Effects of Iron Chlorine E6 Spraying on Physiological Characteristics and Seed Yield of Deschampsia cespitosa

The alpine wetland ecosystem on the Tibetan Plateau is experiencing degradation due to global warming and human activities. Deschampsia cespitosa (L.) P.Beauv., a tussock grass, represents a promising candidate for managing this degradation in alpine swamps and wetlands. Importantly, studying seed expansion and propagation techniques for D. cespitosa, along with promoting the industrialization of its seeds, could accelerate its application in wetland management practices. Iron chlorine E6 (ICE6) is a novel, natural plant growth regulator structurally similar to porphyrin. This study investigated the effects of ICE6 on the yield and physiological traits of D. cespitosa. Foliar sprays of ICE6 at varying concentrations (0 mg/L for control [CK], 0.02 mg/L [A], 0.04 mg/L [B], and 0.06 mg/L [C]) were applied at the tasseling stage. Treatments A, B, and C displayed higher leaf area and chlorophyll content in D. cespitosa flag leaves compared to the control after spraying with ICE6. Leaf gas exchange rates in treatments A, B, and C were also significantly higher than in the control at the late growth stages of D. cespitosa (30 and 43 days). Sugar content was significantly higher in treatments B and C compared to the control. Treatment B exhibited the highest seed yield (6.59 g) at harvest, while treatment C yielded the greatest dry matter mass (36.67 g) at harvest. Taken together, our findings suggest that ICE6 can improve the dry matter quality and seed yield of D. cespitosa by influencing its chlorophyll content, photosynthetic properties, and sugar levels.