水分胁迫和氮肥对花生根系形态发育及叶片生理活性的影响

Effects of water stress and nitrogen fertilization on peanut root morphological development and leaf physiological activities

以＂花育22号＂花生为试验材料,在中度干旱胁迫和充足灌水两个水分条件下,分别设置不施氮肥（N0）、中氮（N1,90 kg·hm-2）、高氮（N2,180 kg·hm-2）3个施氮水平,研究不同土壤水分和氮肥条件对花生叶片生理活性及根系形态发育特征的影响.结果表明：与不施氮肥处理相比,两个水分条件下中氮处理均显著增加花生产量,但对收获指数无显著影响.干旱胁迫条件下,中氮处理对总根系生物量和总根长无显著影响,但显著增加花生总根系表面积;中氮和高氮处理均显著增加20~40 cm土层内根长和根系表面积,且高氮处理显著增加40 cm以下土层内根系生物量和根系表面积;施用氮肥显著提高叶片过氧化氢酶（CAT）和过氧化物酶（POD）活性,而丙二醛（MDA）含量随施氮量的增加而降低.正常供水条件下,施用氮肥显著降低了花生根系表面积和40 cm以下土层内根系生物量、根长和根系表面积,中氮处理可提高叶片保护酶活性.相关性分析表明,20~40 cm土层内根长和叶片超氧化物歧化酶（SOD）、CAT、POD活性与产量呈显著相关.

Taking ‘Huayu 22＇ peanut as test material, effect of soil water content and nitrogen fer- tilization on the leaf physiological activities and root morphological characteristics of peanut plants were analyzed. Two levels of soil water condition were ： （ 1 ） well-watered condition and （2） moder- ate water stress, and three levels of nitrogen were ： （ 1 ） none nitrogen （ NO） , （2） moderate nitro- gen （N1, 90 kg · hm-2） and （3） high nitrogen （N2, 180 kg· hm-2）. The results showed that N1 significantly increased the peanut yield under two water conditions, but showed no significant effect on harvest index compared with NO. Under water stress condition, N1 had no significant effects on total root biomass and total root length, but the total root surface area was remarkably increased. The nitrogen fertilization significantly increased the root length and root surface area in 20-40 cm soil layer, and N2 significantly increased the root biomass and root surface area in the soil layer below 40 cm. The application of nitrogen remarkably increased CAT and POD activities in leaf, while MDA content was decreased with the increase of nitrogen level. Under well-watered condition, the root bi- omass, root length and root surface area in the soil layer below 40 cm and total root surface area were significantly reduced by nitrogen application, however, only N1 could increase leaf protective enzyme activities. Correlation analysis showed that the root length in 20-40 em soil layer and SOD, CAT, POD activities in leaf were highly significantly related with peanut yield.