水分胁迫对覆膜滴灌棉花根系活力和叶片生理的影响

采用田间试验法，分析不同程度水分胁迫条件下棉花花铃期根尖根系活力、叶片叶绿素、脯氨酸和丙二醛含量变化，并对叶片脯氨酸、丙二醛含量和根系活力与土壤含水率进行相关性分析。试验以60 cm土层田间持水量的105%、100%、95%、90%、85%、80%为灌溉上限，共设6个灌水梯度，即5 400、4 950、4 500、3 750、2 850 m³/hm²和2 550 m³/hm²。结果表明：单株叶片干重及叶面积、地上部干生物量、株高、叶绿素含量随灌水量的减少而降低，根冠比随灌水量的减少而增加。脯氨酸及丙二醛含量随灌水量的降低而升高，且与土壤含水率呈负相关关系，相关系数（r）分别为-0.704和-0.667；根系活力随灌水量的降低而降低，与土壤含水率呈正相关关系，其相关系数为0.67。当灌水上限为95%，即灌水量为4 500 m³/hm²时，作物表现出轻微的水分胁迫，随灌溉量的继续降低，胁迫加重。植物体内脯氨酸、丙二醛含量及根系活力与土壤含水率的相关关系在一定程度上可以用来表征棉花受干旱程度，可为棉花的灌溉管理提供参考依据。

Effect of Water Stress on Root Vigor and Leaf Physiology of Cotton under Mulch Drip Irrigation

Water stress is one of the most important abiotic stresses.A field experiment was conducted to evaluate the growth and physiological response of cotton plants to soil moisture stress under mulch drip irrigation.The total irrigation volumes of 5 400,4 950,4 500,3 750,2 850 and 2 550 m3/hm2 were designed for each treatment according to the upper irrigation limits of 105%,100%,95%,90%,85% and 80% of field capacity,respectively.Differences in root vigor,chlorophyll,proline and malondialdehyde(MDA) contents were tested at cotton florescence and boll stage so as to reveal the physiological response of cotton plants to soil moisture stress.The relationships between soil moisture content and the praline and MDA contents as well as root vigor were analyzed.The results showed that the biomasses of dry shoots and leaves,leaf area,plant height,chlorophyll content and root vigor were significantly decreased due to water deficiency,while the root-shoot ratio,proline and MDA contents were sharply increased.The results also revealed that there was a negative correlation between soil moisture content and the proline and MDA contents,their correlation coefficients were-0.704 and-0.667 respectively,but the root vigor was decreased with the decrease of irrigation volume,their correlation was positive,and their correlation coefficient was 0.67.Moreover,this study revealed that the threshold level for water supply was 4 500 m3/hm2 to keep crop away from water stress.These results also revealed that the proline content,root vigor and MDA content were sensitive to soil moisture content.