments and thus control flowering in their progeny. We grew seedlings of two japonica cultivars from the same seed stock at two locations, in cool and warm climates, in Japan until they produced seeds. We then tested their progeny at the same locations. The progeny of mother plants of both cultivars grown in a cool climate flowered significantly earlier (by 1 to 6 days) than the progeny of mother plants grown in a warm climate. This transgenerational effect was partially explained by water temperatures during the vegetative growth stage. This is the first study to show the effect of transgenerational effect of natural environments on flowering date in rice. [ABSTRACT FROM AUTHOR]

Highlights • JIHR had considerable yield superiority over JIR and IHR, attributed mainly to the larger sink through more spikelets per panicle. • JIHR had the better root mopho-physiological traits during grain filling compared with JIR and IHR. • The better root mopho-physiology of JIHR could contribute to the shoot stay-green traits, higher biomass accumulation, and its yield superiority. Abstract Grain yield superiority of japonica/indica hybrid rice (JIHR) over japonica inbred rice (JIR) and indica hybrid rice (IHR) was reported, and some shoot traits underlying high yield of JIHR were identified, like shoot stay-green traits after heading. To date, little information has focused on root trait differences among JIHR, JIR and IHR. Besides, improved shoot stay-green traits after heading of JIHR might indicate better root morpho-physiological traits after heading compared with JIR and IHR, considering the interdependent relationship between root and shoot. In this study, two JIHR, two JIR, and two IHR were planted in 2014 and 2015 at Ningbo, and in 2015 and 2016 at Yangzhou, China. JIHR showed longer total growth period especially the period from heading to maturity and higher grain yield per day, and 5.6–19.8% higher grain yield compared with JIR and IHR across two years at two sites. JIHR had consistently higher root and shoot biomass at heading and maturity at two sites compared with JIR and IHR. Higher root length and root volume, and more roots in the 11–30 cm soil depth at heading and maturity of JIHR over JIR and IHR were observed across years and sites. JIHR had not only higher leaf SPAD value and leaf photosynthetic rate, but also higher root bleeding rate and root oxidation activity during grain filling, compared with JIR and IHR. JIHR had lower reduction rate of root biomass, length, volume, bleeding rate, and oxidation activity from heading to maturity than JIR and IHR at two sites. Root length and root volume were correlated positively (P < 0.01) to shoot biomass at heading and maturity and rice grain yield. Root bleeding rate and root oxidation activity were correlated positively (P < 0.01) to leaf SPAD value and leaf photosynthetic rate during grain filling and rice grain yield. Our results suggested that better root morpho-physiological traits (showing as longer, larger, deeper, and more active roots) after heading of JIHR could contribute to the shoot stay-green traits, higher biomass accumulation, and finally yield superiority over JIR and IHR. [ABSTRACT FROM AUTHOR]

Upland cotton (Gossypium hirsutum L.) growth and development during the pre-and post-flowering stages are susceptible to high temperature and drought. We report the field-based characterization of multiple morpho-physiological and reproductive stress resilience traits in 11 interspecific chromosome substitution (CS) lines isogenic to each other and the inbred G. hirsutum line TM-1. Significant genetic variability was detected (p < 0.001) in multiple traits in CS lines carrying chromosomes and chromosome segments from CS-B (G. barbadense) and CS-T (G. tomentosum). Line CS-T15sh had a positive effect on photosynthesis (13%), stomatal conductance (33%), and transpiration (24%), and a canopy 6.8 °C cooler than TM-1. The average pollen germination was approximately 8% greater among the CS-B than CS-T lines. Based on the stress response index, three CS lines are identified as heat- and drought-tolerant (CS-T07, CS-B15sh, and CS-B18). The three lines demonstrated enhanced photosynthesis (14%), stomatal conductance (29%), transpiration (13%), and pollen germination (23.6%) compared to TM-1 under field conditions, i.e., traits that would expectedly enhance performance in stressful environments. The generated phenotypic data and stress-tolerance indices on novel CS lines, along with phenotypic methods, would help in developing new cultivars with improved resilience to the effects of global warming.

