Authors: Stasik, Oleg; Jones, Hamlyn G.

Source: Journal of Experimental Botany, Volume 58, Number 8, 24 June 2007 , pp. 2133-2143(11)

Publisher: Oxford University Press

Abstract:

The photosynthetic responses to moderately high temperatures (38 C, imposed at 21% or 2% O₂ in air and 1500 mol m² s¹) were compared in wheat (Triticum aestivum L.) cultivars grown in northern regions of Ukraine and expected to be relatively sensitive to high temperatures (North cultivars) and in cultivars grown in southern regions and expected to be relatively heat-tolerant (South cultivars). Heating intact leaves in 21% O₂ for 1 h decreased CO₂ assimilation by c. 63% in North cultivars and only c. 32% in South cultivars, with a decrease in PSII activity being observed in only one of the North cultivars. Carboxylation efficiency was decreased by about 2.7-fold in North cultivars with no significant effect in South cultivars. The maximum rates of carboxylation by Rubisco in vivo, V_cmax, estimated from Farquhar's model, increased more than 2-fold in South cultivars and remained unchanged in North cultivars while the maximum rate of RuBP regeneration, J_max, decreased by 53% and 21% in North and South cultivars, respectively. Where the heat treatment was imposed in 2% O₂ this increased (as compared with treatment at 21% O₂) the inhibitory effect on CO₂ assimilation in tolerant cultivars, but decreased it in sensitive ones. The results suggested that differences in tolerance of moderately high temperatures in wheat relate to the stability of the Rubisco function and to RuBP regeneration activity rather than to the effects on PSII activity or stomatal control.

Keywords: Heat-tolerance; high temperature; photosynthetic limitation; photosystem II; Triticum aestivum L

Document Type: Research article

DOI: http://dx.doi.org/10.1093/jxb/erm067

Publication date: 2007-06-24

More about this publication?

• The Journal of Experimental Botany publishes high-quality primary research papers in the plant sciences. These papers cover a range of disciplines from molecular and cellular physiology and biochemistry through whole plant physiology to community physiology. Every issue of the Journal contains at least one 'Perspective' article. These are most commonly reviews of research areas, which are particularly exciting and important, topical or controversial. Opinion articles are also considered. In addition to 12 regular issues, at least one Special Issue is published each year. These are collection of articles derived from a specialised meeting or conference session. All papers are fully reviewed, and we will endeavour to complete the review process with all speed.

Related content

• In this: publication
• By this: publisher
• In this Subject: Botany
• By this author: Stasik, Oleg ;  Jones, Hamlyn G.

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers