Characteristics of Leaf Stomata and Their Relationship with Photosynthesis in <i>Saccharum officinarum</i> Under Drought and Silicon Application

Abstract

Si and exposed for 60 days under each stress condition such as 100-95, 55-50, and 35-30% of field capacity. For the photosynthetic responses, each leaf was observed and separated into three equal parts (base, middle, and tip). We used intact leaves and were able to assess leaf photosynthetic responses. Under moderate and severe stress conditions, applied Si increased the photosynthesis (base, ∼16-143%; middle, 20-66%; and tip leaf part, 41-71%), transpiration rate (base, 15-97%; middle, 26-68%; and tip leaf part, 6-61%), and stomatal conductance (base, 26-137%; middle, 12-70%; and tip leaf part, 7-75%) in sugarcane plants. Ultrastructural examination of sugarcane leaves using scanning electron microscopy showed the remarkable effects on stomata ultrastructure. Silicon increased plant growth development, photosynthetic efficiency, and biomass/yield, and promoted better adaptation of stomata to drought. This study suggests that the application of Si may be used to increase the stress tolerance of sugarcane plants.