Effect of Drought Conditions at Boiling Stage on Some Chemical Constituents of Cotton Plant

The investigation was carried out to study the effect of drought conditions at boiling stage on chloroplast pigments and anthocyanin, in leaves, carbohydrate, phenols and total amino nitrogen content in leaves and roots, oil and protein contents in bolls of different ages. Seeds of cv. Giza 75 cotton were sown during 1987 and 1988 seasons in pots of 30 cm in diameter containing 11 kg of soil; after complete germination, thinning was carried out leaving one plant per pot. Plants were subjected to water stress conditions at boiling stage till the sign of wilting, while the control plants were irrigated regularly at this stage without allowing the plants to reach wilting stage and kept in turgid state. The results obtained can be summarized as follows:
1. Drought conditions decreased reducing sugar, nonreducing sugar, total soluble sugar and total amino nitrogen in leaves, while the reverse was true in roots.
2. Drought conditions reduced total and polyphenols content in leaves while it had no effect on phenols compounds in roots.
3. Drought conditions had no significant effect on pigments except total carotenoid in 1987 season.
4. Oil content in seeds of different boll ages decreased as a result of drought in both seasons.
5. In general drought condition increased protein content in 1987 season while the reverse was true in 1988 season.
6. Leaves and roots of wilted plants had more inhibitors as compared to turgid plants.