| Photosynthesis is an important physiological process that affects crop yield formation and efficient water use.The cotton plant source is multi-kudo,the source-sink correspondence is complex,and the sensitivity of each source pool to water is very different.As a result,cotton has not fully explained the individual water use mechanism from the perspective of single-leaf photosynthesis,and has not developed.Corresponding biological water saving measures.The bell-leaf system is the basic unit of cotton yield formation,and the main stem,leaf and leaf of the bell-leaf system have important contributions to the development of cotton boll despite the complex relationship between them.Therefore,this study adopts the concept of"flower leaf system photosynthesis",and by setting different degrees of water deficit treatment,reveals the relationship between photosynthetic performance of the bell leaf system and the weight of the corresponding system,and analyzes the water deficit to simplify the cotton plant type.The reduction of the number of leaf systems and the adjustment of the spatial distribution of cotton bolls explored the regulation of water deficit on the photosynthesis of various organs in the leaf system,providing a theoretical basis for further optimization of canopy structure.1.Water deficit inhibits the growth of cotton stem diameter and main stem internode length,reduces the number of fruit branches and fruit nodes of cotton plants,reduces plant height,reduces branching ratio,and increases cotton boll shedding rate,simplifying cotton The plant type reduces the number of bell leaf systems and affects the yield of cotton.In the case of water deficit,compared with the fruit branches,the main stem leaves have an important contribution to the establishment of plant morphology and the formation of boll number per plant.It also shows that cotton can adjust the morphological characteristics of plants under adverse conditions,adjust the source-sink relationship of cotton,and ensure the normal maturity of existing cotton bolls.2.Water deficit has a significant regulatory effect on the photosynthesis of the leaf system and the relationship between the leaf source and the bell.Under the condition of increasing water deficit,the leaf-leaf system changed the photosynthetic capacity of the main stem and fruit branches,weakened the photosynthetic function of the fruit branches and leaves,and increased the supply of the main stems and leaves to the photosynthetic products of cotton bolls.Compared with the main stems and leaves,the photosynthetic area of the branches and leaves and the proportion and number of the bell-leaf system gradually decreased with the increase of water deficit,and the single boll weight decreased significantly.The weakening of fruit branches and leaves is the feedback effect of cotton boll development on the leaf system nutrient,and it also reflects that the optimization of photosynthetic function of the bell leaf system is a good regulation function for external stress.3.Water deficit significantly reduced the dry matter accumulation of the cotton bell leaf system.Among them,with the advancement of the fertility process and the increase of water deficit,the dry matter of fruit branches and leaves in the cotton bell leaf system accounted for51%of the dry matter of the system,while the dry matter of the main stems accounted for the increase of the dry matter of the system.For 61%,the dry matter of eucalyptus leaves decreased greatly,and the change of dry matter of stem and bell shell was relatively stable.It provided nutrients for the development of cotton boll in the late stage of cotton development.4.Water deficit increased the water use efficiency(WUEET)of cotton economic yield and the water use efficiency(WUEBW)of aboveground biological yield,which was the highest under mild water deficit conditions.Under normal irrigation and severe water deficit,the WUEET of cotton decreased significantly.Compared with the treatment of mild water deficit,the growth of fruit branches and leaves under normal irrigation was too strong,which promoted fruit segmentation and produced a large number of ineffective cotton bolls.Under the condition of severe water deficit,the growth of fruit branches and leaves was inhibited,the supply of cotton boll nutrients was insufficient,the cotton bolls fell off a lot,and the weight of single bolls decreased.Pay attention to the growth of the leaves and leaves of the bell-leaf system,avoid the loss of excessive water or insufficient supply of nutrients to provide new ideas for improving water use efficiency. |
