Silicio e déficit hídrico no metabolismo fotossintético e crescimento de chia

Abstract

The availability of water and the sowing time can be limiting factors for the cultivation of chia (Salvia hispanica L.) making it necessary to mitigate the possible damage during and emergence and growth of plants. Thus, the objective was to evaluate the effect of silicon doses associated with different water retention capacities and times of the year in the emergence and photosynthetic metabolism of chia plants. The experiment was carried out from two sowing times (Ep1 and Ep2, January and May 2019, respectively) under four water retention capacities (CRA) (25, 50, 75 and 100%) combined with four doses of silicon (0, 100, 150 and 200 kg ha-1). The characteristics of emergence, photosynthetic metabolism and growth were evaluated. It was observed that the percentage of emergencies in Season 1 (Ep1) was higher with the increase in CRA, and Season 2 (Ep2) provided the best results for emergencies. The water retention capacity of 100% and grown around the 100.00 kg ha-1 silica dose provided greater gas exchange and plant growth. The photosynthetic rate of plants in season 1 did not vary significantly between doses of Si in CRA by 50%. In season 2, the maximum internal concentration of CO2 (Ci) was observed for the 50% CRA and the rubisco carboxylation efficiency (A / Ci) had no significant effect on the 50% CRA. Season 2 provides the best results for chia emergence. The 100% water retention capacity associated with the 100 kg ha-1 silicon dose provided greater efficiency in gas exchange and plant growth. Silicon mitigated the water deficit for number of leaves and leaf area in season 1. For initial fluorescence, relative water content in leaves, number of leaves and leaf area in season 2.