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。     

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.     

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.     

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     

AUXIN-INDUCED HYPONASTY OF THE LEAF BLADE OF PHASEOLUS VULGARIS

The lateral margins of immature primary leaf blades of Phaseolus vulgaris L. cv. ‘Pinto’ curve up and in toward the midrib when auxin is applied to the leaf. The leaves are most sensitive to auxin shortly after they first unfold and leaves which have grown to about 60 % or more of their ultimate area no longer give this hyponastic response. The response is specific for auxins and is inhibited by the anti-auxins, trans-cinnamic acid and para-chlorophenoxyisobutyric acid. Ethylene and ethylene-generating compounds failed to induce hyponasty, suggesting the response is due to a positive growth promotion by auxin. Measurements of the distance between the lateral margins of the leaf at its maximum width were used to provide quantitative estimates of the degree of hyponasty. Between 2 and 4 hr after auxin application a direct proportionality was found between the amount of curvature and the logarithm of the indoleacetic acid concentration over the range of 10⁻⁶ to 10⁻³ m. The relative sensitivity of the leaves to different auxins was qualitatively similar to that observed in many straight-growth bioassays. Similar responses were obtained when auxin was applied by a carborundum wounding procedure. Potential applications of this auxin bioassay for investigations of the role of auxin in the normal plagiotropic growth behavior of leaf lamina and of the role of auxin in the initiation of various plant diseases are suggested.     

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.     

DEVELOPMENT OF FLORAL ORGANS IN THE SITES OF LEAF PRIMORDIA IN PINGUICULA VULGARIS

Plants of Pinguicula vulgaris L. have either clockwise or counterclockwise spiral phyllotaxy. The inception of floral primordia occurs in leaf sites as a normal sequence of development. Only two leaf primordia initiated late in the season develop into floral primordia in the following year. They do not represent a direct modification of the apical meristem nor of the detached meristem. The apical meristem continues to produce leaves in the vegetative phase and flowers in the reproductive phase, and thus the plants show a monopodial growth. Axillary buds are not developed in this perennial species and instead additional buds of adventitious ontogeny appear. Such buds are produced on the older leaves of larger plants, and they are extremely useful in the vegetative propagation of the species.     

THE GEOTROPIC REACTION OF RODLESS MICE IN LIGHT AND IN DARKNESS

"Black—short ears—kinky tail—rodless" mice, controlled by "pink eyed—dilute—brown" mice, were tested on an inclined plane in order to determine if they are photically sensitive, and, if so, to get a quantitative expression for their visual receptivity. Rodless and control animals were tested in the dark to obtain an expression for normal geotropic orientation. Light was then introduced to modify these reactions if possible. Under light, the controls failed to orient, whereas the rodless gave reactions almost identical with those in the dark. This test has failed in this experiment to suggest sight in the rodless mouse.