The Growth and Metabolism of Excised Roots in Culture. I. The Measurement of Growth and the Role of Certain Vitamins

Abstract

BONNER and DEVIRIAN (3) and BONNER (4) have shown that roots of different species vary appreciably as to the nutrients with which they must be'supplied for satisfactory growth in culture. ROBBINS (13) and WHALEY and LONG (15) have shown that roots of different lines of tomato differ particularly in vitamin requirements. The results do not make it clear as to whether the differences in response to added vitamins represent differences in ability of the roots 'to synthesize these substances for themselves or differences in ability to utilize the supplements. It can be anticipated, however, that if such differences exist among lines within a given species they may play some part in the development of general metabolic differences. It should be possible to study the inheritance patterns of these differences by utilization of root culture techniques in combination with a hybridization program to produce progeny in which these same characteristics can be investigated. The present study has been aimed at detecting the existence of line differences in roots of the tomato, Lycopersicon esculentum Mill. and related species with respect to the ability of the roots to synthesize and/or utilize thiamin, pyridoxine and niacin; at evaluating the significance of such differences; and ultimately at studying the inheritance of these differences.

The Growth and Metabolism of Excised Roots in Culture. Ii. The Respiratory Rates of Excised Tomato Roots

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Early studies on culture methods for, excised roots have been summarized in review papers by WHITE (8,11) and the adaptation of these methods to the experiments described here has been set forth in the first paper in this series (WHALEY, et al,7). The WHALEY, et al,(7).

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“…The WHALEY, et al,(7). The present paper is concerned with the correlations between these growth responses and respiratory rates, and thus with the possible influence of these vitamins on respiration.…”

“…Early studies on culture methods for, excised roots have been summarized in review papers by WHITE (8,11) and the adaptation of these methods to the experiments described here has been set forth in the first paper in this series (WHALEY,et al,7). The method consists of growing roots aseptically in a solution containing inorganic salts supplemented with sucrose, with glycine, and with such vitamins or other accessory growth substances as are under investigation in a particular experiment.…”

“…The root pieces were then removed from the vessels and the volume of the tissue from each Warburg vessel was determind by means of water displacement in a volumeter (WHALEY, et al, 7). After volume measurement the roots were transferred to tared weighing bottles and dried to constant weight at 1050 C. Calculations of oxygen uptake on the basis of volume and of dry weight were made after application of the usual manometric constants.…”