Film antitranspirants (e.g. di-1-p-menthene) and metabolic antitranspirants (e.g. exogenous ABA) can be used to protect grain crops from drought, particularly during reproductive development. Here, we compared effects of di-1-p-menthene (1.0 L/ha) and exogenous ABA (100 µM) on well-watered and droughted spring wheat in two glasshouse experiments. Progressive drought was imposed in the first experiment, controlled drought in the second, both from flag leaf emergence. Antitranspirants were applied at flag leaf emergence, except in the controlled drought experiment where additional ABA applications were made at four further stages up to anthesis-complete. Measurements were taken for endogenous ABA, stomatal conductance and photosynthesis during reproductive development, and yield components at maturity. Both progressive and controlled drought elevated leaf ABA, less so in di-1-p-menthene-treated plants, whereas in exogenous ABA-treated plants leaf ABA was elevated further. Overall, both antitranspirants improved yield under reproductive-stage drought, more so for controlled drought. Grain yield was negatively associated with reproductive-stage leaf ABA concentration except that raising leaf ABA concentration with multiple exogenous ABA applications was associated with high yield. In conclusion, both antitranspirants generally reduced effects of reproductive-stage drought on yield despite having contrary effects on leaf ABA.

中文翻译：

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尽管对叶片 ABA 有不同的影响，但代谢和薄膜抗蒸腾剂都减少了干旱对小麦产量的损害

薄膜抗蒸腾剂（例如二-1-对薄荷烯）和代谢抗蒸腾剂（例如外源性ABA）可用于保护粮食作物免受干旱影响，特别是在生殖发育期间。在这里，我们比较了 di-1- p的效果在两个温室实验中，对充分浇水和干旱的春小麦进行 - 薄荷烯 (1.0 L/ha) 和外源 ABA (100 µM)。在第一个实验中施加了渐进干旱，在第二个实验中施加了控制干旱，两者都是从旗叶出现开始的。抗蒸腾剂在旗叶出苗时使用，除了在受控干旱实验中，额外的 ABA 应用在四个进一步的阶段进行，直到开花完成。对生殖发育过程中的内源ABA、气孔导度和光合作用以及成熟时的产量成分进行了测量。渐进性和控制性干旱都提高了叶片 ABA，在 di-1- p-薄荷烯处理的植物，而在外源ABA处理的植物中，叶ABA进一步升高。总体而言，两种抗蒸腾剂都提高了生殖阶段干旱下的产量，对于受控干旱更是如此。谷物产量与生育期叶片 ABA 浓度呈负相关，但通过多次外源 ABA 应用提高叶片 ABA 浓度与高产相关。总之，尽管对叶片 ABA 有相反的影响，但两种抗蒸腾剂通常都会降低生殖期干旱对产量的影响。