不同灌水量对滴灌水稻叶片光合特性及根系内源激素的影响

Effects of different irrigation amounts on the photosynthetic characteristics of rice leaves and root endogenous hormones under mulching drip irrigation

为探明覆膜滴灌条件下优化水分管理对水稻光合特性及根系内源激素的影响,以‘T-43’(抗旱性)和‘新稻1号’(干旱敏感性)为试验材料,生育期内设8670(W_(1))、10200(W_(2))和12000 m^(3)/hm^(2)(W_(3))3个灌水量处理,测定抽穗期和抽穗后20 d水稻叶片生长、光合荧光特性、根系内源激素、水分利用效率(WUEy)及籽粒产量等指标。结果表明,与W_(3)处理相比,W_(1)条件下2个水稻品种的比叶重(SLW)、叶面积指数(LAI)、气孔导度(Gs)、蒸腾速率(T_(r))及净光合速率(P_(n))均显著下降,根系脱落酸(ABA)含量均显著增加(P<0.05);W_(2)条件下‘T-43’在抽穗期SLW和ABA含量较W_(3)增加10%和90%,但高效叶面积率、叶绿素a和b含量、P_(n)、T_(r)、非光化学淬灭系数(qN)及抽穗后20 d根系ABA含量与W_(3)无显著差异,最终‘T-43’在W_(2)条件下产量及水分利用效率(WUEy)均显著高于W_(1)(P<0.05),而与W_(3)无显著差异。与‘新稻1号’相比,‘T-43’的P_(n)、最大光化学量子产量(F_(v)/F_(m))及产量均显著增加,T_(r)和qN显著降低。相关性分析表明,产量与不同土层根系中ABA、P_(n)、Gs呈显著或极显著负相关,与0—40 cm内水稻根系玉米素核苷(ZR)、P_(n)、Gs呈显著或极显著正相关。不同土层根系中ABA与P_(n)、Gs呈显著或极显著负相关。因此,在覆膜条件下,10200 m^(3)/hm^(2)的灌水量(W_(2))可使抗旱性品种‘T-43’根系中ABA的含量升高,抑制气孔张开、减少地上部蒸腾耗水,同时叶片中叶绿素的降解得到缓解,可维持较高的有效叶面积、保持较强的光合活性,是实现新疆干旱稻作区节水高产目标的有效途径。

To clarify the effects of optimizing water management under the condition of drip irrigation with plastic film mulch on the photosynthetic characteristics of rice leaves and root endogenous hormones,one drought-resistant rice variety‘T-43’and one drought-sensitive variety‘Xindao 1’were used as material.Three irrigation treatments,8670 m^(3)/hm^(2)(W_(1)),10200 m^(3)/hm^(2)(W_(2))and 12000 m^(3)/hm^(2)(W_(3)),were set up during rice growth period.The leaves growth,gas exchange and chlorophyll fluorescence parameters of leaves,endogenous hormones,WUEy and yield at heading stage and 20 d after heading of rice were measured.The results showed that:Compared with W_(3),the specific leaf weight(SLW),leaf area index(LAI),stomatal conductance(Gs),transpiration rate(T_(r))and photosynthetic rate(P_(n))of W_(1)all significantly decreased in both varieties(P<0.05).The abscisic acid(ABA)in root significantly increased.Compared with W_(3),the contents of SLW and ABA in‘T-43’significantly increased by 10% and 90% at heading stage under W_(2)(P<0.05),respectively,but there was no significant difference in high effective leaf area ratio,chlorophyll a content(Chl a),chlorophyll b content(Chl b),P_(n),T_(r),non-photochemical quenching(qN)at heading stages,and the ABA content at 20 d after heading and W_(3)(P<0.05).The yield and WUEy of‘T-43’under W_(2)treatment were significantly higher than those of W_(1)treatment,but had no significant difference with those of W_(3)treatment.Compared with‘Xindao 1’,the P_(n),maximal photochemical efficiency(F_(v)/F_(m))and yield of‘T-43’were significantly increased,but the T_(r)and qN were significantly decreased(P<0.05).The correlation analysis showed that yield was significantly negatively correlated with the ABA,P_(n)and Gs(P<0.05),and was significantly positively correlated with the 0-40 cm soil layer zeatin nucleoside contents,P_(n)and Gs(P<0.05).ABA was significantly negatively correlated with the P_(n)and Gs(P<0.05).Therefore,under 10200 m^(3)/hm^(2) drip irrigation with plastic film mulch,the drought-resistant rice variety could increase the ABA content in roots,reduce stomatal opening and the transpiration water consumption,and mitigate the degradation of chlorophyll,which could maintain higher leaf photosynthetic area and stronger photosynthetic activity.It was an effective way to achieve the goal of water saving and high yield of rice production under drip irrigation in Xinjiang.