In this study we analysed the influence of drought stress on the leaf morphological characteristics, osmotic adjustment substances, antioxidant enzymes, and resistance-related photosynthetic physiological indices of Harumi tangor plants grafted onto Poncirus trifoliata (Pt), Citrus junos (Cj), and Citrus tangerine (Ct). The leaf relative water content and leaf area of the three rootstocks decreased with increasing drought stress, with the smallest decrease in Cj. The relative conductivity and malondialdehyde content increased with increasing drought stress. Proline, total soluble sugar, soluble protein, and activities of superoxide dismutase, ascorbate peroxidase, and catalase increased with drought stress but decreased under severe drought stress, with Cj exhibiting the greatest increase in enzyme activity. The net photosynthetic rate, stomatal conductance, transpiration rate, and chlorophyll a and b content were all lower than those of the control, whereas intercellular CO₂ concentration increased with increasing drought stress. The initial fluorescence and maximal quantum yield of PSII were approximately equal for all rootstocks but increased with increasing drought stress severity. The combined analysis of physiological indicators, membership function, and principal components indicated that the drought resistance of grafted H. tangor decreased in the order Cj > Ct > Pt.

在这项研究中，我们分析了干旱胁迫对嫁接到三叶草（Pt），柑桔（Cj）和柑桔的Harumi tangor植物的叶片形态特征，渗透调节物质，抗氧化酶以及与抗性相关的光合生理指标的影响。柑橘（Ct）。三种砧木的叶片相对含水量和叶面积随干旱胁迫的增加而降低，Cj的降低最小。相对电导率和丙二醛含量随干旱胁迫的增加而增加。脯氨酸，总可溶性糖，可溶性蛋白以及超氧化物歧化酶，抗坏血酸过氧化物酶和过氧化氢酶的活性随干旱胁迫而增加，但在严重干旱胁迫下降低，其中Cj表现出最大的酶活性增加。净光合速率，气孔导度，蒸腾速率以及叶绿素a和b含量均低于对照，而细胞间CO ₂随着干旱胁迫的增加，浓度增加。对于所有砧木，PSII的初始荧光和最大量子产率均大致相同，但随着干旱胁迫严重程度的增加而增加。生理指标，隶属函数和主要成分的综合分析表明，嫁接的H. tangor的抗旱性按Cj> Ct> Pt的顺序降低。