不同抗旱性狗牙根地上地下表型特征及内源激素对干旱胁迫的响应

为了研究干旱胁迫对不同抗旱性狗牙根形态建成及内源激素的影响，明确不同抗旱性狗牙根响应干旱的表型特征及内源激素差异，探讨狗牙根表型特征与内源激素的相关性，丰富狗牙根抗旱理论以及生产实践中利用外源激素调控其抗旱性提供参考。采用PVC管栽植狗牙根，控制不同水分达到预设梯度维持10 d，对其叶、根相对含水量、相对电导率、内源激素吲哚乙酸(IAA)、脱落酸(ABA)、赤霉素(GA₃)、玉米素核苷(ZR)、油菜素内酯(Br)]、叶部特征(叶长、叶宽、叶面积)、根部特征(总根长、根表面积、根体积、根平均直径、根干重、最长根长、根系活力)进行测定，分析干旱胁迫下不同抗旱性狗牙根叶、根内源激素比例变化及表型特征与激素的相关性。结果表明，随着干旱胁迫加剧，显著降低了2类狗牙根的叶长、叶宽、叶面积、根平均直径，促进了根部生长发育；提高了叶、根ABA含量，降低了IAA、GA₃、ZR、Br含量，且IAA/ABA、GA₃/IAA与叶部指标、根部指标呈相反相关性，这均从侧面表明狗牙根叶、根在干旱胁迫下选择了相反的生存策略，即促进地下部生长，抑制地上...

Aboveground and belowground phenotypic characteristics of Cynodon dactylon lines differing in drought resistance and endogenous hormone response to drought stress

This study investigated the effects of drought stress on Cynodon dactylon lines varying in drought resistance， in order to identify patterns in morphological and ecophysiological traits and endogenous hormone levels correlated with drought resistance. It was anticipated this research would enhance understanding of drought resistance in C. dactylon and thereby provide a theoretical basis for use of exogenous hormones to regulate drought resistance in industry practice. Plants were established in pots made from PVC pipes then subjected to predetermined levels of water deficit for 10 days. The relative water content， relative conductivity， endogenous hormones ［indole acetic acid （IAA）， abscisic acid （ABA）， gibberellin A₃ （GA₃）， zeatin riboside （ZR）， brassinolide （Br）］， leaf characteristics （leaf length， leaf width， leaf area）， root characteristics （total root length， root surface area， root volume， root average diameter， root dry weight， longest root length and root activity） were measured. The changes in endogenous hormone levels in leaves and roots of C. dactylon with different drought resistance and the correlations between phenotypic characteristics and hormones were analyzed. The results showed that with increased intensity of drought stress， leaf length， leaf width， leaf area and root average diameter of both drought-tolerant and intolerant C. dactylon were reduced， while the growth and development of roots was promoted. The content of ABA in leaves and roots was increased， and the contents of IAA， GA₃， ZR and Br were decreased， and IAA∶ABA and GA₃∶IAA ratios were inversely correlated with leaf indexes and root indexes. This showed that the leaf and root systems of C. dactylon root adopted contrasting survival strategies under drought stress： promotion of underground growth and reduction in aboveground growth. Drought-resistant C. dactylon exhibited comparatively better adaption to a water deficit stress environment by maintaining some growth， larger leaf area， a more developed root system and higher ZR∶ABA， GA₃∶ABA， IAA∶ABA and Br∶ABA ratios under the same level of water deficit stress.