| In this paper the pollen morphology and viability of lotus have been studied systematically.The purposes of the study are to establish a set of quantitive criteria of pollen morphology for lotus and check for the relationship between pollen morphology and variety evolvement ,classification,the relationship between pollen morphological characteristics and plant shape,flower shape,and flower color ;and on the other hand in order to look for the best conditions of pollen storage,suitable culture mediμm for pollen germination and the effects of time of pollen storage on pollen viability,which are the important data for lotus breeding and germ plasm resource research.1. There are a lot of general characters among pollens from 20 varieties of lotus studied.For example, all pollen approaches subglobose, has three germinal furrows along the direction of polar axis,both ends of the germinal furrow are narrow,but it is broad in the middle,there covers compactness kernels in the furrow,and the shape in equator view is oval.These same characters support in the homogeneity of Nelμmbo nucifera in the traditional classification.2. There are significant differences among pollens from 20 varieties of lotus studied.They mainly show the following aspects:①The discrepancy of the microspore size among each variety is great.The largest in size is variety of'Fenqianye',with 51.6×55.8μm,the smallest is'Jinfengzhanchi'with size of 41.7×42.3μm.The size of other pollens fall in between them.②For germinater shape ,there are also a lot of different characters.For example,all the varieties have different width and length of germinal furrow;In the germinal furrow there are several shapes,such as obviously heave,not obviously heave and invaginate.③There are three shapes in polar view,3-labed-rounded,obtuse triangle and subrotundity.④There are significant differences in exine ornamentation,these differences indicate lotus have the rich heredity multiplicity.In unifies other characteristics in the situation,these microscopic shapes differences have the certain systematic significance to varieties division.Using these heredity multiplicities may cultivate the new lotus varieties,though breeding technology,crossbreeding,tissue culture,heredity transformation and so on..3. According to the differences of the exine ornamentation of lotus pollen grains the 20 varieties were divided into 4 groups:①exine cerebroid.The strips are thick and the size of reticulations shape is not regular.The germinal furrow is not straight and the jaw opening is obviously wide.These varieties belong to this type.'Bayi Lian','Baichuantai','Taibai Lian','Dahongpao','Fen Wanlian','Hong Wanlian','Jinfengzhanchi','Fei Tao','Zhong-ri Youyi Lian','Dasajin','Danyantuozhu','Duli','Fenqianye','Gudai Lian','Jiande Honglian','Jifei Lian','Ziyu Lian'.②exine rugulate.The cover has no reticulation.'Taikong Lian'belong to this type.③exine cerebroid-rugulate.The reticulation is extremely small.'Xinhuanufang','Taizhenchuyu'belong to this type.4. The results of Main Component Analysis showed that the importance ranking of the criteria is following:equatorial axis length,volμme index,polar axis length,P/E value, shapes in polar view,germinater character,distance of lirae,style of exine ornamentation,L/P value,fossa length and fossa width.The general important characteristics are pollen size, shapes in polar view, germinater character and style of exine ornamentation.5. 20 varieties were divided into six groups according to the results of the Cluster Analysis.The first group includes 5 varieties:'Bayi Lian','Jifei Lian','Zhong-ri Youyi Lian','Ziyu Lian','Dahongpao'.The second group include 4 varieties:'Hong Wanlian','Danyantuozhu','Jiande Honglian','Gudai Lian'.The third group includes 3 varieties:'Taikong Lian','Dasajin','Fenqianye'.The fourth group includes 3 varieties:'Baichuantai','Taibai Lian','Fen Wanlian'.The fifth group includes 2 varieties:'Jinfengzhanchi','Duli'.The sixth group includes 3 varieties'Fei Tao','Xinhuanufang','Taizhenchuyu'.6. The suitable culture mediμm is 10%cane sugar+100mg/Lboric acid+0.5%agar.7. There is a significant difference in viability of Nelμmbo nucifera pollen among all the varieties.The result of two staining method is higher than the culture method.The methylene blue test obviously can not be as the viability test method of Nelμmbo nucifera pollen.The result of culture method which is more intuitionistic,precise and reliable than staining method can explain the real germination rate of pollen.So it can be the first choice of testing pollen viability.8. The suitable condition for Nelμmbo nucifera pollen storage is 4℃storage.
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