<b>Relations between the potential and temperature of the corn and sorghum leafs submitted water stress</b> - DOI: 10.4025/actasciagron.v29i4.426

Abstract

To evaluate the daily behavior of the water potential in corn and of sorghum plants submitted to water stress, relating with the leaf and ambient temperature, were cultivated, in individual pots in greenhouse, five plants of each species. The plants were kept at field capacity until they reached the stage of four leaves. Between that stadium and close to the wilting point the irrigation was suspended and were monitored daily the ambient temperature (T_am), the water potential in the leaf (Ψ _folha) and the temperature on the leaf sheet (T_foext). The plants whose leaves rolled up had their internal temperature measured (T_foint). The average time of Ψ _folha was calculated for both species relating them with T_foex, Tfoint and the differences among those temperatures. Both species presented behaviors similar to Ψ _folha and between 1pm to 3pm they showed the lowest Ψ _folha. Despite the significant inverse relationship between T_foext and Ψ _folha, in corn, this relationship does not present enough precision to use the measure os Tfoex in the control of the water status of the plant and the Tfoint was inferior to the T_foex, becoming a protection mechanism which allows the plant to maintain its metabolism.