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为深入了解玉米在关键发育期干旱条件下的耗水特征及致灾机理,对春玉米‘丹玉39’分别从拔节(T_1)和抽雄(T_2)期开始采用持续无补水方式进行干旱及复水试验,基于对叶和根水势、主要光合变量(净光合速率P_n、蒸腾速率T_r、气孔导度gs、胞间CO2浓度Ci)以及茎流速率(SF)的动态观测,研究各生理参数对干旱及复水过程的响应特征.结果表明:叶、根水势均与土壤湿度呈对数关系,不同时期干旱使二者都减小,对根水势的影响比叶水势提前,与拔节期相比,抽雄期叶水势的干旱响应偏早,根水势偏晚;叶水势在T_1处理复水后能得到恢复,但不能恢复到正常水平,T_2处理不能恢复;T_1处理的根水势对复水的响应比叶水势更快,且更接近于正常水平.P_n和T_r对T_2处理的响应快于T_1处理;复水后二者对T_1处理的恢复速度快于T_2处理,T_1和T_2处理P_n分别超过和达到正常水平,而T_r分别能和不能达到正常水平;T_r对T_1处理的响应早于P_n,二者对T_2处理的响应一致;各处理gs对干旱的响应与P_n一致;T_1处理的Ci与P_n趋势一致,T_2处理相反.各干旱处理SF比对照减小,在晴天比阴天响应明显,SF对T_2处理的响应比T_1处理敏感,在一定干旱水平后响应敏感性减弱;复水后SF比对照明显增大,T_2处理的增幅小于T_1处理.
In order to understand deeply the water consumption characteristics and disaster mechanism of maize under the drought conditions of key developmental stages, spring maize ’Dan 39’ was treated with continuous non-replenishment method Water experiments were conducted to study the effects of various physiological parameters on the dynamic changes of leaf water potential, main photosynthetic variables (net photosynthetic rate P_n, transpiration rate T_r, stomatal conductance gs, intercellular CO2 concentration Ci) and stem flow rate (SF) Drought and rehydration process.The results showed that leaf water and root water potential all had a logarithmic relationship with soil moisture, and the drought at different periods reduced both of them, which had an effect on root water potential earlier than that at leaf jointing stage , The response to leaf water potential at tasseling stage was earlier and the root water potential was late. The leaf water potential could be restored after rehydration at T_1, but could not recover to normal level, and T_2 treatment could not recover. The response of root water potential to rehydration P_n and T_r responded faster to T_2 than T_1, and recovered faster than T_2 and T_1 and T_2, respectively, after rehydration Reach the normal level, but T_r respectively can The response of T_r to T_1 was earlier than that of P_n, and the response of T_r to T_2 was the same as that of P_2. The response of gs to drought was consistent with that of P_n in each treatment; the trend of Ci and P_n was the same in T_1 and opposite in T_2. The response of SF to T_2 treatment was more sensitive than that of T_1 treatment, and its response sensitivity was weakened after a certain drought level. After rewatering, SF was significantly increased compared with that of control, and the increase of T_2 treatment Less than T_1 treatment.