Changes of photosynthetic efficiency and chloroplast ultrastructure of narcissus leaf blades in different development stages

At four development stages of narcissus,i.e.narcissus-bolting stage,flowering stage,blossom fall stage and post floral stage,some physiological and biochemical characteristics of leaf blades,such as photosynthetic rate,transpiration rate,contents of chlorophyll and protein were measured and the change course of the chloroplast ultrastructure was observed.With the development of narcissus,the water content and stomata conductance decrease significantly,the net photosynthetic rate,the respiratory rate and the ratio of photosynthetic rate to respiratory rate also decrease obviously,whereas the content of chlorophyll rises obviously,the value of chlorophyll a/b reduces tardily and the content of soluble protein presents a decreased tendency.Furthermore,the electron microscope observation shows that the ultrastructures of chloroplast grana and grana lamella are developed and clear at bolting stage,inflated and loose at flowering stage,withered at blossom fall stage and disaggregated at post floral stage.