不同施肥水平对水稻生育进程中功能叶光合性能及水势变化的影响

采用盆栽试验法测定了3种施肥水平对嘉育948和G7两个籼稻品种(系)从拔节期到成熟期叶片水势及其组分和叶色值、叶绿素荧光参数Fv/Fm与Fv/Fo及光合速率等光合生理特性变化的影响,结果表明:两品种的叶色值和叶绿素荧光参数在抽穗后总体呈下降趋势,但提高肥力水平可延缓其下降速度;嘉育948在高肥条件下后期光合速率下降减缓,而G7在中肥条件下可维持其光合速率在整个生育进程处较高水平。两品种(系)叶片水势均表现先升后降的相似变化趋势,但提供相应的营养水平可维持其在灌浆期处较高水平。叶片水势及其组分与光合特性的回归分析表明,嘉育948叶片光合生理指标主要受叶片水势的正向调节;G7除光合速率受叶片水势正向调节和渗透势负向调节外,其余光合生理指标则受叶片水势和压力势正向调节,说明叶片水势对光合特性及衰老的影响存在基因型差异。

Effects of Fertilizer Supplies on Photosynthetic Characteristics and Water Potential of Functional Leaf in the Progress of Growth and Development of Rice

Pot trial was conducted to detect changes of water potential,leaf color readings(SPAD),chlorophyll fluorescence kinetics parameters Fv/Fm and Fv/Fo and photosynthetic rate of the largest functional leaves in two Indica rice cultivars,Jiayu 948 and G7,from elongation to ripeness stage under different fertilizer supplies.At the same time,we analyzed the influences of leaf water potential and its constituents on leaf senescence using the photosynthetic physiological characteristics as indictors.The results showed that,SPAD,Fv/Fm and Fv/Fo of both cultivars reached their own maximal values during heading stage and then decreased generally,but when higher fertilizer was supplied,decreasing rate of the said physiological characteristics slowed down.The photosynthetic rate of Jiayu 948 declined slower under higher fertilizer supply from elongation stage,while,that of G7 maintained higher level under the middle fertilizer supply.Leaf water potential of both cultivars showed similar change,i.e.increased at first and declined then,but when suitable level of fertilizers was supplied according to the nutrition requirement of cultivar,higher level of water potential could be maintained from heading to milk ripe stage.The results of multiple regression analysis revealed that,leaf water potential and its constituents was closely related to the photosynthetic characteristics in both cultivars.In Jiayu 948,SPAD was regulated by water potential and osmotic potential positively,the other photosynthetic characteristics by water potential positively only.In G7,photosynthetic rate was regulated by water potential positively but by osmotic potential negatively,the others by both water potential and pressure potential positively.It was concluded that,the influences of leaf water potential on photosynthetic characteristics and leaf senescence were significantly different due to various genotypes.