MORPHOPHYSIOLOGICAL LEAF CHARACTERISTICSAND NUTRITIONAL STATUS OF SIX WOODY SPECIES AS A FUNCTION OF THE SOIL WATER AVAILABILITY

ABSTRACT

The reduction in water availability effects plant physiology and morphology and accounts for changes in metabolism with implications for the development of tree species. The objective of this study was to evaluate the influence of water stress on morphophysiological leaf characteristics and nutritional status of adult plant of gonçalo-alves (Astronium fraxinifolium), guanandi (Calophyllum brasiliense Cambess.), ipê-amarelo (Handroanthus serratifolius (Vahl.), ipê-rosa (Handroanthus impetiginosa (Mart.) Matos.), marupá (Simarouba amara Aubl.) and mogno (Swietenia macrophylla King.) cultivated under rainfed and irrigated conditions, in the irrigation perimeter of Baixo Acaraú, Ceará. The experimental design was a repeated measures, a scheme of sub-divided plots (6 x 2 x 2), the main plot consists of six species, the sub-plot of two water availability (irrigated and rainfed) and the sub-subplots were the evaluation time. The following evaluations were performed during the dry and rainy seasons: foliar concentrations of N, P, K and Na, specific leaf area (AFE), leaf succulence (GS), and relative index of chlorophyll (IRC). The results showed that ipê-amarelo was the most sensitive species in terms of variation of N, P and K concentrations in leaves in response to soil water availability. Regarding AFE, ipê-amarelo, ipê-rosa and mogno were more sensitive to extreme water deficit conditions. The water restriction in the soil causes the decrease of the leaf succulence in the gonçalo alves and mogno. The chlorophyll is directly affected by drought and is related to the higher GS and the lower AFE. As for A/N and A/P, gonçalo-alves was more efficient species, not affected by soil water availability conditions.

Keywords:
water stress; leaf morphology; mineral nutrition; CO₂ assimilation