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Salinity and root conductivity: differential responses of a coastal succulent halophyte, Salicornia virginica , and a weedy glycophyte, Raphanus sativus
Author(s) -
Ownbey R. S.,
Mahall B. E.
Publication year - 1983
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1983.tb00898.x
Subject(s) - raphanus , salinity , halophyte , distilled water , soil salinity , relative growth rate , biology , botany , chemistry , growth rate , horticulture , ecology , geometry , mathematics , chromatography
The water relations and growth responses of an extreme halophyte, Salicornia virginica , and a common glycophyte, Raphanus sativus , were comparatively examined in a hydroponic growth experiment employing a broad range of salinities. Root conductivity (in growth solutions and distilled water), expressed sap osmolality, water use efficiency, relative growth rate, and salt uptake were the primary responses monitored. Salicornia responded to increasing salinity by decreasing root conductivity (in the growth solutions) and increasing salt uptake, while water use efficiency and growth rates were minimally affected. The inhibitory effects of salinity upon root conductivity were reversible in distilled water, and, importantly, the highest recovery rates were from plants grown in the moderate and high salinities. Salicornia displayed an enhanced ability to absorb water in distilled water following growth in solutions with elevated salinities. In contrast, Raphanus responded to comparatively small increases in growth solution salinity by drastically decreasing growth rates as well as root conductivity (in the growth solutions), while salt uptake and water use efficiency increased under the moderate salinity level. In Raphanus the inhibitory effects of increased salinity upon root conductivity were only partially reversible in distilled water, and the highest recovery rates were from plants grown in the low salinity Thus, once salinity stress was withdrawn, Raphanus exhibited a suppressed ability to move water through the roots. The results are discussed in the light of selected, commonly proposed mechanisms of salinity‐induced growth inhibition.