In vitro response of date palm (Phoenix dactylifera L.) to K/Na ratio under saline conditions

Abstract

Background Salinity is a serious factor limiting the productivity of agricultural plants. One of the potential problems for plants growing under saline conditions is the inability to up take enough K+. The addition of K+ may considerably improve the salt tolerance of plants grown under salinity. It is assumed that increasing the K+ supply at the root zone can ameliorate the reduction in growth imposed by high salinity. The present study aims to determine whether an increase in the K/Na ratio in the external media would enhance the growth of date palm seedlings under in vitro saline conditions.Methods Date palm plants were grown at four concentrations of Na + K/Cl (mol/m3) with three different K/Na ratios. The 12 salt treatments were added to modified MS medium. The modified MS medium was further supplemented with sucrose at 30 g/l.ResultsGrowth decreased substantially with increasing salinity. Growth expressed as shoot and root weight, enhanced significantly with certain K/Na ratios, and higher weight was maintained in the presence of equal K and Na. It is the leaf length, leaf thickness and root thickness that had significant contribution on total dry weight. Na+ contents in leaf and root increased significantly increased with increasing salinity but substantial decreases in Na+ contents were observed in the leaf and root with certain K/Na ratios. This could be attributed to the presence of a high K+ concentration in the media. The internal Na+ concentration was higher in the roots in all treatments, which might indicate a mechanism excluding Na+ from the leaves and its retention in the roots. K/Na ratios up to one significantly increased the leaf and root K+ concentration, and it was most pronounced in leaves. The K+ contents in leaf and root was not proportional to the K+ increase in the media, showing a high affinity for K+ uptake at lower external K+ concentrations, but this mechanism continues to operate even with high external Na+ concentrations.ConclusionIncreasing K/Na ratios in the growing media of date plam significantly reduced the absorption of Na+ less than 200 mM and also balance ions compartmentalization.

Antioxidant System Response and cDNA-SCoT Marker Profiling inPhoenix dactyliferaL. Plant under Salinity Stress

“…High salinity stress caused more reduction in the weight of shoot and root (1.392 and 1.160 g) as compared to control plants (2.697 and 2.201 g), respectively. Alkhateeb et al [ 66 ] performed experiments on P. dactylifera under salinity stress and found that growth declined with increasing salinity stress. Excess salinity affects plants severely due to water stress, membrane disorganization, nutritional disorders, ion toxicity, and the expansion and reduction of cell division [ 67 , 68 ].…”

Influence of salicylic acid (SA) and ascorbic acid (ASA) on in vitro propagation and salt tolerance of date palm (Phoenix dactylifera L.) cv. ‘Nersy’

“…Addition of K + to the salt containing media of date palm has reduced the absorption of Na + and also balanced ions compartmentalization. This improvement in growth is accompanied by a decrease in Na + concentration and an increase in K + concentration in the plant tissues with lower Cl − concentrations in leaves and roots of date palm (Alkhateeb et al, 2015). Some results have revealed the identification of miRNAs that share common biogenesis, structure, and expression features with the miRNAs that have been isolated from other plant species.…”

Comprehensive Analysis of MYB Gene Family and Their Expressions Under Abiotic Stresses and Hormone Treatments in Tamarix hispida

“…This indicated that the expression of the ThMYB13 gene increased the uptake of K + in plants and reduced the accumulation of Na + . It has been increasingly recognized that plant salt tolerance is directly reflected by the ratio of K + /Na + in the cytoplasm; the higher the ratio of K + /Na + , the higher ability of salt tolerance of the plant ( Ma et al, 2011 ; Mishra et al, 2014 ; Alkhateeb et al, 2015 ; Zang et al, 2016 ). These results indicated that ThMYB13 might play an important role in tolerance to salt in transgenic T. hispida plants.…”