Studies on the occurrence of monoecious variants during vegetative propagation of spinach and asparagus plants by tissue culture techniques

植物性别表达的变化发生在组织培养的微繁过程中。为了阐明这一机制，本研究通过实验寻找性别表达由雄性或雌性转化为雌雄同株的变异株，并分析其生长习性、形态特征和坐果频率。此外，通过组织培养进行微繁殖，追求性别表达的实际变化。此外，还介绍了芦笋和菠菜花中蛋白质的分析方法。在实验农场中，我们鉴定了几种具有花药和坐果力的芦笋植株。芦笋的未成熟花通常表现出雌雄同体的形态，在成熟的过程中，通过子房组织和胚珠的阶段特异性阻滞形成完整的雄花。然而，与MW 500W的雄花相比，能够坐果的雄花子房较大，花柱较长，柱头正常。子房内的一些胚珠似乎是活的。芦笋植株的花在子房形态和花柱长度上表现出一定程度的差异。以菠菜愈伤组织为再生体，在体外长时间光期培养至开花。根据花的形态来鉴定供体植株和再生植株的性别。从雌性植株的根段获得的植株都是雌性的，而从雄性植株获得的植株包括在同一株植株上有雌花和雄花的单子花。这些结果表明，芦笋和菠菜的性别表达表现为一种灵活的表型，通过组织培养过程从雌雄异株向单株融合，并且雄性植株比雌性植株更容易发生性别转换。

It has been known that the variation of sex expression in plants occurs during micropropagation through tissue cultures. In order to elucidate the underlying mechanism, the experiments was conducted to find variants that the sex expression had been converted from male or female to monoecious plants and analyze their growth habits, morphological features and the frequency of fruit setting. Moreover, the actual changes in sex expression were pursued by carrying out micropropagation through tissue cultures. In addition, the methods for analysing proteins extracted from asparagus and spinach flowers.In the experimental farm we identified several asparagus plants having anthers and carrying potency to set fruits. Usually immature flowers of asparagus show hermaphroditic morphology, forming complete male flowers by stage-specific arrest of ovary tissue and ovules on the way to maturation. Nevertheless, flowers on male asparagus plants which were able to set fruits had large ovaries and a long style with normal stigma, compared with those of MW 500W male flowers. Some ovules within the ovaries seemed to be alive. The flowers on the asparagus plants showed an extent of variation in the morphology of ovary and the length of styles. Spinach plants regenerated from root calli were grown in vitro under long photoperiod until flowering. The gender of donor plants and regenerants were identified based on the morphology of flowers. The plants derived from root segments of female plants were all female, while those from male donors included monoecy which bears female and male flowers on the same plants.These results suggest that the sex expression of asparagus and spinach is manifested as a flexible phenotype, converged from dioecy to monoecy by the tissue culture procedure and that male plants was susceptible to sex conversion than female plants.