Authors:X. Gong, C. Liu, Y. Wang, X. Zhao, M. Zhou, M. Hong, S. Wang, N. Li, and F. Hong
The mechanism of the fact that Mn deficiency damages the photosynthesis of plants is not yet fully understood. The main aim of the study was to determine Mn deficiency effects in photophosphorylation and key enzymes of CO
assimilation of maize. Maize plants were cultivated in Hoagland’s solution. They were subjected to Mn deficiency and to Mn administered in the Mn-deficient Hoagland’s media. The results showed that Mn deficiency was found to cause extensive declines in plant weight and chlorophyll a content, electron transport and oxygen-evolving rate, photophosphorylation rate, activities of Mg
-ATPase, Rubisco and Rubisco activase, and mRNA expressions of Rubisco and Rubisco activase of maize, but it only slightly affected chlorophyll b and carotenoid formation. However, Mn addition decreased the inhibition of the photosynthesis in maize caused by Mn deficiency.
Authors:H.Q. Zhao, L. Wang, J. Hong, X.Y. Zhao, X.H. Yu, L. Sheng, C.Z. Hang, Y. Zhao, A.A. Lin, W.H. Si, and F.S. Hong
Salt stress impaired Mn imbalance and resulted in accumulation of ROS, and caused oxidative stress to plants. However, very little is known about the oxidative damage of maize roots caused by exposure to a combination of both salt stress and Mn deprivation. Thus the main aim of this study was to determine the effects of a combination of salt stress and Mn deprivation on antioxidative defense system in maize roots. Maize plants were cultivated in Hoagland’s media. They were subjected to 80 mM NaCl administered in the Mn-present Hoagland’s or Mn-deficient Hoagland’s media for 14 days. The findings indicated that the growth and root activity of maize seedlings cultivated in a combination of both salt stress and Mn deprivation were significantly inhibited; the compatible solute accumulation, malondialdehyde, carbonyl, 8-OHdG, and ROS were higher than those of the individual salt stress or Mn deprivation as expected. Nevertheless, the antioxidative enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione reductase, glutathione-S-transferase and antioxidants such as ascorbic acid, glutathione and thiol were lower than those of the individual salt stress or Mn deprivation. In view of the fact that salt stress impaired Mn nutrition of maize seedlings, the findings suggested that Mn deprivation at the cellular level may be a contributory factor to salt-induced oxidative stress and related oxidative damage of maize roots.