Dinâmica hídrica vascular de diferentes genótipos de oliveira na Região Sul do Brasil

Abstract

Embolism in angiosperms, specifically in olive trees, becomes a limiting factor in achieving the expected productivity and regularity in regions that do not meet the soil and climatic production aspects, as seen in the Southern region of Brazil. The objective of this study, consisting of two chapters, was, in the first chapter, to determine the hydraulic dynamics of xylem through histomorphometric analysis of xylem vessels and to determine theoretical hydraulic conductivity. In the second chapter, the aim was to determine the response of native hydraulic conductivity, maximum conductivity, and loss of hydraulic conductivity. The assessments were carried out on three olive tree varieties during the year 2022, in Pelotas region of Rio Grande do Sul, Brazil. Based on the results of histomorphometric analysis, it was concluded that the anatomy of xylem conducting vessels in olive trees revealed interspecific differences among varieties in terms of vessel area, diameter, and theoretical hydraulic conductivity. Vessel elements with the most significance for the safety and survival of olive trees are those with smaller diameters, ranging from 0 to 22 µm. Vessel elements between 22 and 44 µm are responsible for more than 50% of the total flow. In terms of wood density, there was no difference among the three varieties. The response of native hydraulic conductivity, maximum conductivity, and specific hydraulic conductance varied temporally, seasonally, and intraspecifically.