| In order to find out whether date plum has apomixis characteristics and know the type of apomixis,the 45 female individuals from date plum nursery of the new east section of Henan Institute of Science and Technology were used to field investigation by bagging,paraffin sectioning and molecular marker technique in this experiment.We were investigated the individual with apomixis ability and surveyed the setting percentage and the morphological characteristics of fruit and seed by different pollination conditions.The developmental processes of ovules and embryo sac and the relationship between this process of ovary and the external morphology of the female flower were explored.Furthermore,the degree of uniformity in at the gene level was studied.The main findings are as follows:(1)According to the investigation,only 14 of the 45 individual plants had apomixis ability,and31.1% of the group had this ability.Among the 14 plants,the apomict rate had significently different.The Apomixis of fruit proportion and number of seeds obtained from 100 bagged fruit of xc-4 are 50% and 175 respectively.It can be treated high apomixis.The Apomixis of fruit proportion of xc-13 and xc-17 are13.5% and 15.7% respectively.These number of seeds obtained from 100 bagged fruit are 69 and 57.This can be divided into moderate level apomixis ability.The number of seeds abtained from 100 bagged fruit of the remaining 11 plants were lower than 50 seeds,this apomixis ability are lower.(2)In order to understand the influence of distant pollen and inactivated pollen on apomixis of dateplum,different pollen were used to stimulate stigma.The apomixis of fruit proportion in the treatment of inactivated dateplum pollen and persimmon pollen are 6.7% and 18.9%.And the number of seeds obtained from 100 bagged fruit are 31 and 70 respectively.However,The apomixis of fruit proportion and the number of seeds obtained from 100 bagged fruit in the treatment of bagging are 31.5% and 126.It can be seen that inactivated pollen and distant pollen cannot improve the dateplum`s apomixis ability.(3)The fruit of apomixis was smaller and weighter than natural pollination.There was a significant difference in fresh weight per fruit.However,the fruit shape index of apomixis is higher than natural pollination.By counting the seed characteristics of different pollination conditions,it can be seen that the apomixis and natural pollination did not show significant differences in fresh weight per seed,but the apomixis had a high seed-shape index.There was no significant difference in the fruit color in bagging treatment and natural pollination.(4)The rates of seed germination under bagging,persimmon pollen,inactived date plum pollen,xx-24 date plum pollen,xx-21 date plum pollen and natural pollination treatments were 93.8%,72.4%,100%,84.6%,80.0%,96.0% respectively.Although the germination rate of offspring with different treatment,the germination uniformity was greatly different.The germination of the progeny of bagging,granted persimmon pollen and granted xx-21 date plum pollen were concentrated in the second week,and the germination was relatively early and neat.The germination potential were 95.3%,61.3%,75.6%respectively.The germination of the progeny of granted xx-24 date plum pollen and natural pollination were concentrated in the third and fourth week respectively.The germination potential were 17.9% and32% respectively.It can be seen that the germination of apomixis progeny is relatively earlier and neater than natural pollination treatment.(5)The annual growth of the six treatment offspring was 17.90-20.69 cm in plant height,3.03-3.73 mm in root diameter,2.35-2.80 mm in stem diameter at 1/2,20.00-22.65 cm in crown width,and16-19 leaves.The standard deviation and coefficient of variation in plant height,crown width and leaf number were lower in the bagging and inactive date plum treatment.It was seen that the individual plant had unanimous growth.There were no significant difference in the standard deviation and coefficient of variation for the root diameter and stem diameter at 1/2 in each treatment.(6)Using the seven pairs of primers to amplify 32 populations,one of them was a female plant and the remaining 31 samples were from seedlings that were progeny of bagging treatment by the female parent.A total of 78 alleles were obtained using this molecular marker technique.Through amplification bands we can find that the amplified fragments were mostly distributed in 100-700 bp.With the amplification of different primers,the test samples has a high uniformity.The uniformity of band was expressed by the mean of the percentage of band.The uniformity of band among the test samples under the DS1,DS3,DS22,DS23,DS31,DS32 and DS49 premers was 94.2%,92.3%,81.6%,82.7%,90.6%,91.3%,91.4% respectively.The genetic similarity coefficient among all individual plant was between0.7215-0.9695 and the genetic distance was between 0.0310-0.3264.It can be seen that the apomixis of the date plum has a high genetic identity at the level of DNA.(7)The apomictic embryo sac development patterns of date plum is pod-shaped embry sac.Its development period is divided into: sporogenous mother cells,megaspore mother cells,dyad stage,tetradstage,mononucleate period,four-nucleus embryo sac and mature embryo sac.It can be speculated that the type of apomixis of date plum may be parthenogenetic or apogamety. |
PDF Full Text Request