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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Plant Sci. | doi: 10.3389/fpls.2019.01290

Grafting cucumber onto pumpkin induced early stomatal closure by increasing ABA sensitivity under salinity conditions

  • 1College of Horticulture and Forestry, Huazhong Agricultural University, China

In the early period under salt stress conditions, reduced stomatal opening could prevent water loss and avoid wilting. ABA signal plays an important role during this process. Here, we show that cucumber grafted onto pumpkin have a more rapid stomatal closure that helps plant adapt to osmotic stress caused by salinity. Accelerated abscisic acid (ABA) contents in the root, xylem sap and leaf were evaluated for the two grafting combinations (self-grafted cucumber and cucumber grafted onto pumpkin rootstock), and four transcript of ABA signaling genes (NCED2, ABCG22, PP2C and SnRK2,1) were also investigated. Results showed that root-sourced ABA signal lead to a decreased stomatal opening and transpiration in the plants grafted onto pumpkin compared with plants grafted onto cucumber. Furthermore, plants grafted onto pumpkin had an increased sensitivity to ABA compared with self-grafted cucumbers. Inhibition of ABA biosynthesis with fluridon in roots increased the transpiration rate (Tr) and stomatal conductance (Gs) in the leaves. Our study demonstrated that the roots of pumpkin have developed an enhanced ability and make the scion more sensitive to ABA that is delivered from root to shoot and enhances osmotic tolerance under NaCl stress. Such a mechanism can be greatly exploited to benefit the vegetable production particularly in semiarid saline regions.

Keywords: salt tolerance, ABA, stomata, Grafting, cucumber, rootstock

Received: 25 Jul 2019; Accepted: 17 Sep 2019.

Copyright: © 2019 Niu, Sun, Nawaz, Sun, Cao, Lu, Huang and Bie. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Zhilong Bie, College of Horticulture and Forestry, Huazhong Agricultural University, Wuhan, Hubei Province, China, biezhilong@hotmail.com