Study On Morphological,Anatomical Structure And Histochemistry Of Plantago Fengdouensis

Plantago fengdouensis is an endangered amphibian species endemic to the Three Gorges Reservoir area in China.It is now a national secondary protected wild plant.It is only distributed in Zhongxian,Fengdu and Banan districts of Chongqing in the Three Gorges Reservoir area of the Yangtze River in China.However,due to the construction of the Three Gorges Project,its wild habitats no longer exist.At present,there is no research on the morphological,anatomical and histochemical characteristics of plantago fengdouensis.In this paper,the morphological characteristics of the roots and leaves of plantago fengdouensis were studied by means of measurement,and the anatomical structure of the roots,stems and leaves of plantago fengdouensis was observed by manual sectioning.The histochemical characteristics were studied by staining.The results can explain the ecological adaptability of plantago fengdouensis.It provides a theoretical basis for the habitat restoration and protection of plantago fengdouensis.The results also provide a theoretical reference for the classification,evolution and phylogenetic study of amphibians.The research results are as follows :(1)Plantago fengdouensis morphological characteristics :The overall morphological characteristics of Plantago fengdouensis in the terrestrial environment were as follows.After 90 days,the root length increased by 38.89 %,the root surface area increased by 109.13 %,the root volume increased by 101.75 %,the average diameter of the root increased by 23.11 %,the number of root tips increased by56.16 %,the number of leaves increased by 37.5 %,the leaf length increased by 82.66 %,the leaf width increased by 2.67 %,the leaf area increased by 87.54 %,the petiole length increased by 101.26 %,the shoot mass increased by 11.68 %,and the root mass increased by 9.74 %.Plantago fengdouensis in terrestrial environment entered the growth peak in March,and then the growth rate slowed down.The root length of Plantago fengdouensis increased by 6.48 % within 30 days and decreased by 28.75 % after 30 days.The root surface area increased by 91.66 % within30 days and decreased by 62.74 % after 30 days.The root volume increased by 68.34 %within 30 days and decreased by 46.09 % after 30 days.The average root diameter increased by 10.47 % within 30 days and decreased by 6.21 % after 30 days.The number of root tips increased by 41.85 % within 30 days and decreased by 89.51 % after 30 days.The number of leaves decreased after 30 days and completely disappeared after 90 days.The leaf length increased by 14.13 % within 30 days and decreased by 81.73 % after 30 days.Leaf width decreased by 57.46 % after 90 days.The leaf area increased by 14.13 %within 30 days and decreased by 92.22 % after 30 days.The petiole length decreased by84.06 % after 90 days.The aboveground weight increased by 6.05 % within 30 days and decreased by 94.74 % after 30 days.The root mass increased by 2.35 % within 30 days and decreased by 29.37 % after 30 days.Plantago fengdouensis in aquatic environment entered the growth peak in March,and then the growth rate slowed down.In summary,the root morphology,leaf morphology,aboveground mass and root mass of Plantago fengdouensis increased first and then decreased in the flooded environment.After 30 days,the leaves gradually decreased and finally disappeared,and the number of roots decreased significantly.(2)Anatomical and histochemical characteristics of Plantago fengdouensis:Plantago fengdouensis has similar microstructure characteristics in both flooding and terrestrial environments.The anatomical structure of adventitious roots of Plantago fengdouensis.Adventitious roots have primary structure and secondary structure.The primary structure of adventitious roots has epidermis,subdermis,exodermis,cortex,endodermis,stele,primary xylem.The secondary structure has exodermis,cortex,channel cells,endodermis,cork layer,secondary xylem,primary xylem,and exodermis cells with casparian strip and suberization.Anatomical structure of stems and pedicels of Plantago fengdouensis.The stem has primary structure and secondary structure.The primary structure includes : cuticle,epidermis,cortex,phloem fiber,outer cortex,inner cortex,primary xylem,pith.Secondary growth occurs in mature stems,and cortical cells divide again to form a cork layer.The pedicel structure includes cuticle,epidermis,endodermis,vascular bundle and aerenchyma.Anatomical structure of petioles and leaves of Plantago fengdouensis.The anatomical structure of petiole includes cuticle,epidermis,endodermis,cork layer,vascular bundle and aerenchyma.The anatomical structure of leaves includes cuticle,upper epidermis,stomata,aerenchyma,lower cortex and cuticle.It is an isobilateral leaf and does not differentiate palisade tissue and spongy tissue.These structures indicate that Plantago fengdouensis is adapted to the terrestrial environment.The apoplastic barrier structure of Plantago fengdouensis.Adventitious roots have kjeldahl bands and suberized inner and outer cortex,which are composed of suberized cork layer in the late stage;mature stems are composed of cork layer;pedicel,petiole and leaf are composed of cuticle,endodermis and lignified annular sclerenchyma.The inner cortex and outer cortex of the root have short-term dividing cells.Aerenchyma structure of Plantago fengdouensis.There are intercellular spaces in the roots,and the pedicels and petioles have fissured air cavities.The phloem has a large irregular air cavity,and the vascular bundle cells in the stem are partially dissolved into a small amount of aerenchyma.In summary,the apoplastic barrier structure and aerenchyma in the roots,stems and leaves of Plantago fengdouensis enable it to adapt to the amphibious environment of the Three Gorges riparian zone in China.This adaptive feature can help explain why the plant can grow in the flooded Yangtze River fluctuation zone environment.