The effects of microplastics on crop plants have attracted growing attention. However, little is known about the effects of microplastics and their extracts on the growth and physiology of wheat seedlings. In this study, hyperspectral-enhanced dark field microscopy and scanning electron microscopy were used to accurately track the accumulation of 200 nm label-free polystyrene microplastics (PS) in wheat seedlings. The PS accumulated along the root xylem cell wall and in the xylem vessel member and then moved toward to the shoots. In addition, lower concentration (≤ 5 mg·L−1) of microplastics increased root hydraulic conductivity by 80.6 %− 117.0 %. While higher PS treatment (200 mg·L−1) considerably decreased plant pigments content (chlorophyll a, b, and total chlorophyll) by 14.8 %, 19.9 %, and 17.2 %, respectively, and decreased root hydraulic conductivity by 50.7 %. Similarly, catalase activity was reduced by 17.7 % in root and 36.8 % in shoot. However, extracts from the PS solution showed no physiological effect on wheat. The result confirmed that it was the plastic particle, rather than the chemical reagents added in the microplastics, contributed to the physiological variation. These data will benefit to better understanding on the behavior of microplastics in soil plants, and to providing of convincing evidence for the effects of terrestrial microplastics. [Display omitted] • Hyperspectral images can accurately detect the localization of microplastics in plant tissues. • Microplastics accumulated along the wheat root xylem cell wall and in the xylem vessel member. • Higher concentration of microplastics can induced photosynthetic impairment and oxidative damage in wheat seedlings. • The microplastic extracts had no significant effects on the growth and physiology of wheat seedlings. [ABSTRACT FROM AUTHOR]

The enhancement of the actual low yields is the most important challenge regarding organic farming management. In this view, a valid tool may arise by the improvement of fertilization management and efficiency. In this regard, arbuscular mycorrhizal fungi (AMF) can play an important role, especially in low fertility soils such as calcareous ones, through a better nutrient uptake and by alleviating abiotic stresses. A replicated-space experiment was carried out to investigate the role of mycorrhizal-based inoculants combined with full or halved fertilizer doses on yield and physiological traits of three early potato cultivars organically grown in highly calcareous and alkaline soils. The results indicate that AMF symbiosis ameliorated, in comparison to the not-inoculated plants, the potato tolerance to limestone stress by enhancing the potential quantum efficiency of photosystem II (Fv/F0) and plant gas-exchange parameters (photosynthesis rate and stomatal conductance). Moreover, a significant improvement of marketable yield (+25%) was observed, mainly due to an increase of the number of tubers plant−1 (+21%) and, to a lesser extent, of average tuber weight (+10%). The AMF efficiency was higher applying halved fertilizer doses and in the location where soil conditions were unfavourable for potato growth. Moreover, the qRT-PCR highlighted that AMF colonization was similar in each location, demonstrating their tolerance to limestone, alkalinity and P stresses. These findings outlined that AMF are good candidate to bio-ameliorate calcareous soils and are very useful for improving potato yields under organic farming, limiting external fertilizers supply and environmental pollution.

The article presents the results of research consisting of the application of deficit irrigation (DI) criteria, combined with the adoption of micro-irrigation methods, on orange orchards (Citrus sinensis (L.) Osbeck) in Sicily (Italy) during the irrigation season of 2015. Regulated deficit irrigation (RDI, T3) and partial root-zone drying (PRD, T4) strategies were compared with full irrigation (T1) and sustained deficit irrigation (SDI, T2) treatments in terms of physiological, biochemical, and productive crop response. A geophysical survey (electrical resistivity tomography, ERT) was carried out to identify a link between the percentages of drying soil volume in T4 with leaves abscisic acid (ABA) signal. Results highlight that the orange trees physiological response to water stress conditions did not show particular differences among the different irrigation treatments, not inducing detrimental effects on crop production features. ABA levels in leaves were rather constant in all the treatments, except in T4 during late irrigation season. ERT technique identified that prolonged drying cycles during alternate PRD exposed more roots to severe soil drying, thus increasing leaf ABA accumulation.

We present a high throughput crop physiology condition monitoring system and corresponding monitoring method. The monitoring system can perform large-area chlorophyll fluorescence imaging and multispectral imaging. The monitoring method can determine the crop current condition continuously and non-destructively. We choose chlorophyll fluorescence parameters and relative reflectance of multispectral as the indicators of crop physiological status. Using tomato as experiment subject, the typical crop physiological stress, such as drought, nutrition deficiency and plant disease can be distinguished by the monitoring method. Furthermore, we have studied the correlation between the physiological indicators and the degree of stress. Besides realizing the continuous monitoring of crop physiology, the monitoring system and method provide the possibility of machine automatic diagnosis of the plant physiology.Highlights: A newly designed high throughput crop physiology monitoring system and the corresponding monitoring method are described in this study. Different types of stress can induce distinct fluorescence and spectral characteristics, which can be used to evaluate the physiological status of plants.

