Inoculação com Rhizobium sp. de mudas de jurema-preta (Mimosa tenuiflora (Willd.) Poiret) sob déficit hídrico.

Abstract

Due to the disorganized exploitation of caatinga by anthropic activities and adverse climatic conditions, it is necessary the adoption of strategies that make possible to increase the tolerance of seedlings to drought. Among these strategies, the inoculation of legumes with bacteria of the Rhizobium genus is of extreme importance, since this association will allow plants to have better growth conditions, exploration of the soil area and, consequently, greater water uptake. The objective of this research was to analyze the physiological behavior of young seedlings of jurema preta (Mimosa tenuiflora (Willd.) Poiret), inoculated with rhizobium, and under two conditions of water availability. The experiment was conducted in an entirely randomized design, factorial scheme 5 x 2, corresponding to five inoculations and two water treatments. The seedlings were kept in 40 polypropylene pots with capacity for 3.0 dm3 of substrate. Gas exchange, Relative Water Content (RWC), seedling quality parameters (height, dry mass, nodulation and nitrogen content) and Dickson Quality Index (DQI) were evaluated. It was concluded that inoculation with the rhizobium isolate CA19PT and nitrogen fertilization positively influence gas exchange, but did not interfere with growth, biomass production, seedling quality, nodulation and nitrogen content of the aerial part of the plant. The hydric condition of 40%cp reduces transpiration and photosynthesis, with negative reflections on the height and dry mass accumulation of the seedlings, however, without affecting the quality of the seedlings. The jurema preta (Mimosa tenuiflora (Willd.) Poiret) seedlings accumulate more biomass in the roots to the detriment of the aerial part, when submitted to water deficit.