NaCl胁迫对5种柑橘砧木生长及生理特性的影响

以枳、枳橙、沃尔卡默柠檬、硬枝香橙和宜昌橙的老熟幼苗为试材,在NaCl胁迫下,评价这5种柑橘砧木的生长及生理特性.结果发现, NaCl胁迫处理21 d以后,沃尔卡默柠檬的植株和叶片未出现明显不良症状,表现出较强的抗盐性,而枳橙、硬枝香橙抗盐性次之,宜昌橙和枳对盐比较敏感;分析NaCl胁迫过程中叶片可溶性蛋白、脯氨酸质量分数以及过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化歧化酶(SOD)的活性变化,发现5种砧木叶片中可溶性蛋白质量分数变化不大,脯氨酸质量分数变化明显,其中枳、枳橙和沃尔卡默柠檬叶片的脯氨酸质量分数显著增加,枳、枳橙和沃尔卡默柠檬的CAT活性、枳和沃尔卡默柠檬叶片中POD活性均随着NaCl胁迫时间增加呈现显著减少趋势,而枳、枳橙、沃尔卡默柠檬和硬枝香橙的SOD活性则均随着盐胁迫处理时间增加呈现出显著上升的变化.综合分析发现各砧木抗盐性差异与各氧化酶的活性变化关联不大,推测沃尔卡默柠檬抗盐性较强可能与其根系有较强的排盐能力或者叶片有较强的离子区划能力相关.

Evaluation of Salinity Tolerance in Five Citrus Rootstock Seedlings

This research was conducted to compare salt-tolerance of five citrus rootstock seedlings:trifoliate, Carrizo Citrange (orange/trifoliate hybrid), Volkamer (lemon), Yingzhi orange and Yichang orange. After exposing to salinity for 21 days, Volkamer plants and leaves were normal without visual injury and change in the chlorophyll meter (SPAD) reading; however, Yichang orange and trifoliate plants were extremely sensitive to salinity; and Carrizo Citrange and Yingzhi orange plants were in between. Salinity stress treatment resulted in no discernible change in insoluble protein content and considerable change in proline content of the leaf samples, and the increase in proline content was statistically significant in the leaves of trifoliate, Carrizo Citrange and Volkamer. With the extension of the duration of salt stress, catalase (CAD) activity in the leaves of trifoliate, Carrizo Citrange and Volkamer and peroxidase (POD) activity in the leaves of trifoliate and Volkamer showed an obvious decreasing trend, while superoxide dismutase (SOD) activity exhibited an obvious increasing trend in trifoliate, Carrizo Citrange, Volkamer and Yingzhi samples. Salt-tolerance of the rootstocks studied did not seem closely associated with the activity of their oxidation enzymes. The relatively high salt stress of Volkamer was speculated to be associated with the great salt removal capacity of its root system or/and with its ability to limit the accumulation of sodium and chlorine ions in the leaves.