Abstract: Salt stress is a major yield‐limiting factor in crops by reducing nutrient uptake and plant growth. Under salt stress, decreased water and nutrient uptake results in nutrient imbalance in plants. In addition, at high pH in saline conditions, solubility of minerals is also reduced leading to low availability of certain nutrients. Perspectives to overcome these limitations by Zn seed priming were studied with maize plants exposed to NaCl as salt stress. Maize seeds were primed for 24 hr in deionized water and 4 m m ZnSO4·7H2O solution (ZnP) and subsequently air‐dried at room temperature before further use. The DTZ (diphenylthiocarbazone) staining method was used for showing Zn2+ localization in the seeds. Zn2+ and other nutrient concentrations in unprimed, water and ZnP seeds and maize plants were analysed by inductively coupled plasma mass spectroscopy (ICP‐MS). Maize plants (cv. Sun star L.) were grown for 3 weeks in complete nutrient solution with or without salt stress (100 m m NaCl) under glasshouse conditions. Seed Zn2+ contents were increased after ZnP treatment by 600%. In maize seeds, most of the primed Zn2+ accumulated in the outer tissues (particularly, aleurone layer) of maize seed. Zn priming decreased the injurious effects of salt stress on plant growth. Under salt stress conditions, biomass production of plants from ZnP treatments was 25% higher compared to water priming treatment. Zn seed priming also improved mineral nutrient status of plants grown in both control and salt stress conditions. Plants from ZnP treatments also showed higher accumulation of Na+ in the shoots. This offers perspectives for using Zn seed priming for improving early seedling development and plant nutrient status of maize under salt stress conditions. [ABSTRACT FROM AUTHOR]

Air temperature is one of the most critical climatic factors controlling rice growth, development, and production in current and future climatic scenarii predicting increasingly frequent situations of extreme and/or fluctuating temperatures. With its large spectrum of geographical origins and cropping areas, one can credit tropical japonica rice subspecies of a probable genetic diversity of its response to air temperature, which is of major interest for the breeding of better adapted rice varieties. A panel of 195 rice accessions (175 japonica plus 20 reference cultivars) was studied in controlled environment to estimate cardinal (base, optimum, and maximum) temperatures based on the monitoring of the elongation rate (LERmax) of the sixth leaf on the main stem in response to six fixed thermal treatments ranging from 16 to 35 °C. A dedicated statistical framework was elaborated for estimating LERmax, cardinal temperature and related uncertainties. Developed statistical framework enhanced the precision of cardinal temperatures estimated compared to previously reported methods, especially for base temperature. Maximum temperature was trickier to estimate and will require further studies. A significant genotypic variability for base and optimal temperature was pointed out, suggesting tropical japonica subspecies represents a relevant genetic pool to breed for rice genotypes adapted to various thermal situations. These results also suggested that using genotype-dependent cardinal temperature values should enhance the way crop growth models account for genotype × environment interactions hence their predictive value in current and future climatic conditions. [ABSTRACT FROM AUTHOR]

Tachisuzuka, a rice cultivar for whole-crop silage, is characterized by a small panicle and high sugar content in the stem. Our previous study suggests that the high sugar content in the stem of Tachisuzuka is due to a factor other than the small panicle. To characterize sugar metabolism in the stem of Tachisuzuka, here we compared carbohydrate content, enzyme activity, and the expression of genes involved in sugar metabolism in the stem between Tachisuzuka and its parental variety, Kusanohoshi. Thinning the panicles of Kusanohoshi increased the starch content in the leaf sheath and internode but did not increase the sucrose content in the leaf sheath to the same level as that of Tachisuzuka. This suggests that Tachisuzuka has high potential to accumulate sucrose in its leaf sheath. Comparison of enzyme activity showed that the hexokinase activities in the leaf sheath tended to be higher in Tachisuzuka than Kusanohoshi or panicle-thinned Kusanohoshi, suggesting that glucokinase or fructokinase affects sugar accumulation in the stem of Tachisuzuka. Comparative transcriptome analysis revealed the differences in expression levels of carbohydrate-related genes between Tachisuzuka and Kusanohoshi. In particular, the expression levels of ISA2, which encodes starch-debranching enzyme, and TMT2, which encodes tonoplast monosaccharide transporter - both of which maybe involved in sugar accumulation in grass stems - were higher in Tachisuzuka than Kusanohoshi. Thus, these enzymes and transporters may contribute to the high sugar content in the stem of Tachisuzuka. [ABSTRACT FROM AUTHOR]

Enhancing rice yield in upland rice systems through genetic improvement remains a major challenge in the tropics. This review aims to provide the trends on upland rice cultivation over the last 30 years and recent distribution of upland rice in the tropics, and to report progress in studies on genetic improvement for enhancing productivity in Africa, Asia, and Latin America. While upland rice cultivation area has reduced in Asia and Latin America over the last 30 years, the area in Africa has increased. The current share of upland rice area in total rice area is related to rainfall and gross national income per capita, especially in Africa, and higher share is associated with lower rice selfsufficiency at national level. Breeding programs in Asia and Latin America have developed highyielding varieties using indica materials as parents. In Africa, New Rice for Africa (NERICA) varieties were developed from crosses between improved tropical japonica and Oryza glaberrima. However, recent studies report that there is scope for improving existing NERICA using upland indica materials from Asia. In highlands of Africa, there are ongoing breeding programs using japonica varieties, such as the Nepalese Chhomrong Dhan. Key important plant traits used in the breeding programs are not largely different across regions, especially intermediate plant height and tillering capacity (which may be related to weed-suppressive ability), and high harvest index. In conclusion, we propose an international network for breeding upland rice with accelerating seed exchange across regions that could enhance upland rice productivity through genetic improvement. [ABSTRACT FROM AUTHOR]

