Abstract:

Objective: This study aimed to explore the mechanism of Silicon (Si) in increasingthe cold resistance of red sandalwood (Pterocarpus santalinus) seedlings by improving mineral nutrient absorption and distribution. Method: One-year-old seedlings were treated with two levels of Si amount for 6 months, and the variations of 8 mineral elements in the seedlings were measured. Then the seedlings were gradually cooled down to (-3±0.5)℃ and treated with the temperature for 24 h, and 72 h, respectively, and the intracellular concentrations of H⁺and Ca²⁺, and H⁺-ATPases and Ca²⁺-ATPase activities of plasma membrane and thylakoid membrane were detected. Result: The results showed that the relative content of K element of red sandalwood seedlings with Si addition was significantly reduced, and the relative content of Si element, and especially Ca element was significantly increased compared with the control. The activities of plasma membrane H⁺-ATPase and Ca²⁺-ATPase of Si-treated seedlings were significantly higher than those of control, and their reductions were significantly less under low temperature stress, especially for the plasma membrane H⁺-ATPase. Under low temperature stress, the protein content and H⁺-ATPase and Ca²⁺-ATPase activities of thylakoid membrane of control seedlings significantly decreased, while phospholipase-D (PLD) activity significantly increased. Statistical analysis showed that H⁺-ATPase and Ca²⁺-ATPase activities were closely related to Ca²⁺ content, membrane lipid composition and PLD activity. Objective: Application of Si improved the absorption, distribution and balance of mineral elements in red sandalwood seedlings, Si mediated the stability of ion pump activity and other chemical components of plasma and thylakoid membranes of red sandalwood seedlings under low temperature stress.

Key words: red sandalwood, cold resistance, silicon, mineral element, ion pump