Differential responses of contrasting low phosphorus tolerant cotton genotypes under low phosphorus and drought stress

Abstract

Background: Drought is one of the main reasons for low phosphorus (P) solubility and availability.

Aims: The use of low P tolerant cotton genotypes might be a possible option to grow in drought conditions.

Methods: This study investigates the tolerance to drought stress in contrasting low P-tolerant cotton genotypes (Jimian169; strong tolerant to low P and DES926; weak tolerant to low P). In hydroponic culture, the drought was artificially induced with 10% PEG in both cotton genotypes followed by low (0.01 mM KH₂PO₄) and normal (1 mM KH₂PO₄) P application.

Results: The results showed that under low P, PEG-induced drought greatly inhibited growth, dry matter production, photosynthesis, P use efficiency, and led to oxidative stress from excessive malondialdehyde (MDA) and higher accumulation of reactive oxygen species (ROS), and these effects were more in DES926 than Jimian169. Moreover, Jimian169 alleviated oxidative damage by improving the antioxidant system, photosynthetic activities, and an increase in the levels of osmoprotectants like free amino acids, total soluble proteins, total soluble sugars, and proline.

Conclusions: The present study suggests that the low P-tolerant cotton genotype can tolerate drought conditions through high photosynthesis, antioxidant capacity, and osmotic adjustment.

Keywords: Antioxidant system, osmotic adjustment; Cotton; Drought stress; Phosphorus; Photosynthesis.