Abstract: Responses of wheat (Triticum aestivum) to complete submergence are not well understood as research has focused on waterlogging (soil flooding). The aim of this study was to characterize the responses of 2 wheat cultivars differing vastly in submergence tolerance to test if submergence tolerance was linked to shoot carbohydrate consumption as seen in rice. Eighteen‐day‐old wheat cultivars Frument (intolerant) and Jackson (tolerant) grown in soil were completely submerged for up to 19 days while assessing responses in physiology, gene expression, and shoot metabolome. Results revealed 50% mortality after 9.3 and 15.9 days of submergence in intolerant Frument and tolerant Jackson, respectively, and significantly higher growth in Jackson during recovery. Frument displayed faster leaf degradation as evident from leaf tissue porosity, chlorophylla, and metabolomic fingerprinting. Surprisingly, shoot soluble carbohydrates, starch, and individual sugars declined to similarly low levels in both cultivars by day 5, showing that cultivar Jackson tolerated longer periods of low shoot carbohydrate levels than Frument. Moreover, intolerant Frument showed higher levels of phytol and the lipid peroxidation marker malondialdehyde relative to tolerant Jackson. Consequently, we propose to further investigate the role of ethylene sensitivity and deprivation of reactive O2 species in submerged wheat. [ABSTRACT FROM AUTHOR]

Long-term trials are established in order to explore and observe plant and soil interrelationships in situ. Long-term trials can be described as live instruments providing ceteris paribus conditions in temporal sequences. This review provides an introduction to major long-term trials in Hungary and in other parts of the world. It gives a brief summary of the origins of plant nutritional research, beginning with some data from Homer and the willow tree experiment of van Helmont, as well as the discovery of physiological processes by von Liebig, Lawes and Boussingault. The most profound long-term trials, like the Orto Botanico in Padova, the Linné Garden in Uppsala and the Broadbalk in Rothamsted are presented in the paper. The agronomic, educational and scientific benefits of the major Hungarian long-term trials are also discussed, from Westsik (1929) to Martonvásár and the National Plant Nutrition Trials (OMTK) set up in 1963. There is a list of experimental sites giving information on the most important recent long-term trial locations and their activities. [ABSTRACT FROM AUTHOR]

We present a high throughput crop physiology condition monitoring system and corresponding monitoring method. The monitoring system can perform large-area chlorophyll fluorescence imaging and multispectral imaging. The monitoring method can determine the crop current condition continuously and non-destructively. We choose chlorophyll fluorescence parameters and relative reflectance of multispectral as the indicators of crop physiological status. Using tomato as experiment subject, the typical crop physiological stress, such as drought, nutrition deficiency and plant disease can be distinguished by the monitoring method. Furthermore, we have studied the correlation between the physiological indicators and the degree of stress. Besides realizing the continuous monitoring of crop physiology, the monitoring system and method provide the possibility of machine automatic diagnosis of the plant physiology. [ABSTRACT FROM AUTHOR]

Tef ( Eragrostis tef (Zucc.) Trotter) is important for Ethiopian food security and a significant source of income for smallholder farmers in Ethiopia. In industrialized nations, tef is becoming a popular health food due to its lack of gluten and high nutritional value. Though tef is an important crop within Ethiopia, research on the crop has been limited. Crop models are an important tool for assessing food security, the effectiveness of management practices, and the impacts of climate change on crop production. The only existing crop models for tef are the FAO-AEZ crop growth simulation model, and the FAO AquaCrop model, which focuses on water limited crop production. The FAO AEZ model only produces final yields, which limits its applicability. The AquaCrop model has been validated using data from northern Ethiopia under current climate conditions without nitrogen limitations. As tef production spreads across the world, and Ethiopia suffers from soil fertility depletion and climate change, there is a need for a more comprehensive tef model. Tef, a short-day C4 crop, shows a high level of genetic diversity, resulting in large variation in water use, water use efficiency, growing season length, and even photosynthetic rate across cultivars. Tef quickly reaches a closed canopy, resulting in a higher early-season water use efficiency than wheat (C3 crop) or sorghum (C4 crop). Lodging is a significant yield limitation in tef, and is often exacerbated by fertilizer applications. There are several areas of tef research that have limited, or no, published data, especially on a field level, which will hinder future tef model development. These areas include the effects of temperature on photosynthesis and phenology, the effects of heat stress on senescence, the effects of elevated atmospheric CO 2 on photosynthesis and transpiration, and a field level lodging model. By combining relevant information from other crops with the available tef literature, however, it should be possible to create a tef crop model prototype. [ABSTRACT FROM AUTHOR]

