Protective Action of Silicon on Water Relations and Photosynthetic Pigments in Pepper Plants Induced to Water Deficit

摘要

The aim of the study was to investigate the responses promoted by the external application of silicon on water relations and photosynthetic pigments in Capsicum annuum L. plants submitted to water deficiency. The experimental design used was entirely randomized, with 5 treatments (stress, 0.25 μM Si, 1.00 μM Si, 1.75 μM Si and control). The stomatal conductance was significantly influenced by the silicon, in which it were showed the values of 3.4, 16.4, 16.1, 13.7 and 24.3 mmol/m2/sec in stress, 0.25 μM Si, 1.00 μM Si, 1.75 μM Si and control treatments, respectively. The chlorophyll a level in stress, 0.25 μM Si, 1.00 μM Si, 1.75 μM Si and control treatments presented 4.07, 7.29, 8.04, 7.47 and 8.12 mg g-1 FM, respectively. The results indicated that the silicon increased the tolerance to water deficit, in which the leaf relative water content, transpiration, stomatal conductance, chlorophylls a and b, as well as carotenoids were maintenanced in higher levels, if compared with stress plants. In addition, the ratio chlorophylls a/b under the 1.00 μM Si was to improve that control treatment.