The Sexual Cycle and Intercrossing in the Genus Astrephomene*

SYNOPSIS. The structure and certain aspects of the physiology of the sexual cycle, including mating and zygote germination, were studied in strains of the colonial green flagellate Astrephomene gubernaculifera. Mating type inheritance was analyzed in 4 crosses among strains with 7 chromosomes and 1 cross between strains with 4 chromosomes. Results in all cases indicated that mating type was under the control of a single pair of alleles. Twenty-six morphologically identical clones from separate geographic areas were studied with regard to sexual compatibility. On the basis of intercrossing, 6 sexually isolated groups were recognized. Complete gene flow (genetic compatibility) was found among the strains comprising intercrossing Group I.     

The Physiology of Groundnut

The distribution of labelled assimilates following the assimilation of ¹⁴CO₂ in groundnut (Arachis hypogaea L.) by single leaves at different nodes was investigated using autoradiographic technique. In the vegetative stage growing leaves assimilated most of the ¹⁴carbon, while the fully expanded leaves exported most of its radiocarbon to the apices, young expanding leaves and to the roots. Soon after the formation of the pegs and the growth and development of the pods, the developing pods become the major sinks. At this stage translocation from the foliage of each branch was restricted mostly to the pods produced by this branch.     

光敏色素光转化生理学特性研究进展(英文)

植物主要光受体光敏色素调节植物的多种光调控,使其作出最适宜的光生长,如:光形态建成.光敏色素接受光信号的生物功能基于其红光吸收型(Pr)和具有生理活性的远红光吸收型(Pfr)之间的光可逆式光转化.依据光生物学的标准该转化过程与光合作用相比是一个低能光反应过程,而且其间产生的中间过渡态和光敏色素的亚库可能反过来影响光转化的过程而最终表现出生理功能.在此,主要综述了近年来运用时间分辨动力学特别是差分荧光和光化学,研究光敏色素及其中间过度态光生物物理和光生物化学特性的若干进展,讨论了光信号转导的原初光反应的机理.     

The Physiology of Hormone Receptors

SYNOPSIS. Hormone retention by various target tissues has beendemonstrated for a number of sex steroids. Retention of thesteroid by the target tissue appears to be specific and saturationoccurs at physiological levels of hormone. Thus, target tissuesare said to possess specific receptors for the hormone. Onlythe estrogens have been extensively studied, and both a cytoplasmicand nuclear receptor have been described for various estrogentarget tissues (uterus, pituitary, hypothalamus). The receptorconcept has been utilized by a number of laboratoriesas a mechanismwhich might be helpful in understanding the relationship betweenestrogen effects, i.e., changes in physiology or behavior resultingfrom estrogen treatments. The basis for the estrogen receptoris reviewed along with the data which attempt to relate hormoneretention to a physiological response. There is considerableevidence that hormone retention is a primary step in the tissuehormone interaction as in its absence the effects attributableto the presence of the hormone are not observed. Progesteroneretention has also been demonstrated forsome target tissues,and an estrogen (priming) component is apparent for uterus andvagina. Todate there is no concrete evidence lor specific progesteroneretention at the neural level.