Chen Ruixia, Xu Quanyue, Wan Junliang, Jiang Nan, Ma Juanjuan, Zheng Lijian
College of Water Resources Science and Engineering, Taiyuan University of Technology, Taiyuan, China.
Shanxi Key Laboratory of Cooperative Utilization for Basin Water Resources, Taiyuan, China.
Front Plant Sci. 2024 Dec 18;15:1516824. doi: 10.3389/fpls.2024.1516824. eCollection 2024.
Accurate diagnosis of the water status of fruit trees is a prerequisite for precise irrigation. Measurement of leaf turgor pressure provides a means to explore the water utilization mechanisms of fruit trees and their responses to water stress. However, there are few studies on the use of daily minimum leaf turgor pressure (Ppmax) to indicate water information in apple tree.
We monitored Ppmax, stem flow rate (Vstem), leaf water potential, soil water, and the main meteorological factors under two drip irrigation levels (fully irrigated and under-irrigated) to elucidate the temporal dynamics of the daily leaf turgor minimum of apple trees and diagnose the water status of fruit trees.
The results showed that soil water deficiency could reduce leaf turgor pressure and increase Ppmax. In both years, the signal intensity and sensitivity of Ppmax were better than those of Vstem, and the sensitivity was 3.31 and 2.94 times of Vstem, respectively. Compared to Ppmax, Vstem had a higher correlation with meteorological factors and was more affected by meteorological conditions, independent of irrigation treatment. Ppmax was significantly negatively correlated with soil and leaf water potential, and its correlation coefficient was 2.58-4.89 times higher than that between Vstem and both.
These results not only enhance our understanding of the water regulation strategies employed by apple trees under drought conditions but also provide a theoretical foundation for developing efficient water-saving practices and precision irrigation strategies for fruit trees.
准确诊断果树的水分状况是精准灌溉的前提。叶片膨压的测量为探索果树水分利用机制及其对水分胁迫的响应提供了一种手段。然而，关于利用日最小叶片膨压（Ppmax）来指示苹果水分信息的研究较少。
我们监测了两种滴灌水平（充分灌溉和欠灌溉）下的Ppmax、树干液流速率（Vstem）、叶片水势、土壤水分和主要气象因子，以阐明苹果树日最小叶片膨压的时间动态，并诊断果树的水分状况。
结果表明，土壤水分亏缺会降低叶片膨压并增加Ppmax。在这两年中，Ppmax的信号强度和敏感性均优于Vstem，其敏感性分别是Vstem的3.31倍和2.94倍。与Ppmax相比，Vstem与气象因子的相关性更高，且受气象条件影响更大，与灌溉处理无关。Ppmax与土壤和叶片水势显著负相关，其相关系数比Vstem与两者之间的相关系数高2.58 - 4.89倍。
这些结果不仅增进了我们对干旱条件下苹果树水分调节策略的理解，也为制定果树高效节水措施和精准灌溉策略提供了理论基础。
