Influence of salt stress on plants of poplar clone "INRA 353-38" and willow clone "Zhytomyrska-1" in in vitro culture

Abstract

Soil salinization is an important abiotic factor negatively affecting plant growth, development and productivity. Fast-growing poplar and willow trees are important plants for bioenergy production demonstrating varying degrees of adaptation to different habitats. The study of salt resistance in different clones of poplars and willows will reveal genotypes that can be planted in saline soils for producing biomass for the bioenergy industry. Therefore, the aim of the study was to investigate the effects of salt stress on poplar plants of clone 'INRA 353-38' (Populus tremula × P. tremuloides) and willow clone 'Zhytomyrska – 1' (Salix sp.) under in vitro culture. For this purpose the plants were cultivated on MS nutrient medium with the addition of sodium chloride in concentrations 25 mM, 50 mM and 100 mM. The control plants were grown on the sodium chloridefree medium. The plant status (with a 4-score scale), the intensity of their growth (by shoot length) and rooting capacity (by the number of roots) were assessed on the 10th and the 30th day of cultivation. The results obtained indicate a high level of sensitivity to sodium chloride of both studied clones under in vitro cultivation. But the willow 'Zhytomyrska – 1' had a higher sensitivity to salt stress comparing to hybrid polar 'ІNRA 353-38' since growth parameters of willow were significantly decreased even under the concentration of sodium chloride 50 mM, and in the case of short term influence (10 days) of the highest concentration of sodium chloride (100 mM) all willow plants terminated their growth and quickly died. The growth parameters of hybrid poplar were declined within a month, mainly under the highest concentration of sodium chloride, but even under such conditions some part of the shoots were able to survive.