PLASTID INCLUSIONS IN EPIDERMAL CELLS OF BETA

Inclusions were found in epidermal plastids of Beta vulgaris L., by the use of the electron microscope. One type of inclusion resembles the membrane-bound plastid inclusions found by others in various meristematic plant cells; the other does not appear to have been described before. The second type of inclusion is not membrane-bound and appears elongated and fibrillar in longisection. The elongated plastid inclusion sometimes becomes quite large. It is postulated that Beta epidermal cells may store two different proteins under some conditions.     

带有白花甜菜染色体片段的栽培甜菜易位系的筛选

本文采用斑点杂交方法,对近100%传递的甜菜单体附加系M14(2n=19)发生分离的后代反转系(2n=18)进行研究,采用随机引物法标记白花甜菜特异探针,对80株反转系进行杂交实验,结果筛选出19个易位系,这19个易位系有待于进一步研究,证明是否带有无融合生殖基因。     

WATER RELATIONS OF TWO CALIFORNIA CHAPARRAL SHRUBS

Water use patterns of two California chaparral shrub species, chamise (Adenostoma fasciculatum H. and A.) and Stanford manzanita (Arctostaphylos stanfordiana Parry), were compared during summer drought. Observations of diurnal and seasonal courses of shoot water potential, leaf conductance and transpiration revealed that chamise was more conservative in water use than manzanita. Evidence obtained cast doubt on a hypothesis previously proposed to explain an anomalous pattern of shoot water potential in chamise.     

ACTION OF FUSICOCCIN ON THE POTASSIUM BALANCE OF GUARD CELLS OF PHASEOLUS VULGARIS

Fusicoccin induces stomatal opening in both the light and dark. The stomatal aperture and K content of guard cells was measured to determine whether the action of fusicoccin in inducing stomatal opening is directly related to the uptake of K by the guard cells. Both detached and attached epidermis was treated with fusicoccin and the K content was determined by staining with cobalt sodium nitrite or by electron probe microanalysis. The K content of guard cells in detached epidermal strips floated on 10 μm fusicoccin in 10 mm KCl and aqueous CH₃OH (0.02%, v/v) increased in the light and dark as the stomata opened. After exposure to fusicoccin for 6 hr in the light, however, the stomata were closed and no K could be detected in the guard cells. The K content of guard cells of attached epidermis painted with fusicoccin also increased as the stomata opened, but the concentration of K in the subsidiary cells was not significantly altered by fusicoccin-stimulated opening. Moreover, painting with fusicoccin did not significantly change the Ca and P content of the guard or subsidiary cells. Stomata of epidermal strips, opened to their maximum width by fusicoccin, showed only a small and temporary closure when transferred to a solution of 10 μm abscisic acid. The use of metabolic inhibitors suggested that energy for the uptake of the K may be provided by both photophosphorylation and oxidative phosphorylation.