The University of Arizona

Salinity affects development, growth, and photosynthesis in cheatgrass.

K.E. Rasmuson, J.E. Anderson

Abstract


The effects of salt stress on growth and development of cheatgrass (Bromus tectorum L.) were investigated in 2 greenhouse studies. The first study assessed developmental and physiological responses of this grass to 4 salinity levels. Salinity stunted growth through reduced leaf initiation and expansion, and reduced photosynthetic rates. Reduction of photosynthetic rates appeared to be primarily due to stomatal limitation. Salinity also reduced carbon isotope discrimination, indicating long-term effects on conductance and carbon gain. Root growth was severely inhibited by high salinity, resulting in a shift in the root to shoot allocation pattern. The second study investigated growth patterns of cheatgrass in relation to intraspecific variation in salt tolerance using plants grown from seeds collected at non-saline and saline sites. Salinity reduced growth of plants from both environments. However, plants from the saline site accumulated leaf and root area at nearly twice the rate as those from the non-saline site, even in the control group. Because plants were grown in a common environment, growth differences between populations were genetically based. Thus, the potential for rapid growth may enable plants from the saline site to rely on shallow, less saline moisture reserves available early in the growing season.

DOI:10.2458/azu_jrm_v55i1_rasmuson


Keywords


dry matter partioning;salt tolerance;leaf area;weed biology;stomatal conductance;roots;ratios;genetic variation;shoots;soil salinity;Bromus tectorum;photosynthesis;growth;biomass;introduced species

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