THESIS AND DISSERTATIONS/TESES E DISSERTAÇÕES
TITLE: Variations in both carbohydrate and enzymes of the underground organs of Cochlospermum regium (Mart. & Schr.) Pilger in different stages of development
AUTHOR: Carluce Gomes de Sá e Carvalho
DATE: October 10, 1986
PLACE: Botany - USP
EXAMINER BOARD:
Sonia Machado de Campos Dietrich (Adviser) - IBSP
Maria de Fátima A. Pereira - UNICAMP
Antonio Salatino - USP
Rita de Cássia L. Figueiredo-Ribeiro - IBSP
Kurt Gunther Hell - USP
ABSTRACT - The composition and the variations in both carbohydrate content and activities of three hydrolytic enzymes (amylase, starch phosphorylase and invertase) in the underground organs of Cochlospermum regium (Mart. & Schr.) Pilger, a species of the cotton plant found in the "cerrado" of Brazil, were examined in this research.
The plants were collected from the "cerrado" in Goiânia (GO) county, and analysed in the "Seção de Fisiologia e Bioquímica" at the "Instituto de Botânica de São Paulo (SP)". The underground organs studied were grown under different environmental conditions and were examined in three distinct phases, 1 - underground organs of different dimensions and in the "cerrado" condition; 2 - in the first year of plant development and in the "cerrado" condition; 3 - in different phenological stages in experimental conditions.
It was observed that loss of leaves and the entry into the dormant stage did not seem to be a result of the water shortage that occurs in the "cerrado" but rather of the progressive shortening of the photoperiod and lowering in temperature.
The metabolism of the underground organs of C. regium seems to be directed towards the synthesis of starch. It was observed that the soluble sugar content relative to the total dry matter declined with the increase in size of the underground organ and during the dormant stage, and that this process was accompanied by an increase in starch content.
The free water-soluble sugars found in the underground organs of C. regium were glucose, fructose, sucrose and raffinose. In organs from plants in their first year of development, as well as those more highly developed, the relative content of glucose and fructose decreased as the size of the underground organ increased, and during dormancy. When the plants sprouted, these sugars increased, probably as the result of starch hydrolysis. The water-soluble polysaccharides found after hydrolysis were glucuronic acid, galactose, glucose, arabinose and xylose, all of which varied in amount according to the stage of growth of the plant.
During dormancy, pectic substances increased in the more highly developed underground organs; whereas, they decreased in those plants which were in their first year of development.
Similarly, the hemicellulose content of C. regium decreased as the underground organ developed and during dormancy, but increased again when the plant sprouted. A and B hemicelluloses were composed of the following sugars: glucuronic acid, rhamnose, arabinose, xylose, mannose, galactose and glucose. Of these, the xylose was the principal component. Xylose content in the A hemicellulose increased during dormancy and decreased at the start of sprouting in the underground organs of plants in the first year of development. Xylose content in the B hemicellulose decreased during dormancy and increased at the start of sprouting.
Amylase activity was found only in small underground organs. At sprouting, there was an increase in amylolytic activity in plants in their first year of development. This coincided with a decrease of starch content.
Starch phosphorylase isoenzymes were found only in the less developed underground organs. Thus in C. regium underground organs, starch phosphorylase seems to be correlated with the synthesis of starch but only in the early stage of development of the storage organs. During dormancy, there was a decrease in the number of starch phosphorylase isoenzymes, which disappeared from underground organs when the plant sprouted.
Alkaline invertase activity was not found. Acid invertase activity decreased with the growth of the underground organ as well as during dormancy. This activity increased at the start of sprouting in plants which were in their first year of development.
Total protein content of the dry matter increased as the underground organ increased in size. In the larger underground organs, the amount of total protein decreased during the dormant stage. In plants in their first year of development, the amount of total protein increased at this same phenologic stage.
It was suggested that plant age and environmental conditions seem to have some influence on carbohydrate metabolism in C. regium underground organs.
Publication Dates
-
Publication in this collection
17 June 2011 -
Date of issue
Dec 1988
