Germinação e desenvolvimento de soja, Glycine max (L.) Merr. (Fabaceae), cultivar BR 11, em regime diferencial de luz e com simulação de herbivoria.

Abstract

The photosynthesis in the plant is directly influenced by the type and intensity of light wave that reaches the leaves. Direct or indirect radiation from the sun can change the way the plant reacts to the environment, interfering with its metabolism. The study of the reaction of plants to different light regimes is important to understand their development in integrated planting systems and helps determine the planting stand. The objective of this work was to compare soybean germination and development in two different light regimes, in full sun and shade. For this, a lot of seeds were planted in an open location with direct light, and another lot was planted in a greenhouse with indirect light. The two seed lots were close to each other and with simultaneous artificial irrigation. In both lots different hebivory levels were simulated in the middle of the cycle. The germination speed in the two environments, height, number of leaflets, resistance to foliar perforation and mortality before and after the simulated herbivory were analyzed. The germination in the shaded environment was faster due to the lower evaporation, having water available for longer compared to the sunny environment. However, to try to compensate for the lower sunlight, the shaded plants release more leaflets and smaller leaflets, they had the stem sowing with loss of support and very low production of flowers and pods. The plants in the shade did not register at any level of herbivory and all died. We conclude that the tested variety should be grown in full sun to achieve adequate stem height while maintaining its support, with greater resistance to leaf tissue penetration, and producing more pods because it can allocate more photosensitive material compared to the plants in the shaded area of ​​the greenhouse.