Gong Lei, Hua Ye, Su Yun-Yun, Zhang Bo, Yao Li-Ting, Alharbi Basmah M, Hasan Md Mahadi
School of Agriculture and Bioengineering, Longdong University, Qingyang, China.
Gansu Key Laboratory of Protection and Utilization for Biological Resources and Ecological Restoration, Qingyang, China.
Front Plant Sci. 2025 Jun 17;16:1570821. doi: 10.3389/fpls.2025.1570821. eCollection 2025.
In response to drought stress, abscisic acid (ABA) plays a crucial role in regulating stomatal closure in both leaf and floral tissues. Studies on stomatal regulation have primarily focused on the leaves of vascular plants, but stomatal regulation of flowers remains underexplored. The current study was conducted on the petals of 'Ma Lin' daylily ( Baroni) to assess the morphological characteristics of petal stomata, stomatal aperture, gas exchange, and the mechanisms of ABA signaling in response to treatments with ABA-related chemicals and their corresponding scavengers. The study showed that stomata are primarily located in the lower epidermis of the petals, arranged in a strip near the central vein, and exhibit relatively low density; the guard cells contain a large number of chloroplasts. Exogenous ABA induced stomatal closure in the petal stomata, and the gas exchange assay indicated that stomatal conductance decreased when exogenous ABA was introduced into the transpiration stream. The stomatal aperture assay revealed a 32.78% decrease following a 10 µM ABA treatment. Furthermore, both hydrogen peroxide (HO) and nitric oxide (NO) were involved in the ABA-induced stomatal closure process, with HO acting as an upstream component of NO. Overall, these results suggest that physiologically active stomatal control is present in the flower of 'Ma Lin' daylily under drought stress, consistent with the regulation observed in leaf stomata.
在干旱胁迫响应中，脱落酸（ABA）在调节叶片和花器官组织的气孔关闭方面发挥着关键作用。关于气孔调节的研究主要集中在维管植物的叶片上，而花的气孔调节仍未得到充分探索。本研究以‘马蔺’萱草（Baroni）的花瓣为材料，评估花瓣气孔的形态特征、气孔孔径、气体交换以及ABA信号转导机制对ABA相关化学物质及其相应清除剂处理的响应。研究表明，气孔主要位于花瓣下表皮，沿中央叶脉呈带状排列，密度相对较低；保卫细胞含有大量叶绿体。外源ABA诱导花瓣气孔关闭，气体交换测定表明，当外源ABA引入蒸腾流时气孔导度降低。气孔孔径测定显示，10 μM ABA处理后气孔孔径下降了32.78%。此外，过氧化氢（HO）和一氧化氮（NO）均参与ABA诱导的气孔关闭过程，其中HO作为NO的上游成分。总体而言，这些结果表明，干旱胁迫下‘马蔺’萱草花中存在生理活性气孔控制，这与叶片气孔中观察到的调节一致。
