African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6576

Full Length Research Paper

Photosynthesis, ion accumulation, antioxidants activities and yield responses of different cotton genotypes to mixed salt stress

Guowei Zhang1, Lei Zhang2, Binglin Chen3 and Zhiguo Zhou*
Key Laboratory of Crop Physiology and Ecology in Southern China of Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, P. R. China.
Email: [email protected]

  •  Accepted: 01 July 2013
  •  Published: 03 December 2013

Abstract

This study analyzes the effects of soil salinity on photosynthetic character, osmoregulation, content of pigment, K+/Na+ ratio, lipoxygenase and antioxidants activities in functional leaves during the flowering and boll-forming stages of two cotton cultivars, namely, CCRI-44 (salt-tolerant) and Sumian12 (salt-sensitive), grown under different soil salinity conditions. In the control plants, non-significant differences were found in gas exchange, saturation irradiance (SI) and carotenoid (Car) content between the two cultivars. However, it showed higher K+/Na+ ratio, antioxidant enzyme activities, soluble sugar and protein contents, and lower chlorophyll (Chl) content and yield in CCRI-44. Salinity stresses remarkably increased soluble sugar and protein contents, lipoxygenase and the antioxidant activities, but decreased K+/Na+ ratio, Chl and Car contents, SI, photosynthetic capacities and yield, the extent being considerably larger in Sumian12 than CCRI-44. Although the soluble sugar, protein contents and the antioxidant activities of Sumian12 elevated more evidently under salt stresses, those variables never reached the levels of CCRI-44. Thus, CCRI-44 could maintain higher seed cotton yield than Sumian12 by sustaining higher osmoregulation and antioxidative abilities, which led to higher photosynthetic capacity. Hence, the salt-tolerant cotton cultivars could harmonize the relationship between CO2 assimilation (source) and the seed cotton yield (sink) under the experimental conditions.

 

Key words: Cotton (Gossypium hirsutum L.), mixed salt stress, salt tolerance, photosynthesis, ion accumulation, antioxidant enzyme activity, seed cotton yield.