Journal of Environmental Biology

Effect of water stress on carbon isotope discrimination and its relationship with transpiration efficiency and specific leaf area in Cenchrus species

Archana Dubey and Amaresh Chandra*

Indian Grassland and Fodder Research Institute, Jhansi-284 003, India

(Received: March 20, 2006; Revised received: February 02, 2007; Accepted: February 22, 2007)

Abstract: Carbon isotope discrimination (CID) has been proposed in estimating transpiration efficiency (TE) in plants indirectly. To identify variations for TE and specific leaf area (SLA) and their association with CID, a glasshouse experiment was conducted using six prominent species of Cenchrus. A significant increase in TE (3.50 to 3.87 g kg^-1) and decrease in SLA (219.50 to 207.99 cm² g^-1) and CID (13.72 to 13.23‰) was observed from well watered to stress condition. Results indicated a direct relationship of SLA with CID (r = 0.511^* and 0.544^*) and inverse relationship between TE and CID (r =-0.229 and -0.270) However, the relationship of TE with CID was insignificant.  A positive and significant relationship was visualized between TE and dry matter production in both control (r = 0.917^**) and stress (0.718^**) treatments. Relationships of total dry matter with SLA and CID were monitored insignificant and negative in control and positive in stress treatment indicated difference in dry matter production under two treatments. It seems that, in Cenchrus species, CID was influenced more by the photosynthetic capacity than by stomatal conductance, as indicated by its positive relationship with SLA in both control (r = 0.511^*) and stress (r = 0.544^*) conditions and negative relationship with root dry matter production under control (r = -0.921^***) and stress (r = -0.919^***) condition. Results showed good correspondence between CID and SLA, indicating that lines having high TE and biomass production can be exploited for their genetic improvement for drought.

Key words: Carbon isotope discrimination, Cenchrus species, Specific leaf area, Transpiration efficiency

PDF of full length paper is available with author (amaresh62@yahoo.com)

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