Abstract One plant trait that has been developed in several crop species to increase the effectiveness in water use through the cropping season is limited-transpiration under elevated atmospheric vapor pressure deficit (VPD). This trait allows water conservation early in the season so that there is more soil water available late in the season for sustained physiological activity during seed development. In sweet corn (Zea mays L. saccharata), where the quality of the kernels is important, this trait could prove to be especially beneficial. The background objective of this study was to explore 16 sweet corn cultivars for expression of the limited-transpiration trait. It was found at 32 °C that 13 of the 16 cultivars expressed the trait. It was found in a subset of eight of these cultivars, however, only half retained the limited-transpiration trait at 38 °C. The additional objectives were to explore the hypotheses that expression of the limited-transpiration trait was related to plant hydraulic conductance, and to the abundance of silver-sensitive aquaporins in the leaves. In cultivars that lost expression of the limited-transpiration trait at 38 °C there were large increases in plant hydraulic conductance at 38 °C as compared to 32 °C. Abundance of silver-sensitive aquaporins was related to the transpiration rate under low VPD conditions. That is, those cultivars with more abundant silver-sensitive aquaporins had greater transpiration rates as a result of greater stomatal conductance. These results showed that while expression of the limited-transpiration trait in sweet corn at 32 °C was common, differences in expression of the trait at 38 °C were observed due to differences in plant hydraulic conductance and stomatal conductance.

中文翻译：

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甜玉米品种在高蒸汽压亏缺和高温下有限蒸腾速率的基础

摘要 已在几种作物物种中开发以提高整个作物季节的水分利用效率的一种植物性状是在升高的大气蒸气压亏缺 (VPD) 下的有限蒸腾作用。这种特性允许在季节早期进行节水，以便在季节后期有更多的土壤水可用于种子发育期间的持续生理活动。在甜玉米 (Zea mays L. saccharata) 中，籽粒的质量很重要，这种特性可能被证明是特别有益的。本研究的背景目标是探索 16 个甜玉米品种表达有限蒸腾性状。发现在 32 °C 时，16 个品种中有 13 个表达了该性状。然而，在这些品种的八个子集中发现了它，只有一半在 38 °C 时保留了有限蒸腾特性。额外的目标是探索有限蒸腾性状的表达与植物水力传导以及叶片中银敏感水通道蛋白的丰度有关的假设。在 38°C 时失去有限蒸腾性状表达的栽培品种中，与 32°C 相比，38°C 时植物水力传导度显着增加。银敏感水通道蛋白的丰度与低 VPD 条件下的蒸腾速率有关。也就是说，那些具有更丰富的银敏感水通道蛋白的品种由于更大的气孔导度而具有更高的蒸腾速率。这些结果表明，虽然在 32 °C 下甜玉米中有限蒸腾性状的表达很常见，