Effect of drought stress on photosynthetic characteristics, growth and sugar accumulation of field-grown sweet Sorghum

Massacci, A. and Battistelli, A. and Loreto, F. (1996) Effect of drought stress on photosynthetic characteristics, growth and sugar accumulation of field-grown sweet Sorghum. Australian Journal of Plant Physiology, 23 (3). pp. 331-340.

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Abstract

We studied the effect of drought on photosynthesis, growth, and sugar accumulation in field-grown sweet sorghum (Sorghum bicolor (L.) Moench). Stomata closed when drought stress developed during the day. As a consequence, photosynthesis was reduced. The water use efficiency of drought-stressed leaves was slightly lower than that of controls and this reduction was more pronounced early in the morning and in the evening. This suggested that not only stomata limit photosynthesis under drought: photosynthesis at high CO2 was lower in drought-stressed than in control leaves, suggesting that carbon metabolism was inhibited. Electron transport was also reduced, but an increased number of electrons appeared necessary to fix CO2 under drought. Before anthesis, growth was not affected by drought but, after anthesis, elongation of the last internodes was greater in controls than in drought- stressed plants. Both controls and drought-stressed plants accumulated sucrose and starch in the stem after anthesis. The accumulation was low and ceased early in the stem apex. It is likely that seeds in the panicle compete with the apex for carbon. During panicle maturation sucrose and starch content was higher in drought-stressed than in control stems. At the end of our experiments, however, the sucrose content per plant was similar in all samples. We conclude that sugar accumulation is less sensitive to drought than photosynthesis. Irrespective of drought conditions, (i) before anthesis growth is the predominant sink for photosynthates; (ii) after anthesis sugar accumulation in the stem becomes the preferential sink at the expense of growth of apical internodes

Item Type: Article
Uncontrolled Keywords: Stomata, Photosynthesis, Electron transport, Internodes, Panicle maturation sucrose
Author Affiliation: CNR-Istituto di Biochimica ed Ecofisiologia Vegetali, via Salaria km 29,300, I-00016 Monterotondo Scalo, Roma, Italy
Subjects: Plant Production
Plant Physiology and Biochemistry > Plant Physiology
Social Sciences > Plant Physiology and Biochemistry > Plant Physiology

Plant Physiology and Biochemistry > Biochemistry
Social Sciences > Plant Physiology and Biochemistry > Biochemistry
Divisions: Sorghum
Depositing User: Ms Ishrath Durafsha
Date Deposited: 07 Jan 2014 03:52
Last Modified: 07 Jan 2014 03:56
Official URL: http://dx.doi.org/10.1071/PP9960331
URI: http://eprints.icrisat.ac.in/id/eprint/12286

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