干旱胁迫对2种苹果砧木生理及光合特性的影响

Effects of Drought Stress on Physiological and Photosynthetic Characteristics of Two Apple Rootstocks

采用盆栽试验法研究干旱胁迫对2种苹果砧木生理及光合特性的影响。结果表明：随着干旱胁迫程度的加深，平顶海棠叶片净光合速率（Pn）、蒸腾速率（Tr）及气孔导度（Gs）呈下降趋势，而美国黄海棠则均呈先升后降趋势；2种砧木根系活力和叶片中丙二醛（MDA）含量均呈先升后降趋势；可溶性蛋白含量在轻度胁迫时（土壤相对含水量SRW为50％）-q对照的差异不显著，中、重度干旱胁迫下（SRW为20％～35％）则极显著降低。平顶海棠叶片中的超氧化物歧化酶（SOD）和过氧化物酶（POD）活性在各胁迫处理下的差异不显著，而美国黄海棠则随干旱胁迫程度加深SOD活性呈先降后升、POD活性则为先升后降的变化趋势。各指标的变化均表现为平顶海棠的变化幅度大于美国黄海棠。综合各项测定指标及植株的形态表现认为，美国黄海棠的抗旱能力高于平顶海棠。

Two apple rootstocks grown in pots were studied to understand the effects of drought stress on physiological and photosyntbetic characteristics of the two Malus species. The results showed that with the increasing of drought stress, the Pn, Tr and Gs of Malus robusta had decreasing tendency but that of American Malus spectabilis increased instead at the beginning and decreased afterwards. Root activity and MDA content in the leaves first increased and then declined in the both two apple rootstocks. There was no significant difference between the treatment and CK under mild drought stress （SRW 50%） in soluble protein content which in the treatment was very significant lower than CK under moderate and severe drought stresses （SRW 20%-35%）. Both SOD activity and POD activity of Maius robusta Rehd had no significant difference between each treatment. SOD activity of American Malus spectabilis decreased at the beginning and increased afterwards but POD activity of it first increased and then declined instead. The changes of all the tested indexes of Maius robusta were greater than that of American Maius spectabilis. According to comprehensive analysis and the plant growth in the field, American Malus spectabilis could be considered as a plant with stronger drought tolerance than Maius rob us ta.