Background

Abscisic acid (ABA) acts as a signaling hormone in plants against abiotic stress, but its function in energy homeostasis under heat stress is unclear.

Results

Two rice genotypes, Nipponbare (wild-type, WT) with flat leaves and its mutant high temperature susceptibility (hts) plant with semi-rolled leaves, were subjected to heat stress. We found significantly higher tissue temperature, respiration rate, and ABA and H₂O₂ contents in leaves as well as a lower transpiration rate and stomatal conductance in hts than WT plants. Additionally, increased expression of HSP71.1 and HSP24.1 as well as greater increases in carbohydrate content, ATP, NAD (H), and dry matter weight, were detected in WT than hts plants under heat stress. More importantly, exogenous ABA significantly decreased heat tolerance of hts plants, but clearly enhanced heat resistance of WT plants. The increases in carbohydrates, ATP, NAD (H), and heat shock proteins in WT plants were enhanced by ABA under heat stress, whereas these increases were reduced in hts plants.

Conclusion

It was concluded that ABA is a negative regulator of heat tolerance in hts plants with semi-rolled leaves by modulating energy homeostasis.

中文翻译：

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脱落酸通过提高叶温和调节能量稳态来负调节卷叶米的耐热性

 背景

脱落酸（ABA）在植物中充当对抗非生物胁迫的信号激素，但其在热胁迫下能量稳态中的功能尚不清楚。

 结果

两种水稻基因型，即具有平叶的日本晴（野生型，WT）及其具有半卷叶的突变体高温敏感性（ hts ）植物，受到热胁迫。我们发现，与野生型植物相比，hts 的组织温度、呼吸速率以及叶片中的 ABA 和 H ₂ O ₂含量显着较高，而hts的蒸腾速率和气孔导度则较低。此外，在热胁迫下，与hts植物相比，WT 植物中检测到HSP71.1和HSP24.1表达增加，碳水化合物含量、ATP、NAD (H) 和干物质重量增加更大。更重要的是，外源ABA显着降低了hts植物的耐热性，但明显增强了WT植物的耐热性。在热胁迫下，ABA 增强了 WT 植物中碳水化合物、ATP、NAD (H) 和热休克蛋白的增加，而hts植物中的这些增加则减少了。

 结论

结论是，ABA 通过调节能量稳态，对半卷叶hts植物的耐热性具有负调节作用。