R Khavarinejad, R. Shekaste-Band, F. Najafi, Z Gharari,
Volume 13, Issue 1 (5-2013)
Abstract
In order to understand some physiological mechanism of chilling and cold sensitivity in plants we investigate the effects of chilling and cold stress on chlorophyll and proline content, lipid peroxidation and variable chlorophyll fluorescence (Fv/Fm) of Arabidopsis (thaliana L.) The four weeks-old plants (WT, and four chilling sensitive mutants [chs2-2], [chs2-1], [chs1-2] and [chs1-1]) were subjected to two different low temperature treatments (control (23̊ C), chilling (13̊ C) and cold (4̊ C)), for one week. Fv/Fm and chlorophyll content changed significantly in all mutants except in WT by chilling stress (13̊ C), compared with control and 4̊ C treatments. Two out of four mutants, chs1-1 and chs1-2, had lowest chlorophyll content and Fv/Fm value among the tested genotypes. The proline content increased in all mutant genotypes, as well as in WT by chilling stress and 4̊ C, compared with control. MDA content of shoots changed dramatically in all mutant genotypes except in WT by chilling stress, compared with control and 4̊ C treatments. Our findings showed that two mutants, chs1-1 and chs1-2, have had highest chilling sensitivity among the tested genotypes and had the highest proline and MDA contents. It is possible that some damages in photosynthetic systems and/or in proline metabolism via mutation cause these plants more sensitive to chilling and cold stress
Fatemeh Ghasemi, Reza Heidari, Rashid Jamei, Latifeh Poorakbar,
Volume 15, Issue 1 (4-2015)
Abstract
To assess nickel-induced toxicity in plants, Zea mays seeds after germination were cultured on hydroponic nutrient solution with nickel concentrations of 0, 50, 100 and 200 micro molar for a period of two weeks. Then its effect on the growth, Hill reaction and photosynthetic pigment's content were investigated. The fresh and dry weight of leaves and roots increased in 50 &muM nickel but decreased in 100 and 200 &muM. The decline in length of root and shoot were observed by increasing Ni concentration.According to results, root and shoot showed differential growth response to varried concentrations of nickel. Ni concentrations up to 100 &muM caused incrtease in the content of chlorophyll a, but it was decreased at 200 &muM Ni. No significant changes in chlorophyll b and carotinoids content observed. The rate of Hill reaction as an ability of chlorophyll a in the reaction center of PSII680 to split water, decreased by increasing Ni concentration.
