Leaf anatomy and physiology of garlic cultivars related to tolerance to environmental factors

Anatomia e fisiologia foliar de cultivares de alho relacionadas à tolerância a fatores ambientais

Abstract

The objective of this work was to evaluate the physiological and anatomical characteristics of garlic cultivar leaves that indicate tolerance or susceptibility to environmental factors. The experiment was conducted in a greenhouse in a completely randomized design, with eight treatments (cultivars). The evaluated cultivars were Amarantes, BRS Hozan, Caçador, Crespo, Chinês Folha Fina, Chonan, Gigante Roxo Escuro, and Ito. The following physiological variables were evaluated: net photosynthetic rate, stomatal conductance to water vapor, transpiration, internal and external carbon, and water use efficiency. The anatomical characteristics were analyzed with a microscope coupled to a camera. The Chinês Folha Fina, Chonan, Gigante Roxo Escuro, and Crespo cultivars showed higher mean photosynthetic rates and thicker photosynthetic tissues than the others. The Chonan and Crespo cultivars stood out for their higher photosynthetic rates, higher stomatal indices, thicker cuticle and epidermis, and larger mesophyll intercellular spaces, which are characteristics common to plants tolerant to water deficit. The characteristics of the Chonan and Crespo garlic cultivars are related to drought tolerance, and those of BRS Hozan, Ito, and Caçador to susceptibility.

Index terms
Allium sativum; chlorophyll parenchyma; photosynthesis; transpiration