摘要
In a previous study, a salt stress-induced programmed cell death （PCD） model was established in rice root tip cells. Here, by using Wuyunjing 8th rice seedlings, the effects of lanthanum on salt stress-induced PCD early events were studied. The results indicated that low concentrations （10 μmol/L）, but not high concentrations （100 μmol/L） of LaCl3 could effectively prevent salt stress-induced PCD. Further study demonstrated that in the early stages of salt-induced PCD process, 10 μmol/L of La^3＋ could prevent the increase of cytoplasmic calcium levels, inhibit reactive oxygen species （ROS） production, and enhance the ROS-scavenging enzyme activities such as superoxide dismutases （SOD） and ascorbate peroxidase （APX）. Imidazole （20 mmol/L）, the inhibitor of nicotinamide adenine dinucleotide phosphate-oxidase （NADPH oxidase）, could alleviate the occurrence of PCD obviously, and such alleviation could be enhanced by the addition of La^3＋, indicating the involvement of NADPH oxidase in the salt stress-induced PCD process. Taken together, lanthanum could prevent salt stress-induced PCD occurrence in the rice root tip cells by blocking the calcium influx under stress, which was followed by inhibiting calcium-dependent NADPH oxidase activity to prevent O2^·- production and, enhancing the cytosolic antioxidative enzyme activities to scavenge the reactive oxygen species.
In a previous study, a salt stress-induced programmed cell death （PCD） model was established in rice root tip cells. Here, by using Wuyunjing 8th rice seedlings, the effects of lanthanum on salt stress-induced PCD early events were studied. The results indicated that low concentrations （10 μmol/L）, but not high concentrations （100 μmol/L） of LaCl3 could effectively prevent salt stress-induced PCD. Further study demonstrated that in the early stages of salt-induced PCD process, 10 μmol/L of La^3＋ could prevent the increase of cytoplasmic calcium levels, inhibit reactive oxygen species （ROS） production, and enhance the ROS-scavenging enzyme activities such as superoxide dismutases （SOD） and ascorbate peroxidase （APX）. Imidazole （20 mmol/L）, the inhibitor of nicotinamide adenine dinucleotide phosphate-oxidase （NADPH oxidase）, could alleviate the occurrence of PCD obviously, and such alleviation could be enhanced by the addition of La^3＋, indicating the involvement of NADPH oxidase in the salt stress-induced PCD process. Taken together, lanthanum could prevent salt stress-induced PCD occurrence in the rice root tip cells by blocking the calcium influx under stress, which was followed by inhibiting calcium-dependent NADPH oxidase activity to prevent O2^·- production and, enhancing the cytosolic antioxidative enzyme activities to scavenge the reactive oxygen species.
基金
Supported by the National Natural Science Foundation of China （30400030.） and the Grant to Innovative Young Scholars of Jiangsu Province （BK 2004416.）.
