Chin J Plant Ecol ›› 2010, Vol. 34 ›› Issue (10): 1204-1212.DOI: 10.3773/j.issn.1005-264x.2010.10.009

• Research Articles • Previous Articles     Next Articles

Mechanism for photoprotection of leaves at the bolling stage under field conditions in Gossypium barbadense and G. hirsutum

ZHANG Ya-Li*(), LUO Yi, YAO He-Sheng, TIAN Jing-Shan, LUO Hong-Hai, ZHANG Wang-Feng**()   

  1. Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, Xinjiang 832003, China
  • Received:2009-12-09 Accepted:2010-02-04 Online:2010-12-09 Published:2010-10-31
  • Contact: ZHANG Wang-Feng


Aims Our principal aim was to test the hypothesis that pima cotton (Gossypium barbadense) and upland cotton (G. hirsutum) have different photoinhibition and photoprotection strategies due to differences in light capturing and photosynthetic characteristics.

Methods We measured diurnal leaf movement, incident photon flux density (PFD) on leaves, leaf temperature, maximal photochemical efficiency of PSII (Fv/Fm), PSII photochemical efficiency (ΦPSII), electron transport rate (ETR), photochemical quenching coefficient (qP), non-photochemical quenching (NPQ), net photosynthetic rate (Pn), stomatal conductance (Gs) and photorespiration (Pr) in pima and upland cotton.

Important findings Upland cotton had higher Pn and Gs than pima cotton. Nevertheless, the ratio of photorespiration rate to gross photosynthetic rate was generally higher in pima cotton. Pima cotton and upland cotton had similar degrees of photoinhibition. Furthermore, pima cotton had generally higher thermal energy dissipation capacity than upland cotton. All results indicated that differences in leaf diaheliotropic movement and Gs in pima cotton and upland cotton resulted in differences of both incident PFD on leaves and leaf temperature. Upland cotton and pima cotton preferentially used electron transport flux and thermal energy dissipation, respectively, for light energy dissipation toward photoprotection to against photoinhibition. Nevertheless, more electron transport flux was distributed into the photorespiration pathway to prevent over-reduction of the photosynthetic electron transport chain and photoinhibition in pima cotton.

Key words: leaf movement, photoinhibition, photosynthesis, pima cotton, upland cotton