| Eurya belonging to Theaceae, mostly evergreen shrubs or small trees and flowering in winter, is a very important nectar plants and potential garden plants. The genus Eurya Thunb.was described as strict dioecy in most of the literatures, and gender variation was rarely occured. Gender variation was found in Eurya obtusifolia H. T. Chang during field investigation. It has special and important significance for exploring the sex differentiation and evolution of plants. But, so far, the research about Eurya have focused on classical taxonomy and nectar plant resources investigation, while few studies paid attention about its gender differentiation.The differences of physiological indexes in leaves were closely related to the sex of plants. In this study, we use leaves of female, male and hermaphrodite plants of E. obtusifoliaas as materials to study the physiological and biochemical changes in critical flower growth stages. The physiological and biochemical indexes were determined and analyzed to explore its role in E. obtusifolia sex differentiation, and then provide us basic information for further research about the law of sex differentiation and the reason of sex variation phenomenon. The main results are as follows:1 、 The contents of endogenous hormone(IAA, GA3, ZR and ABA) were determined by HPLC, then hormone proportion and hormone dynamics were analyzed.The results showed that: endogenous hormone had a certain variation, and there were significant differences among different sexes E. obtusifolia during flowering stages. From a single hormone point of view: the content of IAA increased at first and then decreased in female and hermaphrodite plants at all measured stages, while the male plants were relatively low and stable; the content of GA3 was highest in the vegetative growth stage, however, it decreased sharply after entering the reproductive stage, while the content of GA3 in male and hermaphrodite plants increased gradually and higher than that of female; the content of ZR in male and hermaphrodite plants increased first and then decreased, and it was higher than that of female plants all the time, while the ZR content in female plants was stable; the content of ABA in female, male and hermaphrodite plants was insignificant, and the variation was also similar.From the hormone balance point of view: the ratios of ABA/ZRand GA3/ZR in female plants were significantly higher than male and hermaphrodite plants in most stages, and the trends of male and female were similar; the ratios of IAA/ZR increased firstly. and then decreasedin female and hermaphrodite plants, and it was low and stable in male plants, while the ratio of IAA/ZRin hermaphrodite plantswas between the male and female plants; the ratios of ABA/IAA and GA3/IAA decreased first and then increased, and they gradually increased in male plants and were significantly higher than female and hermaphrodite plants, while the trend of ratio of ABA/IAA in hermaphrodite plants was similar to female plants and the ratio of GA3/IAA was similar to male plants. The results showed that, the increase of GA3 and ZR contents was beneficial to the development of stamens. High level of IAA contents promoted the development of female flowers. ABA had negligible effect on sexual differentiation. High ABA/ZR, IAA/ZR, GA3/ZR ratios could promote the development of female flowers, while high ABA/IAA and GA3/IAA ratios were beneficial to male flowers development.The research about the changes of soluble protein,Soluble sugar, MDA and antioxidant enzymes(SOD、POD) in the leaves among different sexes of E.obtusifolia during flowering stages showed that:1) The contents of soluble protein in male, female and hermaphrodite plants were increased firstly and then decreased, and tended to be stable, they all reached the peak at squaring stage, and the female and hermaphrodite plants were significantly higher than male. The accumulation of soluble proteins was beneficial to the differentiation of flower bud, and higher content of soluble protein could promote the development of female and hermaphrodite flower.2) The contents of soluble sugar in male, female and hermaphrodite plants showed a curve of “up-down-up”. The soluble sugar wasrelatively low in vegetative growth among different sexes of E. obtusifolia, then increased rapidly and reached a peak of male plants, and also reached the first peak of female and hermaphrodite plants, the hermaphrodite plants were significantly higher than that of the female, and the female was significantly higher than that of the male at this stage. The accumulation of soluble proteins was beneficial to the differentiation of flower, and higher content of soluble protein could promote the development of pistil. It showed that the accumulation of soluble sugar was beneficial to the differentiation of flower bud, and higher content of soluble sugar could promote the development of female and hermaphrodite flower.3) The contents of MDA in male, female and hermaphrodite plants were increased firstly and then decreased. The MDA wasrelatively low in vegetative growth among different sexes of E. obtusifolia, then increased until male and female full bloom stage, and then continued to decrease. The content in female plants was higher than that of the hermaphrodite, and the hermaphrodite was higher than that of the male at most determination stages. We can infer that the changes of MDA had some impact on the sex differentiationof E. obtusifolia.4) The activity of SOD in male, female and hermaphrodite plants were increased rapidly and then tended to be stable. The activity of SOD wasrelatively weak in vegetative growth among different sexes of E. obtusifolia, then increased and maintained a high activity. The activity of SOD in male and hermaphrodite plants was higher than that of the female, and there was no significant difference between male and female. We could infer that the higher activity of SOD was beneficial to the differentiation and development of stamens.5) The activity of POD in male, female and hermaphrodite plants were increased rapidly and then decreased sharply, and increased gradually at florescence end. The activity of POD wasrelatively weak in vegetative growth among different sexes of E. obtusifolia, then increased and all reached the peak at squaring stage, and then decreased sharply at the stage of bud swelling and came out white petals, then increased again at the stage of florescence end. The activity of POD in hermaphrodite plants was higher than that of the male, and the male was higher than that of the female at all stages. We could infer that the higher activity of POD could promote the development of male and hermaphrodite flower.From the above results, endogenous hormone and other physiological indexes had some regular changes during flowering stages, and there were certain differences among different sexes E. obtusifolia. It showed that these physiological indexes were closely related to the sex differentiation of E. obtusifolia. |
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