MORPHOLOGICAL AND PHYSIOLOGICAL RESPONSES OF Argemone ochroleuca SWEET TO WATER DEFICIT

Abstract

In Texcoco, state of Mexico, when the rainfall is scarce, Argemone ochroleuca Sweet invades farmlands during the winter, when rainfall is scarce; therefore, it is assumed that this species has mechanisms to tolerate limiting soil moisture conditions. This research aimed to identify the morphological and physiological effects caused by water deficit in A. ochroleuca during the vegetative phase. The experiment was carried out in a controlled environment chamber from seeds germinated in the laboratory. Seeds with visible radicle were transplanted into PVC tubes with sandy soil as substrate and after 30 days they were separated into two groups, for irrigation and water deficit. Six samplings spaced at seven days were carried out. The experimental design was completely randomized with five replications, and each tube with one plant constituted an experimental unit. The soil water potential (ψ_as) was approximately 16, the stomatal conductance (g_s) 2.3, the water potential of the shoot (ψ_av) 0.4 and the osmotic potential (ψ_πv) of the shoot 0.4 times lower in the treatment of water deficit treatment compared to the control. The concentration of sugars and proline increased as water stress progressed. Under water deficit, the shoot growth of A. ochroleuca decreased by 10 %; however, it contributed to the elongation and thickening of the main root. It is concluded that the physiological qualities and morphological characteristics of Argemone ochroleuca allow it to survive in conditions of limited moisture
and prolonged periods of water deficit.