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This study evaluated the influence of Azospirillum lipoferum on the growth of Myracroduon urundeuva (Anacardiaceae) plants under drought stress, by means of biometric, physical–chemical and biochemical parameters. The association of A. lipoferum with the roots of the plants provided increases of 30% root length, 50% root dry weight, 34% shoot dry weight and 10% soluble protein content. The inoculated plants still maintained 5% higher leaf water potential than those not inoculated and lower membrane damage. Furthermore, the inoculated plants shown less leaf fall and dark green leaves, confirmed by maintenance of the highest levels of chlorophyl a, b and total. On the other hand, superoxide dismutase activity was significantly lower in the inoculated plants, possibly due to the induction of a non-enzymatic protective feature. In this way, the inoculation of PGPR in M. urundeuva can be an alternative for the production of plants that are more tolerant to drought stress.

The objective of this research was to evaluate the productive response associate to biochemical indicators and oxidative enzymes activities involved in the water deficit resistance in eight sugarcane varieties (RB951541, RB931011, RB962962, RB867515, RB763710, RB72454, RB863129, and RB92579) grown in the semi-arid regions of Brazil. Compared to all other varieties, RB763710 was superior in the number of stems m-1, mean height, and stem diameter, production of whole plant fresh biomass and stem. When biochemical responses were obtained, all sugarcane varieties had a statistically similar solubility and maturity, regardless of the specific maturity rate of each cultivar. The increase in soluble carbohydrate levels occurred in the most stress-sensitive varieties and the variety RB763710 had the highest proline content. A lower general correlation was observed between the production of fresh biomass of stalks and the enzymatic activity. Among the varieties, RB763710 had the highest enzymatic activities which possibly provided greater tolerance to water stress due to the ability to maintain the redox state in the leaves of plants under water deficit. The study of the adaptation mechanisms of sugarcane against water deficit has contributed to the development and diffusion of genotypes tolerant to rainfed conditions, thus contributing to increased productivity even under adverse conditions, allowing maintenance and optimization of the production chains of sugarcane in rainfed regions.