Physico-chemical Aspects of Sex in Plants.

Abstract

of any movement, absence of mitosis (Slifer') and very low rates of respiratory metabolism (Bodine'). The third period begins with the resumption of mitotic activity followed by blastokinesis. After the embryo has revolved, it grows rapidly and engulfs the remaining yolk. The third phase marks the completion of differentiation and embryonic o rganogenesi s.This preliminary report on the glutathione reaction is based upon observations of 13 embryos in early development, 70 embryos in diapause, and 30 in various stages of later development. The nitroprusside test for -SH groups was used and the color lasted from 18 to 90 seconds. All embryos (even those in diapause) gave a definite positive color reaction. The stain was apparently more intense and lasting where the tissues were thicker. Yolk did not stain and embryonic membranes colored only momentarily. It is significant that embryos in all stages of diapause showed an intense color reaction indicating the presence of the protein bound -SH groups. It is possible that the -SH group relates more to potential cell activity, rather than indicating active cell division as postulated.

Effects of Photoperiod and Nitrogen Supply on Growth and Reproduction in the Gherkin

“…Stem length was greater at maturity under long-day than under shortday conditions, a response also noted by MURNEEK (23,29) in soybean and rudbeckia and by WITHROW (40) in a number of other species. Rapid extension of the main axis of the 16-hour plants occurred relatively late in ontogeny as also observed by DANIELSON (11).…”

Chemical Composition of Roots and Tops of Dioecious Lychnis in Vegetative and Flowering Phases of Growth

“…This relationship has also been shown to exist in the tops of flowering, plants of Spinacia (14). The imlportance of phospborus in metabolic processes of plants in general suggests specific importanee in relation to sex.…”

HYDROGEN ION CONCENTRATION AND SEXUAL EXPRESSION IN LYCHNIS DIOICA L

“…Both of these workers used the entire plant above-ground. LOEHWING (19), however, found that, in the case of spinach, the pistillate plants were slightly more acid than the staminate, and in hemp he found the same. Such variations in the findings might be due to factors in the environment under which the plants were grown, since methods of testing were the same.…”

“…In a later work (33) he also found the active acidity of expressed sap of staminate plants to be greater than that of female plants. LOEHWING (19) found that the tops of 15-week-old spinach plants were slightly more acid in the case of the female plants. Likewise in hemp he found that the tops of 10-week-old plants showed a slightly higher pH for the males.…”

“…Considerable work has recently been done on the physico-chemical differences between staminate and pistillate plants of dioecious species in an attempt to formulate an objective statement of the chief sexual contrasts (4,16,19,26,27,28). Although not purely physico-chemical in nature, closely related work stresses the genetical and morphological aspects of the problem (2,3,8,20,22,37).…”