TY - JOUR
T1 - Zinc alleviates cadmium toxicity by modulating photosynthesis, ROS homeostasis, and cation flux kinetics in rice
AU - Adil, Muhammad Faheem
AU - Sehar, Shafaque
AU - Han, Zhigang
AU - Lwalaba, Jonas Lwalaba Wa
AU - Jilani, Ghulam
AU - Zeng, Fanrong
AU - Chen, Zhong-Hua
AU - Shamsi, Imran Haider
PY - 2020
Y1 - 2020
N2 - Understanding of cadmium (Cd) uptake mechanism and development of lower Cd crop genotypes are crucial for combating its phytotoxicity and meeting 70% increase in food demand by 2050. Bio-accumulation of Cd continuously challenges quality of life specifically in regions without adequate environmental planning. Here, we investigated the mechanisms operating in Cd tolerance of two rice genotypes (Heizhan-43 and Yinni-801). Damage to chlorophyll contents and PSII, histochemical staining and quantification of reactive oxygen species (ROS), cell viability and osmolyte accumulation were studied to decipher the interactions between Cd and zinc (Zn) by applying two Cd and two Zn levels (alone as well as combined). Cd2+ and Ca2+ fluxes were also measured by employing sole Cd100 (100 μmol L−1) and Zn50 (50 μmol L−1), and their combination with microelectrode ion flux estimation (MIFE) technique. Cd toxicity substantially reduced chlorophyll contents and maximal photochemical efficiency (Fv/Fm) compared to control plants. Zn supplementation reverted the Cd-induced toxicity by augmenting osmoprotectants and interfering with ROS homeostasis under combined treatments, particularly in Yinni-801 genotype. Fluorescence microscopy indicated a unique pattern of live and dead root cells, depicting more damage with Cd10, Cd15 and Cd15+Zn50. Our results confer that Cd2+ impairs the uptake of Ca2+ whereas, Zn not only competes with Cd2+ but also Ca2+, thereby modifying ion homeostasis in rice plants. This study suggests that exogenous application of Zn is beneficial for rice plants in ameliorating Cd toxicity in a genotype and dose dependent manner by minimizing ROS generation and suppressing collective oxidative damage. The observations confer that Yinni-801 performed better than Heizhan-43 genotype mainly under combined Zn treatments with low-Cd, presenting Zn fortification as a solution to increase rice production.
AB - Understanding of cadmium (Cd) uptake mechanism and development of lower Cd crop genotypes are crucial for combating its phytotoxicity and meeting 70% increase in food demand by 2050. Bio-accumulation of Cd continuously challenges quality of life specifically in regions without adequate environmental planning. Here, we investigated the mechanisms operating in Cd tolerance of two rice genotypes (Heizhan-43 and Yinni-801). Damage to chlorophyll contents and PSII, histochemical staining and quantification of reactive oxygen species (ROS), cell viability and osmolyte accumulation were studied to decipher the interactions between Cd and zinc (Zn) by applying two Cd and two Zn levels (alone as well as combined). Cd2+ and Ca2+ fluxes were also measured by employing sole Cd100 (100 μmol L−1) and Zn50 (50 μmol L−1), and their combination with microelectrode ion flux estimation (MIFE) technique. Cd toxicity substantially reduced chlorophyll contents and maximal photochemical efficiency (Fv/Fm) compared to control plants. Zn supplementation reverted the Cd-induced toxicity by augmenting osmoprotectants and interfering with ROS homeostasis under combined treatments, particularly in Yinni-801 genotype. Fluorescence microscopy indicated a unique pattern of live and dead root cells, depicting more damage with Cd10, Cd15 and Cd15+Zn50. Our results confer that Cd2+ impairs the uptake of Ca2+ whereas, Zn not only competes with Cd2+ but also Ca2+, thereby modifying ion homeostasis in rice plants. This study suggests that exogenous application of Zn is beneficial for rice plants in ameliorating Cd toxicity in a genotype and dose dependent manner by minimizing ROS generation and suppressing collective oxidative damage. The observations confer that Yinni-801 performed better than Heizhan-43 genotype mainly under combined Zn treatments with low-Cd, presenting Zn fortification as a solution to increase rice production.
KW - cadmium
KW - cells
KW - chlorophyll
KW - rice
KW - zinc
UR - https://hdl.handle.net/1959.7/uws:57469
U2 - 10.1016/j.envpol.2020.114979
DO - 10.1016/j.envpol.2020.114979
M3 - Article
SN - 1873-6424
SN - 0269-7491
VL - 265
JO - Environmental Pollution
JF - Environmental Pollution
M1 - 114979
ER -