Hyperspectral imaging sensors are promising tools for monitoring crop plants or vegetation in different environments. Information on physiology, architecture or biochemistry of plants can be assessed non-invasively and on different scales. For instance, hyperspectral sensors are implemented for stress detection in plant phenotyping processes or in precision agriculture. Up to date, a variety of non-imaging and imaging hyperspectral sensors is available. The measuring process and the handling of most of these sensors is rather complex. Thus, during the last years the demand for sensors with easy user operability arose. The present study introduces the novel hyperspectral camera Specim IQ from Specim (Oulu, Finland). The Specim IQ is a handheld push broom system with integrated operating system and controls. Basic data handling and data analysis processes, such as pre-processing and classification routines are implemented within the camera software. This study provides an introduction into the measurement pipeline of the Specim IQ as well as a radiometric performance comparison with a well-established hyperspectral imager. Case studies for the detection of powdery mildew on barley at the canopy scale and the spectral characterization of Arabidopsis thaliana mutants grown under stressed and non-stressed conditions are presented. [ABSTRACT FROM AUTHOR]

Faidherbia albida parklands cover a large area of the Sudano-Sahelian zone of Africa, a region that suffers from soil fertility decline, food insecurity and climate change. The parklands deliver multiple benefits, including fuelwood, soil nutrient replenishment, moisture conservation, and improved crop yield underneath the canopy. Its microclimate modification may provide an affordable climate adaptation strategy which needs to be explored. We carried out an on-farm experiment for three consecutive seasons in the Ethiopian Central Rift Valley with treatments of Faidherbia trees with bare soil underneath, wheat grown beneath Faidherbia and wheat grown in open fields. We tested the sensitivity of wheat yield to tree-mediated variables of photosynthetically active radiation (PAR), air temperature and soil nitrogen, using APSIM-wheat model. Results showed that soil moisture in the sub-soil was the least for wheat with tree, intermediate for sole tree and the highest for open field. Presence of trees resulted in 35–55% larger available N close to tree crowns compared with sole wheat. Trees significantly reduced PAR reaching the canopy of wheat growing underneath to optimum levels. Midday air temperature was about 6 °C less under the trees than in the open fields. LAI, number of grains spike −1 , plant height, total aboveground biomass and wheat grain yield were all significantly higher (P < 0.001) for wheat associated with F. albida compared with sole wheat. Model-based sensitivity analysis showed that under moderate to high rates of N, wheat yield responded positively to a decrease in temperature caused by F. albida shade. Thus, F. albida trees increase soil mineral N, wheat water use efficiency and reduce heat stress, increasing yield significantly. With heat and moisture stress likely to be more prevalent in the face of climate change, F. albida , with its impact on microclimate modification, maybe a starting point to design more resilient and climate-smart farming systems. [ABSTRACT FROM AUTHOR]

Drought is a ubiquitous abiotic factor that severely impedes growth and development of horticulture crops. The challenge postured by global climate change is the evolution of drought-tolerant cultivars that could cope with concurrent stress. Hence, in this study, biochemical, physiological and transcriptome analysis were investigated in drought-treated grapevine leaves. The results revealed that photosynthetic activity and reducing sugars were significantly diminished which were positively correlated with low stomatal conductance and CO 2 exchange in drought-stressed leaves. Further, the activities of superoxide dismutase, peroxidase, and catalase were significantly actuated in the drought-responsive grapevine leaves. Similarly, the levels of abscisic acid and jasmonic acid were also significantly increased in the drought-stressed leaves. In transcriptome analysis, 12,451 differentially-expressed genes (DEGs) were annotated, out of which 8021 DEGs were up-regulated and 4430 DEGs were down-regulated in response to drought stress. In addition, the genes encoding pathogen-associated molecular pattern ( PAMP ) triggered immunity ( PTI ), including calcium signals, protein phosphatase 2C, calcineurin B-like proteins, MAPKs, and phosphorylation ( FLS2 and MEKK1 ) cascades were up-regulated in response to drought stress. Several genes related to plant-pathogen interaction pathway ( RPM1, PBS1, RPS5, RIN4, MIN7, PR1, and WRKYs ) were also found up-regulated in response to drought stress. Overall the results of present study showed the dynamic interaction of DEG in grapevine physiology which provides the premise for selection of defense-related genes against drought stress for subsequent grapevine breeding programs. [ABSTRACT FROM AUTHOR]

