Silicon alleviates salt stress in pistachio plants

Document Type: Research Paper

Authors

1 Department of Biology, Payame Noor University, I. R. of Iran

2 Department of Plant Science, University of Tabriz, 51666-14779 Tabriz, Iran

Abstract

In this work, the effects of silicon (Si) supplementation were studied in pistachio (Pistacia vera
L. cv Ahmadaghaii) plants exposed to high salinity stress. Plants were grown in pots under
control and salt (EC=15 dS m-1) conditions without or with Si treatment (0.35 g Na2SiO3 Kg-1
soil) under field conditions. Salt stress reduced the plants’ growth significantly in both –Si and
+Si plants; however, Si-supplied plants had a higher root and shoot dry weight as compared to
those without Si supply under salinity conditions. Salt stress caused a significant reduction of
leaf photochemical activities; however, Si application ameliorated these effects. The reduction
of the net CO2 assimilation rate under salinity stress was alleviated by Si application,
accompanied by an increase in water-use-efficiency. The concentration of Na in the leaves and
roots was significantly reduced by Si, while root K and leaf Ca concentrations were higher in
Si-treated plants under salt stress compared with –Si ones. The activity of antioxidative
enzymes increased under salt stress and Si application caused a further increase, being
significant for superoxide dismutase (SOD). Salt stress induced membrane damage, as was
indicated by a higher malondialdehyde (MDA) concentration. In Si-supplemented plants,
however, the MDA amount did not increase under salt stress. The results indicated that the Simediated
alleviation of salt stress in pistachio plants is related to higher photosynthesis and
water-use efficiency, a reduction of Na uptake and transport, and the stimulation of the plant’s
antioxidative defence capacity.
 

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