Enhanced salt resistance in apple plants overexpressing a Malus vacuolar Na+/H+ antiporter gene is associated with differences in stomatal behavior and photosynthesis
详细信息 查看全文
- 作者：Chao Li ; Zhiwei Wei ; Dong Liang ; Shasha Zhou ; Yonghong Li ; Changhai Liu ; Fengwang Ma
- 关键词：MdNHX1 ; Na+/H+ antiporter ; Apple ; Salt ; Photosynthesis ; Stomatal response
- 刊名：Plant Physiology and Biochemistry
- 出版年：2013
- 出版时间：September, 2013
- 年：2013
- 卷：70
- 期：Complete
- 页码：164-173
- 全文大小：5165 K
文摘
High salinity is a major abiotic factor that limits crop production. The dwarfing apple rootstock M.26 is sensitive to such stress. To obtain an apple that is adaptable to saline soils, we transformed this rootstock with a vacuolar Na+/H+ antiporter, MdNHX1. Differences in salt tolerance between transgenic and wild-type (WT) rootstocks were examined under field conditions. We also compared differences when ¡®Naganofuji No. 2¡ä apple was grafted onto these transgenic or WT rootstocks. Plants on the transgenic rootstocks grew well during 60?d of mild stress (100?mM NaCl) while the WT exhibited chlorosis, inhibited growth and even death. Compared with the untreated control, the stomatal density was greater in both non-grafted and grafted WT plants exposed to 200?mM NaCl. In contrast, that density was significantly decreased in leaves from grafted transgenic plants. At 200?mM NaCl, net photosynthesis, stomatal conductance, intercellular CO2 concentration, and chlorophyll contents were markedly reduced in the WT, whereas the declines in those values were only minor in similarly stressed transgenic plants. Therefore, we conclude that overexpressing plants utilize a better protective mechanism for retaining higher photosynthetic capacity. Furthermore, this contrast in tolerance and adaptability to stress is linked to differences in stomatal behavior and photosynthetic rates.