Hyperspectral sensing can detect slight changes in plant physiology, and may offer a faster and nondestructive alternative for water status monitoring. This premise was tested in the current study using a narrow-band 'water balance index' ( WABI), which is based on independent changes in leaf water content (1500 nm) and the efficiency of the nonphotochemical quenching ( NPQ) photo-protective mechanism (531 nm)., The hydraulic, photo-protective and spectral behaviors of five important crops - grapevine, corn, tomato, pea and sunflower - were evaluated under water deficit conditions in order to associate the differences in stress physiology with WABI suitability., Rapid alterations in both leaf water content and NPQ were observed in grapevine, pea and sunflower, and were effectively captured by WABI. Apart from water status monitoring, the index was also successful in scheduling the irrigation of a vineyard, despite phenological and environmental variability. Conversely, corn and tomato displayed a relatively strict stomatal regime and/or mild NPQ responses and were, thus, unsuitable for WABI-based monitoring., WABI shows great potential for irrigation scheduling of various crops, and has a clear advantage over spectral models that focus on either of the abovementioned physiological mechanisms. [ABSTRACT FROM AUTHOR]

C4plants show higher photosynthetic capacity and resource use efficiency than C3plants. However, the genetic variations of these traits and their regulatory factors in C4plants still remain to be resolved. We investigated physiological, biochemical, and structural traits involved in photosynthesis and photosynthetic water and nitrogen use efficiencies (PWUE and PNUE) in 22 maize lines and four teosinte lines from various regions of the world. Net photosynthetic rate (PN) ranged from 32.1 to 46.5 μmol m−2s−1.PNwas positively correlated with stomatal conductance, transpiration rate, and chlorophyll, nitrogen and soluble protein contents of leaves, but not with specific leaf weight.PNwas positively correlated with the activities of ribulose-1,5-bisphosphate carboxylase/oxygenase and the C4-acid decarboxylases, NADP-malic enzyme and phosphoenolpyruvate carboxykinase, but not with the activity of phosphoenolpyruvate carboxylase. Leaf structural traits (stomatal parameters, leaf thickness, and interveinal distance) were not correlated withPN. These data suggest that physiological and biochemical traits are involved in the genetic variation ofPN, but structural traits are not directly involved. PWUE is in the lower class of values reported for C4plants, whereas PNUE is in the highest class of values reported for C4plants. PNUE was negatively correlated with leaf nitrogen content but not significantly correlated withPN. PWUE was not correlated withδ13C values of leaves, indicating difficulty in usingδ13C values as an indicator of PWUE of maize. In general, teosinte lines showed lowerPNbut higher PWUE than maize lines. [ABSTRACT FROM PUBLISHER]

Rice production needs to increase in the future in order to meet increasing demands. The development of new improved and higher yielding varieties more quickly will be needed to meet this demand. However, most rice breeding programmes in the world have not changed in several decades. In this article, we revisit the evidence in favour of using rapid generation advance (RGA) as a routine breeding method. We describe preliminary activities at the International Rice Research Institute (IRRI) to re-establish RGA on a large scale as the main breeding method for irrigated rice breeding. We also describe experiences from the early adoption at the Bangladesh Rice Research Institute. Evaluation of RGA breeding lines at IRRI for yield, flowering time and plant height indicated transgressive segregation for all traits. Some RGA lines were also higher yielding than the check varieties. The cost advantages of using RGA compared to the pedigree method were also empirically determined by performing an economic analysis. This indicated that RGA is several times more cost effective and advantages will be realized after 1 year even if facilities need to be built. Based on our experience, and previous independent research empirically testing the RGA method in rice, we recommend that this method should be implemented for routine rice breeding in order to improve breeding efficiency. [ABSTRACT FROM PUBLISHER]

Production of bioethanol from rice straw has attracted attention from the point of effective use of agricultural residue. Starch content is an important determinant for bioethanol production from rice straw. The overexpression ofCO2-responsive CCT protein(CRCT), which is the positive regulator of starch synthesis in vegetative organs, notably increased the starch content in rice straw. To produce the bioethanol from rice straw, the dilute acid pretreatment is a general pretreatment method. Importantly, the glucose yields in liquid hydrolyzate after dilute acid pretreatment was markedly increased in theCRCToverexpression lines compared with non-transgenic rice. In addition, the overexpression ofCRCTenhanced the biomass production. In contrast,CRCTdid not affect on the glucose yields from cellulose in acid-insoluble residue obtained after dilute acid pretreatment. With respect to byproduct in liquid hydrolyzate which inhibits the fermentation, the formic acid content was increased, whereas the furfural, 5-hydroxymethylfurfural and acetic acid contents were unchanged by the overexpression ofCRCT. These results demonstrate that genetic engineering ofCRCTis an effective method to increase the bioethanol production from rice straw. [ABSTRACT FROM PUBLISHER]

