Study on Morphology and Anatomy during Seed Development of the Endangered Plant Michelia wilsonii
[Objective]This study aims to explore the morphological and anatomical characteristics dur-ing seed development of Michelia wilsonii,analyze the biological mechanism of seed reproduction and the reasons for their endangerment,and provide theoretical basis for the ecological conservation of endan-gered plants.[Method]The seeds of M.wilsonii at different developmental stages were used as experi-mental materials,the morphological and anatomical characteristics were observed by paraffin section under microscope,and the nutrient content was measured by plant physiological methods.[Result]At the initial stage of development,the seeds exhibited a yellow-green hue and a spherosome shape,eventually matur-ing into a round-bullet shaped.The epidermis was characterized by a red,and leathery texture and con-sisted of 3-4 layers of epidermal cells.The mesotesta displayed an orange-red and fleshy appearance,composed of parenchyma tissue,contained abundant ergastic substance,with a pronounced oily texture.The flat cells within the endothelium differentiated into sclerenchymatous cells,which gradually became hard and woody,undergoing a color transition from white to black.The endosperm was composed of paren-chymal cells,containing a higher concentration of colored ergastic substance inside the cells.Its morphol-ogy gradually developed from transparent liquid state to solid solidified state.The development of the seed embryo proceeded through four stages:spherical,heart-shaped,torpedo shaped,and cotyledon shaped.By the time of the seed dispersed,the cotyledon-shaped embryo was fully developed.The soluble sugar content initially increased during seed development but subsequently decreased.The con-tents of starch and soluble protein exhibited a gradual increase during the initial stages of seed develop-ment,and gradually stabilized in the middle and later stages.The crude fat content increased rapidly in the early stage,followed by a deceleration in the later stages.[Conclusion]During the process of seed development,several issues were identified,including colorful epidermis,high fat mesotesta,poor per-meable endothelium,early cessation of seed growth,abnormal endosperm development in middle and later stages,and low embryo content,which lead to the inferior seed quality of M.wilsonii,impede the natural germination and regeneration process,and is one of the important reasons for population decline and even endangerment.
seed developmentmorphology and anatomynutrientsMichelia wilsonii
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