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Grape rain-shelter cultivation is a widely employed practice in China. At present, the most commonly used rain shelter film materials are polyvinyl chloride (PVC), polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), and polyolefin (PO). Coverlys TF150® is a woven fabric with an internal antifoggy PE coating that has not yet been popularized as a rain shelter film for grapes in China. To investigate the effects of Coverlys TF150® on grapes, we measured the microdomain environment, leaf development, and photosynthetic characteristics of 'Miguang' (Vitis vinifera × V. labrusca) under rain-shelter cultivation and performed transcriptome analysis. The results showed that Coverlys TF150® significantly reduced (p < 0.05) the light intensity, temperature, and humidity compared with PO film, increased the chlorophyll content and leaf thickness (particularly palisade tissue thickness), and increased stomatal density and stomatal opening from 10:00 to 14:00. Coverlys TF150® was observed to improve the maximum efficiency of photosystem II (Fv/Fm), photochemical quenching (qP), the electron transfer rate (ETR), and the actual photochemical efficiency (ΦPSII) from 10:00 to 14:00. Moreover, the net photosynthetic rate (Pn), intercellular CO2 concentration (Ci), stomatal conductance (Gs), and transpiration rate (Tr) of grape leaves significantly increased (p < 0.05) from 10:00 to 14:00. RNA-Seq analysis of the grape leaves at 8:00, 10:00, and 12:00 revealed 1388, 1562, and 1436 differential genes at these points in time, respectively. KEGG enrichment analysis showed the occurrence of protein processing in the endoplasmic reticulum. Plant hormone signal transduction and plant-pathogen interaction were identified as the metabolic pathways with the highest differential gene expression enrichment. The psbA encoding D1 protein was significantly up-regulated in both CO10vsPO10 and CO12vsPO12, while the sHSPs family genes were significantly down-regulated in all time periods, and thus may play an important role in the maintenance of the photosystem II (PSII) activity in grape leaves under Coverlys TF150®. Compared with PO film, the PSI-related gene psaB was up-regulated, indicating the ability of Coverlys TF150® to better maintain PSI activity. Compared with PO film, the abolic acid receptacle-associated gene PYL1 was down-regulated at all time periods under the Coverlys TF150® treatment, while PP2C47 was significantly up-regulated in CO10vsPO10 and CO12vsPO12, inducing stomatal closure. The results reveal that Coverlys TF150® alleviates the stress of high temperature and strong light compared with PO film, improves the photosynthetic capacity of grape leaves, and reduces the midday depression of photosynthesis. [ABSTRACT FROM AUTHOR]

Nitrogen (N) is the most limiting nutrient for maize, and appropriate N fertilization can promote maize growth and yield. The effect of N fertilizer rates and timings on morphology, antioxidant enzymes, and grain yield of maize (Zea mays L.) in the Loess Plateau of China was evaluated. The four N levels, i.e., 0 (N0), 100 (N1), 200 (N2), and 300 (N3) kg ha−1, were applied at two timings (T1, one-third N at sowing and two-thirds at the six-leaf stage of maize; T2, one-third applied at sowing, six-leaf stage, and eleven-leaf stage of maize). The results show that N2 and N3 significantly increased the plant height, stem and leaf dry weight, and leaf area index of maize compared with a non-N-fertilized control (N0). The net photosynthetic rate, transpiration rate, stomatal conductance, and leaf chlorophyll contents were lower, while the intercellular carbon dioxide concentration was higher for non-fertilized plants compared to fertilized plants. The activities of peroxidase (POD) and superoxide dismutase (SOD) increased with N rate, but the difference between 200 and 300 kg ha−1 was not significant; further, the isozyme bands of POD and SOD also changed with their activities. Compared with a non-N-fertilized control, N2 and N3 significantly increased grain yield by 2.76- and 3.11-fold in 2018, 2.74- and 2.80-fold in 2019, and 2.71- and 2.89-fold in 2020, and there was no significant difference between N2 and N3. N application timing only affected yield in 2018. In conclusion, 200 kg N ha−1 application increased yield through optimizing the antioxidant enzyme system, increasing photosynthetic capacity, and promoting dry matter accumulation. Further research is necessary to evaluate the response of more cultivars under more seasons to validate the results obtained. [ABSTRACT FROM AUTHOR]

In the southern Huang-Huai-Hai (HHH) region, China, maize production is frequently threatened by waterlogging at the seedling stage and by drought at the big flare stage. A two-year field experiment was performed to explore whether subsoiling (SS) in the winter wheat season could improve the photosynthetic capacity and increase the water use efficiency (WUE) of summer maize using the variety, Luyu9105. A split design was adopted in the experiment. The main plots used tillage practices, including SS and rotary tillage (RT). The subplots consisted of two irrigation methods, i.e., applied supplemental irrigation at the big flare stage (I) and no irrigation at the big flare stage (NI). The results showed that the SS treatment significantly increased soil water content (SWC) in the 40–60 cm soil layer. The SS treatment improved green leaf area index (gLAI) by 15.1%–30.2%, and enhanced the ear-leaf net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (ci) and transpiration rate (Tr), and was accompanied by an increase in the grain-filling duration (T) by 5 days and the mean grain-filling rate (Va). The SS treatment decreased the stomatal limitation (Ls), indicating that RT treatment, which was under lower SWC, led to a decrease in Pn. Applied supplemental irrigation under RT treatment was able to compensate for the growth of leaves, but could not reverse the decreasing trend in the gLAI. Ultimately, the SS treatment improved WUE by 9.1%–9.9%, and increased grain yields by 10.0%–29.3%. Therefore, this study showed that in the southern Huang-Huai-Hai Plain, which has a yellow cinnamon soil type, the practice of SS can improve the photosynthetic characteristics of leaves and WUE of rainfed summer maize. [ABSTRACT FROM AUTHOR]