To explore the zinc stress response in eddo, plants were grown for 15 d in hydroponic solutions containing 1 (control), 200, and 1000 μM zinc, and the hydathode function and changes in the contents of various elements in these plants were investigated. Under 1000 μM zinc, the dry weights of leaf blades and roots are decreased by 17 and 42%, respectively. The zinc contents in leaf blades, petioles, corms, and roots increased with increasing zinc levels in the solution. The zinc content in roots was 6.57 mg g−1dry weight, which was 2.8–4.3 times higher than in other plant parts under 1000 μM zinc. These results demonstrate that the severe root damage occurring under 1000 μM zinc is due to higher zinc content in the roots. Under zinc stress, the contents of iron and copper in roots increased, but the contents of magnesium and calcium in petioles, corms, and roots, iron in leaf blades and corms, and manganese in petioles and corms decreased. In the guttation fluid, the concentrations of zinc, magnesium, and potassium increased, while the iron concentration decreased under 1000 μM zinc. Thus, elemental changes occurred in the guttation fluid as well as in different plant parts in eddo. In the 200 and 1000 μM zinc treatments, the amount of zinc eliminated via guttation was 2.8 and 8.5 times higher, respectively, than in the control. The results indicate that guttation partly contributes to the excretion of excess zinc under zinc stress conditions. [ABSTRACT FROM PUBLISHER]

Mixed cropping is a cultivation method widely practiced in tropical regions. The newly developed close mixed planting technique mitigates the flood stress of drought-adapted upland cereal species by co-growing rice (Oryza sativa) plants under field flood conditions. We tested the hypothesis that O2was transferred from rice to upland crops using the model system of hydroponic culture. To confirm the hypothesis, the phenomena of O2absorption and release by plants were evaluated in a water culture condition without soil. Experiments were conducted in a climate chamber to estimate the amount of O2released from the roots of rice and pearl millet (Pennisetum glaucum) under both O2-rich (20.0 ± .0% conc. in phase I) and O2-free dark (.8 ± .0% conc. in phase II) conditions. The total O2change (between the two phases) in a single planting of rice and pearl millet was significantly higher than that of the mixed planting of rice and pearl millet, which indicated that O2was transferred from rice to pearl millet under a water culture condition. The result indicated that approximately 7 μM O2 g fresh root weight−1 h−1was transferred between the two plant species. O2transfer was confirmed between the two plant species in a mix cultured in water, implying its contribution to the phenomenon that improved the physiological status of drought-adapted upland crops under field flood conditions. [ABSTRACT FROM PUBLISHER]

Drought stress which often occurs during early growth stage is one constraint in sugarcane production. In this study, the response of sugarcane to drought and nitrogen application for physiological and agronomical characteristics was investigated. Two water regimes (well-watered and drought stress from 60 to 120 day after transplanting) and four nitrogen levels (0, 4.4, 8.8 and 13.2 g pot−1equivalent to 0, 90, 180 and 270 kg ha−1, respectively) were assigned in a Split-plot design with three replications. The results showed that photosynthetic responses to light intensity and intercellular CO2concentrations of sugarcane were different between fertilized and non-fertilized treatments. Photosynthetic rates of 180 and 270 N treatments, normally, were significantly higher than that of 90 N, but not significant at drought conditions. Photosynthetic rates of 0 N treatment were the lowest under both conditions. Higher nitrogen application supported higher photosynthetic rate, stomatal conductance, and chlorophyll content because of higher nitrogen concentration accumulated into the leaf. Drought significantly reduced the potential photosynthetic rate, stomatal conductance, SPAD, leaf area, and biomass production. Higher nitrogen applications with larger root system could support higher photosynthetic activities to accumulate more dry mass. Strong positive coefficient between photosynthetic and biomass nitrogen use efficiency and drought tolerance index may suggest that higher nitrogen use efficiency could help plants have higher ability to tolerate drought stress. [ABSTRACT FROM PUBLISHER]

Seed coating with molybdenum compounds improves seedling establishment for rice, wheat, barley, and soybean when such seeds were sown under flooded conditions. Tungsten belongs to the same chemical group as molybdenum in the periodic table, and similar to molybdenum, inhibits the generation of sulfide ions. Here, the effects of tungsten and molybdenum containing seed coatings on seedling establishment under flooded conditions were compared using rice, wheat, barley, and soybean. In rice, the effects of tungsten compounds on seedling establishment varied. Tungsten trioxide had little effect but tungstic acid and ammonium phosphotungstate significantly improved seedling establishment when the amounts were at least .1–.2 mol W kg−1. Although the effect of tungsten coating varied depending on the compound used, ammonium phosphotungstate, along with other tungsten compounds, improved seedling establishment in a manner comparable with that of molybdenum compounds. For wheat and barley, ammonium phosphotungstate treatment resulted in a significant increase in establishment that was only slightly less than the results observed using molybdenum compounds. Tungstic acid and ammonium phosphotungstate treatments improved soybean establishment in a significant manner that was comparable with those of molybdenum compounds. Collectively, these results suggest that tungsten compounds, as well as molybdenum compounds, improve seedling establishment under flooded conditions. [ABSTRACT FROM PUBLISHER]

