旗叶蜡质含量不同小麦近等基因系的抗旱性

Drought Resistance of Wheat NILs with Different Cuticular Wax Contents in Flag Leaf

于2013—2014和2014—2015年度,以多蜡质和少蜡质的4个小麦近等基因系为材料,采用田间旱棚方式控制土壤水分,研究了蜡质含量与小麦抗旱性的关系。结果表明,干旱处理后,多蜡质小麦品系旗叶的蜡质含量平均为15.15 mg g^(-1),较少蜡质小麦品系(8.43 mg g^(-1))高79.8%;多蜡质小麦品系旗叶的水势较高,干旱处理后下降幅度明显小于少蜡质小麦品系,水分散失率也显著低于少蜡质品系(P<0.05);多蜡质小麦品系旗叶的光合速率平均下降7.5%,而少蜡质小麦品系下降9.8%;多蜡质小麦品系旗叶PSII最大光化学效率(Fv/Fm)平均下降幅度为3.4%,少蜡质小麦品系下降幅度达到5.8%;多蜡质小麦品系的籽粒产量高于少蜡质品系,平均高3.7%;多蜡质小麦品系的抗旱指数和干旱敏感指数均显著低于少蜡质小麦品系(P<0.05)。以上结果表明,蜡质能够提高小麦的抗旱性,旗叶蜡质含量可以作为抗旱小麦品种的选择指标。

The relationship of flag leaf cuticular wax content with leaf water potential, excised-leaf water loss, leaf photosynthesis characteristics and wheat yield under drought stress were analyzed in 2013–2014 and 2014–2015 wheat seasons using four wheat nearly isogenetic lines（NILs） differing in cuticular wax content in flag leaf. Under drought stress condition, the average flag leaf cuticular wax content of the high-wax NILs（15.15 mg g^（-1）） was 79.8% higher than that of the low-wax NILs（8.43 mg g^（-1））. Compared with the low-wax NILs, the high-wax NILs showed significantly higher water potential in flag leaf and lower water loss rate（P 0.05）. In response to drought stress, photosynthetic rate（Pn） and Fv/Fm of flag leaf declined in both types of NILs, however, the decrease percentages were lower in the high-wax NILs（7.5% and 3.4%, respectively） than in the low-wax NILs（9.8% and 5.8%, respectively）. As a result, the average yield of the high-wax NILs was 3.7% higher than that of the low-wax NILs, and the drought tolerance（TOL） and stress susceptible index（SSI） of the high-wax NILs were significantly less than those of the low-wax NILs（P 0.05）. These results indicate that cuticular wax content in flag leaf is closely related to drought tolerance and can be used as a physiological indicator of drought resistance in wheat selection.