Bioinsumos aliviam o estresse oxidativo e regulam a fisiologia do trigo exposto ao déficit hídrico

Abstract

Water deficit promotes an increase in reactive oxygen species, which impair the morphophysiology of plants of socioeconomic interest, such as wheat. Thus, studies are needed to establish agents with anti-stress potential, and in this scenario, bio-inputs show promise. We aimed to evaluate the potential of bio-inputs to alleviate oxidative stress and contribute to wheat physiology during and after exposure to water deficit. The seeds were inoculated with the following bio-inputs: i) microalgae Parachlorella sp., ii) Bacillus subtilis, iii) Trichoderma harzianum, iv) Parachlorella sp. + B. subtilis, v) Parachlorella sp. + T. harzianum, and vi) Parachlorella sp. + B. subtilis + T. harzianum, in addition to the control (without bio-inputs), associated with two water regimes: a) irrigated = daily irrigation and b) water deficit (WD): suspension of irrigation. Gas exchange was evaluated during the stress and post-stress phases, and biochemical parameters were evaluated during stress and thousand-grain weight (TGW) during post-stress. Plants under WD had increased malondialdehyde and hydrogen peroxide content. On the other hand, plants inoculated with Parachlorella sp. and Bacillus subtilis, either alone or in combination, reduced these levels, suggesting physiological memory induced by these bio-inputs, alleviating oxidative damage and increasing the efficiency of the defense system through the activation of superoxide dismutase and peroxidase, which contributed to maintaining the photosynthetic rate and stomatal conductance. In the post-stress phase, inoculated plants showed a more efficient resumption of gas exchange. Inoculation with isolated T. harzianum did not mitigate oxidative stress and physiological activity. PMG was not influenced by the treatments, but was numerically lower in plants in DH without bio-inputs. Inoculation of bio-inputs via seeds is a promising practice in inducing physiological tolerance of wheat to water deficit.