Anatomical characterization of rice plants under conditions of water deficit and water lamina

Abstract

The rice (Oryza sativa L.), can be grown in waterlogged soil or not. The anatomical  characterization  of rice under two water management conditions was the main objective of this research in order to observe changes associated with adaptation to water stress. The cultivars ʹFundarroz  PN-1ʹ, ʹCimarronʹ,  ʹFonaiap 2000ʹ and 4 experimental lines were evaluated, transplanted in the field under two conditions,  without stress (flooding) and stress (intermittent irrigation). Samples of leaves and roots of five plants at 42, 63, 88 and 95 days after transplantation were studied. Samples were dehydrated in tertiary butyl alcohol, embedded in paraffin blocks, cut and stained with Safranin-Fatsgreen  technique. Observations and measurements were made with the program MOTIC 2.0. Collected data were: leaf and leaf central rib sizes, number of spaces, and numbers of vascular bundles (NVB) in the rib and blade, bulliformes cell numbers;  in roots, number of xylem bundles, aerenchyma arrangement, and thickening of endodermis and thickness of the layer surrounding endodermis were measured. To identify the anatomical characters of greater variation among genotypes and irrigation conditions descriptive statistics was used. The NVB and thickening of the endodermis were the characters that showed greater variation, it was observed an increase of the NVB in first-and second-order stress conditions. Fonaiap 2000 and Somaclone 2 were the only genotypes that showed third-order vascular bundles. Changes in the thickening of the endodermis could be associated with tolerance to water deficit.