The objective of this study was to define further characters of water consumption and physiological responses at different soil humidity in naked oat. Pot experiment Ⅰ was conducted to investigate transpiration coefficient among naked oat, maize, sorghum, barley and spring wheat, and supplied water by a hydraulic pressure-controlled auto irrigator. In pot experiment Ⅱ, three heights of pressure-adjusting pipe (i.e. 40, 60 and 80 cm) were used to make three levels of soil humidity (high humidity-moderate humidity-low humidity) to evaluate light responses and antioxidant enzyme activities of leaves at booting stage in naked oat. The results showed that the transpiration coefficient of naked oat was 455.37, significantly (.P<0.05) higher than other's crops. Lower soil humidity decreased SPAD, however, leaf photosynthetic ability was not significantly (P>0.05) restrained when appropriate to reduce soil humidity. Improving leaf water use efficiency was improved when appropriately increasing the degree of stomatal limitation. Leaf antioxidant enzyme activities showed different responses to three levels of soil humidity. SOD was significantly induced in moderate humidity, but POD and CAT were improved in high and low humidity, respectively. The results suggested that naked oat was a kind of crop required more water and low water use efficiency with higher stomatal conductance and lower net photosynthetic rate and leaf photosynthesis and antioxidant enzyme activities were not significantly decreased when reducing appropriately soil humidity.%为进一步明确裸燕麦耗水量及其在不同土壤水分状况下的生理反应,论文在盆栽试验条件下,以负水头持续供水系统为供水装置,比较了裸燕麦、玉米、高梁、大麦和小麦旱地禾本科作物的水分耗散；设置40、60和80 cm 3个负水头控压高度,测定了“高-中-低”3种土壤湿度下裸燕麦孕穗期叶片光响应曲线及叶片保护酶活力.结果显示:裸燕麦蒸腾系数为455.37,显著(P＜0.05)高于其他作物,较高叶片蒸腾速率和较低净光合速率是主要生理原因；降低土壤含水量将降低裸燕麦叶片相对叶绿素含量,但适度降低土壤含水量并未显著(P＞0.05)降低叶片光合能力,而适度提高气孔受限程度,有利于提高叶片水分利用效率:超氧化物歧化酶( SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)等叶片保护酶活性对不同土壤水分状况响应不一致,中等土壤湿度时SOD活性较高,高土壤湿度时POD活性较高,低土壤湿度时CAT活性响应程度较高.
展开▼
