Effects of Silicon and Manganese on the Growth and Physiology of Castanopsis hystrix
To explore the effects of silicon and manganese on Castanopsis hystrix seedlings,the growth and physiological characteristics of seedlings treated with different concentrations of silicon and manganese were measured.The results showed that:the relative increase in plant height and ground diameter,the root morphological index,and the SOD,POD,CAT,and APX activities of red cone-shaped plants increased first but then decreased with increasing concentration in the Mn or Si treatment and the presence of MDA contrast agent.Low concentrations of Mn(200,600 μg·g-1)or Si(500,1 000 μg·g-1)were beneficial to the growth and development of red cone-shaped plants,but high concentrations of Mn(1 500,3 000 μg/g)or Si(2 000 μg·g-1)were inhibitory.An appropriate amount of Si(500 or 1 000 μg·g-1)can alleviate the stress caused by a high concentration of Mn and improve physiological indices of inhibited growth.However,excessive Si(2 000 μg·g-1)aggravated the stress.The simultaneous addition of an appropriate amount of Si and Mn significantly promoted the growth and develop-ment of Castanopsis hystrix seedlings,of which 600 μg·g-1 Mn and 500 μg·g-1 Si were the best treatments.The addition of high concentrations of silicon and manganese resulted in severe inhibition.Castanopsis hystrix has a certain Mn tolerance(the Mn addition range is less than 1 500 μg·g-1).Mn ore in some areas of Guangxi has the potential for Castanopsis hystrix pro-duction cultivation and ecological forest application.