CREŞTEREA PLANTELOR DE SOIA ŞI MODIFICĂRILE CONŢINUTULUI DE AMIDON INDUSE DE APLICAREA FOSFORULUI ŞI FIERULUI ÎN CONDIŢII SUBOPTIMALE DE UMIDITATE

Abstract

Soybean (Glycine max. L.,) is a tropical legume and it is susceptible to environmental stresses. Dry matter (DM) production and starch contents in plant parts of two soybean cultivars were determined during reproductive stage inrelation to phosphorus (P) and iron (Fe) supply under water stress conditions. Soybean plants were represented by Zodiac and Licurici cultivars differing in potential of productivity. Plants were grown in a soil cultural with either a non-limiting or low P supply and harvested at pod setting stage development. The Licurici cultivar produced a higher DM than the Zodiac in well-watered conditions. Leaves growth and expansion were sensitive to both abiotic factors than roots. No difference between cultivars was detected on the total DM in treatments with adequate P supply (100 mg P kg soil) under water stress. The starch concentration in the plant tissues exhibited differences between both cultivars with Licurici generally having lower levels in roots. P deficiency increased starch contents in leaves irrespective of water regime. We concluded that adequate P and Fe supply decreased the carbohydrates concentration in nodules and support a vigorous roots system growth.