The effect of soil exchangeable (plant-available) potassium (ExK) content on cesium (Cs) absorption and translocation in buckwheat was evaluated in a field contaminated with radioactive Cs (134Cs and137Cs, RCs) in 2013. The RCs concentration in buckwheat was significantly positively correlated with the naturally occurring stable Cs (133Cs, SCs) concentration, and was lower at higher soil ExK content. The RCs and SCs were actively absorbed by buckwheat until the flowering stage. The soil ExK content was significantly negatively correlated with soil exchangeable RCs and SCs (ExRCs and ExSCs) concentrations. Greater RCs and SCs absorption by buckwheat in soils with low ExK contents was mainly due to higher soil ExRCs and ExSCs concentrations. Reproductive organs showed the largest differences in SCs concentration between low-ExK and high-ExK plots. The root–shoot and shoot–reproductive organs translocations of SCs markedly decreased with increasing soil ExK content. In the root–shoot and shoot–reproductive organs translocations, the discrimination of SCs and K decreased with decreasing soil ExK content. Our main findings were as follows: (1) because RCs are mainly taken up at the earlier growth stage, potassium should be applied as a basal fertilizer to decrease the RCs concentration in buckwheat; (2) lower soil ExK content led to higher soil ExRCs concentrations, resulting in greater RCs absorption by buckwheat; (3) the high Cs absorption and translocation and weaker discrimination between Cs and K in low ExK content soil may be due to the expression of K transporter(s) with weak discrimination between Cs and K. [ABSTRACT FROM PUBLISHER]

The objective of the present study was to investigate the changes of growth related aspects of seedlings after being exposed to Wi-Fi radiation. Experiment was carried out by exposing seedlings to radiation from a Wi-Fi router. The test seedlings and the control were subjected to the same environment during four weeks. The results showed that corn seedlings when exposed to Wi-Fi radiation grew faster and have shoot length and stem thickness significantly larger than the other control. On the other hand basils and eggplants, both exposed and not exposed to Wi-Fi radiation, were found with no significant effects on the shoot length and stem thickness. Moreover Wi-Fi radiation significantly reduced the fresh weight of corns and basils, whereas eggplants were not affected. Furthermore Wi-Fi radiation significantly increased the dry weight of eggplants, whereas corns and basils were not affected. Finally, the results showed that Wi-Fi radiation significantly decreased the water content of three tested seedlings. The study concluded that the Wi-Fi radiation may alter growth related characters of seedlings. [ABSTRACT FROM AUTHOR]

Microplastic residues pose one of the most serious environmental problems in areas where plastic mulch is used extensively. Microplastic pollution has potentially serious consequences for ecosystems and human health. Several studies have analyzed microplastics in greenhouses or laboratory climate-controlled chambers; however, field studies evaluating the effects of different microplastics on different crops in extensive farming are limited. Therefore, we selected three major crops, Zea mays (ZM, monocotyledon), Glycine max (GM, dicotyledon, aboveground-bearing), and Arachis hypogaea (AH, dicotyledon, belowground-bearing) and investigated the effect of adding polyester microplastics (PES-MPs) and polypropylene microplastics (PP-MPs). Our results demonstrate that PP-MPs and PES-MPs decreased the soil bulk density of ZM, GM, and AH. Regarding soil pH, PES-MPs increased the soil pH of AH and ZM, whereas PP-MPs decreased the soil pH of ZM, GM, and AH compared to controls. Intriguingly, different coordinated trait responses to PP-MPs and PES-MPs were observed in all crops. In general, commonly measured parameters of AH, such as plant height, culm diameter, total biomass, root biomass, PSII maximum photochemical quantum yield (Fv/Fm), hundred-gain weight, and soluble sugar tended to decrease under PP-MPs exposure; however, some indicators of ZM and GM increased under PP-MPs exposure. PES-MPs had no obviously adverse influence on the three crops, except for the biomass of GM, and even significantly increased the chlorophyll content of AH, specific leaf area, and soluble sugar of GM. Compared with PES-MPs, PP-MPs have serious negative effects on crop growth and quality, especially AH. The findings of the present study provides evidence for evaluating the impact of soil microplastic pollution on crop yield and quality in farmland and lay a foundation for future investigations on the exploration of MP toxicity mechanisms and adaptability of different crops to microplastics. [Display omitted] • PP-MPs and PES-MPs altered soil bulk density and pH. • MP-driven changes in plant traits were dependent on MP type and species. • PP-MPs reduced total biomass of AH, GM, and ZM. • PES-MPs only reduced total biomass of GM. • PP-MPs had greater impacts on crops compared to PES-MPs, especially AH. [ABSTRACT FROM AUTHOR]