INFLUENCE OF THE TUBERCLE MOTHER OF Solanum cardiophyllum Lindl. ABOUT THE RESPONSE FROM PLANT TO DROUGHT

Abstract

In order to analyze the effect of the mother tuber of Solanum cardiophyllum on plant responses to drought stress, an experiment was carried out under greenhouse conditions at Chapingo, México, during the Spring of 1987. The measured variables were:
a) plant survival percentage; b) aerial and underground dry weight ( excluding tubers), and fresh weight of tubers; ande) water ( ψ_w), solute ( ψ_s) and pressure (ψ_p) potentials. Results showed that plants survival was reduced. by 35%, in the average,. with the elimination of mother tuber under drought conditions; however, plant growth with or without tubers did not suffer significative change as far as to the morphological characteristics are concemed. Moreover, it was found that plants with mother tuber maintained higher ψ_w and ψ_P values, and lower _s values than plants without tuber. These results suggest a better osmotic adjustment capacity than might be attributed to the remobilization of tuber solutes to the aerial portion. lt is concluded that the mother tuber provides not only nourishment for shoot emergence but also constitutes a metabolic and water reservoir that are used by the plant under drought situations.