Volume 2, Issue 4
October 1935, pages 343-418
pp 343-368 October 1935
Nine types of Mendelian chlorophyll deficiencies consisting of both unicoloured and variegated forms have been described and their inheritance discussed. Some of these like the “zebra-marked”, lutescent and certain variegated forms are recorded for the first time in rice.
A beginning was made to study the inter-relationships of these types and all possible crosses were made with the albino, virescent yellow and the green and white striped as the parents and studied up to the F3 generation. It was found that while each of the three different types behaved as a simple recessive to the normal green, crosses between any two of them gave green F1 plants segregating in F2 into green and the parental types in the ratio of 9∶3∶4 showing the interaction of two factors. The crosses have further shown that three pairs of factors (Ww, Vv and Gw gw) are concerned in the
pp 369-376 October 1935
pp 377-386 October 1935
By employing the Tillmans-Harris technique, the ascorbic acid content of a number of indigenous plant materials has been determined.
Capsicum frutescens, chilli, approachesCapsicum annuum in its ascorbic acid content:
Among the citrus fruits tried, theSautgur orange, a special variety ofCitrus aurantium and the pumelo (both the albedo and juice) are rich sources of ascorbic acid.
The leaves ofSesbania grandiflora and the leaves and pods ofMoringa pterygosperma possesses about 2 mg. of ascorbic acid per g. of the fresh material. The absence of interfering substances in these materials, especially in the latter, suggests the possibility of their use for the preparation of ascorbic acid and as a standard for titrating indicator solutions.
The Indian gooseberry gives the highest reducing value among the materials tried. The presence, therein, of reducing substances other than ascorbic acid is, however, indicated.
Juices of the Indian gooseberry and the cashew apple exhibit great stability suggesting the existence in them of a mechanism protecting ascorbic acid from oxidation.
Ascorbic acid content of other plant materials are tabulated.
pp 387-402 October 1935
On the basis of the observations recorded the population of plants studied is segregated into representatives of two physiologically distinct classe:—
Short-lived plants:Pisum sativum, Coriandum sativum, Carum copticum, Fœniculum vulgare, Trigonella fœnum grœcum, Hibiscus esculentus, Sinapis alba andRaphanus sativus.
Long-lived plants:Gossypium neglectum, Phaseolus vulgaris, Phaseolus multiflorus andCicer arietinum.
The two classes of plants segregated have a fundamental difference in the drift of the respiratory index of the meristems. In the short-lived plants there is a characteristic decrease in values from an early phase of growth (young stage) and the rate of fall becomes more pronounced before the initiation of the reproductive organs, while in the long-lived species the respiratory index maintains more or less a level value for a considerably long time after germination and shows a decline only towards the end of growth cycle.
The gradient of energy release will govern the period of life-cycle—the steeper the gradient, the briefer the life span and the less steep the gradient, the longer will be the life duration andvice versa.
Longevity is proportional to the initial respiratory energy with which the young organism starts its life, as well as the average rate maintained during the course of the life-cycle. The higher the average rate, the more rapid the expenditure of energy and consumption of materials and briefer the life span; and the lower the rate, the more restricted the release of energy and consumption of materials, the longer will be the duration of life.
The meristematic tissue, in general, has a high initial rate relatively independent of external factors and gives an idea of the genetic constitution of the plant.
On the basis of experimental findings the view is held that apart from inheriting the potentiality for morphological characteristics, an organism also may exhibit a potentiality for a certain rate of metabolism and thereby for a specific duration of life.
pp 403-409 October 1935
pp 410-418 October 1935