Leaf micromorphology and sugar may contribute to differences in drought tolerance for two apple cultivars.
Leaf micromorphology and sugar may contribute to differences in drought tolerance for two apple cultivars.
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DOI：
10.1016/j.plaphy.2014.04.012
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发表时间：
2014-07
期刊：
影响因子：
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通讯作者：
Shan Wu;D. Liang;F. Ma
中科院分区：
文献类型：
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作者：
Shan Wu;D. Liang;F. Ma
苹果树(Malushome ticaL.)在夏季经常暴露在严重的水分压力下。我们测定了耐旱‘秦冠’和耐旱‘长野富士’两个品种的叶片中非结构性碳水化合物(NC)水平在突发性水分亏缺10d时的变化。从气体交换和抗氧化酶活性两个方面考察了其光合作用表现。用嫁接到湖北海棠(Malus hupehensis(Pamp.)雷德。砧木：1)施水75%田间持水量(对照，对照)；2)保留灌溉，以达到75%田间持水量(FC)30-75%(处理，T)。在实验的第0、1、2、4、6和10天，我们记录了净CO2同化、气孔导度、叶片蒸腾速率和胞间CO2浓度。所有这些参数都显示，在两种压力情景下，植物的数量都出现了下降，尽管在秦冠中下降的幅度没有那么大。光合作用速率降低的主要原因是气孔关闭。在两个品种中，水分胁迫诱导了NC的积累，尤其是山梨醇，这表明这种多元醇具有渗透调节作用。秦冠的山梨醇水平上升幅度要大得多。同样，超氧化物歧化酶和过氧化物酶活性之间的互作也因品种而异。与‘长野富士’相比，‘秦冠’的丙二醛浓度低得多，且与高的Suc/NC比值密切相关。扫描电子显微镜观察到‘秦冠’的抗旱表观结构。总体而言，我们的外部和内部测试结果表明，‘秦冠’比‘长野富士’更耐旱。
Apple trees (MalusdomesticaL.) are often exposed to severe water stress in the summertime. We determined how levels of nonstructural carbohydrates (NC) changed in the leaves of two cultivars – drought-tolerant ‘QinGuan’ and drought-sensitive ‘NaganoFuji’ – when plants were subjected for 10 d to a sudden water deficit. Photosynthetic performance was investigated in terms of gas exchange and antioxidant enzyme activity. Two separate irrigation scenarios were tested with one-year-old plants grafted ontoMalus hupehensis(Pamp.) Rehd. rootstock: 1) water applied to 75% field capacity (FC) (Control, CK) and 2) irrigation withheld to achieve <75% FC ranging from 30 to 75% (Treatment, T). At Days 0, 1, 2, 4, 6, and 10 of the experiment, we recorded net CO2assimilation, stomatal conductance, leaf transpiration rates, and intercellular CO2concentrations. All of those parameters showed decreases in plants from both stress scenarios, although those declines were not as dramatic in ‘QinGuan’. The photosynthetic rate reduced primarily because of stomatal closure. In both cultivars, water stress induced the accumulation of NC, especially sorbitol, suggesting that this polyol has a role in osmoregulation. The rise in sorbitol levels was much steeper in ‘QinGuan’. Likewise, the interaction between superoxide dismutase and peroxidase activities varied between cultivars. In ‘QinGuan’, the malondialdehyde concentration was much lower and more closely correlated with a high Suc/NC ratio when compared with ‘NaganoFuji’. Scanning electron microscopy revealed a drought-resisting apparent structure in ‘QinGuan’. Overall, our results from both external and internal examinations demonstrated that ‘QinGuan’ is more drought-tolerant than ‘NaganoFuji’.