Impact of Low Concentration of Cadmium on Photosynthesis and Growth of Pea and Barley

Irena Januškaitienė

Abstract


Photosynthetic gas exchange and growth characteristics were examined in pea and barley plants using 1 mM Cd treatment. Plants were sown into neutral peat substrate and at a leaf development stage were treated with 1 mM cadmium concentration solution. Gas exchange parameters (photosynthetic rate; intercellular CO2 concentration; transpiration rate; water use efficiency) were measured with portable photosynthesis system LI-6400 on the fifth day after Cd treatment. Under Cd stress the photosynthetic rate of pea and barley plants decreased by 16.7 % (p < 0.05) and 12.8 % (p < 0.05), respectively, compared to the reference treatments. Photosynthetic response of pea leaves to cadmium stress was slightly different from that of barley. Intercellular CO2 concentration decreased by 27.4 % (p < 0.05) in pea leaves but it increased by 33.5 % (p < 0.05) in barley leaves. Cadmium treatment had no statistical significant effect on the transpiration rate of pea plants, while the transpiration rate of Cd treated barley decreased by 23.1 % (p < 0.05), compared to the reference treatment. CO2 reduction processes of Cd treated pea leaves increased (because intercellular CO2 concentration decreased), but that had no positive effect on a photosynthetic rate, and the photosynthetic rate of pea decreased by 4 % more than that of barley. The changes of dry biomass of cadmium treated plants were weak and statistically insignificant.

Keywords


cadmium, photosynthesis, transpiration, water use efficiency, biomass

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Print ISSN: 1392-1649
Online ISSN: 2029-2139