矮生菜豆胚乳细胞形成时的超微结构研究

应用透射电镜对矮生菜豆的游离核胚乳、胚乳细胞及珠被绒毡层的超微结构进行了观察,揭示了胚乳细胞化过程中自由生长壁的形成方式。实验表明,在游离核胚乳中存在大量有被小泡,胚乳游离核的外层核膜发生明显外突并以出芽的方式产生有被小泡。初始胚乳细胞壁为自由生长壁,大量有被小泡融合于自由生长壁末端使之不断延伸并产生分枝。与珠被绒毡层相邻的胚乳细胞产生发达的壁内突,具有传递细胞特征;在这些细胞中出现大量的核糖体及粗糙内质网,表现现高度的合成活性。     

STEM ANATOMY AND INTERNODAL DEVELOPMENT IN PHASEOLUS VULGARIS

Internodal length in Phaseolus vulgaris decreases slightly from one through three, then sharply increases in four, and subsequently decreases toward the apex. Two internodes undergo rapid growth at a given time, although they do not mature concurrently. Early growth of the internode takes place throughout, with later growth limited to successively higher levels. Elongation results from both cell division and cell elongation, and the relative importance of these two phenomena is significant in determining final length. The difference in final length between internodes is brought about by rate rather than period of growth. The procambium is relatively homogeneous in structure, whereas the cambium consists of both fusiform and ray initials. During stem development the vascular meristem gradually acquires the characteristics of the cambium. By the time elongation ceases, the meristem has developed all the characteristics of the cambium.     

THE INTERACTION OF AUXIN AND ETHYLENE IN THE MAINTENANCE OF LEAF BLADE FORM IN PHASEOLUS VULGARIS L. VAR. PINTO

Auxin treatment results in hyponastic curvature of the primary leaves of Phaseolus vulgaris L. var pinto. Ethylene production by hyponastic leaves is detected within 1 hr after treatment with IAA in concentrations at or above 1 μm. The amount of ethylene detected is proportional to the concentration of auxin applied. Untreated control leaves and leaves treated with 2,3,5-tri-iodobenzoic acid or gibberellic acid did not produce ethylene detectable by our equipment. The hyponastic curvature induced by auxin treatment can be inhibited by exogenous application of ethylene or ethylene-generating compounds, and these treatments produce epinasty in auxin-treated leaves. Treatment with inhibitors of ethylene synthesis or action, such as aminoethoxy-vinylglycine, carbon dioxide, or heat treatment, prolong hyponasty. The planar form, therefore, appears to be affected by both hyponastic auxin effect and an epinastic ethylene effect.     

菜豆胚乳游离核中的线粒体(简报)

在植物细胞中,细胞核以及具DNA的细胞器——质体和线粒体,在结构上通常各具自身的被膜而独立存在。关于核与这两种细胞器以及两种细胞器之间通过外膜的连接在一些植物中已有报道。最近,Yu和Russell在烟草中发现了细胞核中存在线粒体的现象。本     

DEMOGRAPHIC ASPECTS OF FLOWER AND FRUIT PRODUCTION IN BEAN PLANTS,PHASEOLUS VULGARIS L.

In this paper we assess the relative contributions to total pod yield of cohorts of flowers of known age. Bean plant (Phaseolus vulgaris L.) growth was monitored and 'births' of individual flowers were recorded and their fates followed. For every cohort of flowers an array of yield measures was calculated, including the mean and total cohort dry weight of fruits, and the numbers of viable and aborted seeds and completely undeveloped ovules. When mature, pods were removed from half of the plants. Plants whose mature pods were removed produced significantly greater numbers of flowers, ovules and viable seeds and a greater total weight of pods than did untreated plants. However, the proportion of ovules giving rise to viable seeds and to aborted seeds and undeveloped ovules was the same in plants of both groups. Approximately 50% of ovules of marketable pods, in all plants, yielded viable seeds. The 12 cohorts of flowers contributed markedly different amounts to plant yield. Early and later cohorts contributed much less than did middle cohorts in terms of marketable pod dry weight and numbers of fully developed seeds, aborted seeds, and undeveloped ovules. Peak productivity was therefore obtained from the middle phase of flowering in these annual bean plants. The lower pod yield of later cohorts is interpreted as a result of competition for limited resources between maturing pods and new flowers. We consider possible causes for the various fates of flowers and ovules and discuss flowers as plant modules suitable for demographic examination.     

GROWTH PATTERNS OF PEA SEEDLINGS IN DARKNESS AND IN RED AND WHITE LIGHT

Thomson , Betty F., and Pauline Monz Miller . (Connecticut Coll., New London.) Growth patterns of pea seedlings in darkness and in red and white light. Amer. Jour. Bot. 48(3): 256–261. Illus. 1961.—Seedlings of peas were grown in vermiculite at 22°C. and exposed 16 hr. daily to red or white light or kept in darkness. Others were grown in soil in the greenhouse. Samples harvested daily to 16 days were dissected, the length of each internode and leaf measured and the total number of leaves and leaf primordia counted. The form of the stem apex and youngest primordia and interrodes is the same in light as in darkness. Leaf production is accelerated very slightly and the growth of leaves and internodes is decidedly accelerated by light. Leaf-leaf, leaf-internode and internode-internode correlations indicate that the morphogenetic effect of light is limited to later stages of organ growth. Dry weight is consumed more rapidly in light than in darkness, probably because of more rapid growth and slightly greater amounts of respiring tissue in light-grown plants.     

MATERNAL INVESTMENT AND FRUIT ABORTION IN PHASEOLUS VULGARIS

Plants lose some of their parental investment through fruit abortion. Resource conservation theory predicts that the maternal plant should abort those fruits furthest from maturity in order to conserve scarce resources. Embryo-quality theory predicts that the maternal plant should favor offspring of particular genotypes. I recorded the patterns of maternal investment in floral cohorts of domesticated and wild beans, Phaseolus vulgaris L. In accord with the resource conservation theory, late pod cohorts have the highest fruit abortion rates. When domesticated beans are grown in smaller pots, late cohort survivorship declines. When domesticated beans are crossed with pollen donors of different degrees of relatedness, the fruit abortion rate is the same even though seeds from the outbred crosses weigh more. The challenge for ecologists is to model and test the combined and possibly conflicting effects of selection for resource conservation and high offspring quality.