Title: The synergistic effects of sodium and potassium on the xerophyte Apocynum venetum in response to drought stress

Authors: Yan-Nong Cui, Zeng-Run Xia, Qing Ma, Wen-Ying Wang, Wei-Wei Chai, Suo-Min Wang*

Journal: Plant Physiology and Biochemistry (生物学三区)

Impact Factor: IF^₂₀₁₆=2.724

Abstract: Apocynum venetum is an eco-economic plant species with high adaptability to saline and arid environments. Our previous work has found that A. venetum could absorb large amount of Na⁺ and maintain high K⁺ level under saline conditions. To investigate whether K⁺ and Na⁺ could simultaneously enhance drought resistance in A. venetum, seedlings were exposed to osmotic stress (-0.2 MPa) in the presence or absence of additional 25 mM NaCl under low (0.01 mM) and normal (2.5 mM) K⁺ supplying conditions, respectively. The results showed that A. venetum should be considered as a typical K⁺-efficient species since its growth was unimpaired and possessed a strong K⁺ uptake and prominent K⁺ utilization efficiency under K⁺ deficiency condition. Leaf K⁺ concentration remained stable or was even significantly increased under osmotic stress in the presence or absence of NaCl, compared with that under control condition, regardless of whether the K⁺ supply was sufficient or not, and the contribution of K⁺ to leaf osmotic potential consistently exceeded 37%, indicating K⁺ is the uppermost contributor to osmotic adjustment of A. venetum. Under osmotic stress, the addition of 25 mM NaCl significantly increase Na⁺ accumulation in leaves and the contribution of Na⁺ to osmotic adjustment, thus improving the relative water content, concomitantly, promoting the photosynthetic activity resulting in an enhancement of overall plant growth. These fndings suggested that, K⁺ and Na⁺ simultaneously play crucial roles in the osmotic adjustment and the maintenance of water status and photosynthetic activity, which is benefcial for A. venetum to cope with drought stress.

链接：https://doi.org/10.1016/j.plaphy.2018.11.011