海水处理对沼泽小叶桦苗木生长和生理的影响

目的]了解沼泽小叶桦(Betula microphylla var.paludosa)在海水处理土壤和海水处理叶片两种条件下的生长和生理响应,为耐盐树种的选择与应用提供依据.方法]用稀释成不同盐度(含盐量)的海水对1.5年生的沼泽小叶桦扦插苗进行根系浇灌和叶片喷雾处理.根系浇灌处理的盐度为盆栽基质质量的0％(CK)...

Effects of seawater on growth and physiology of Betula microphylla var. paludosa cutting seedlings

【Objective】 The aim of this research is to study the growth and physiological responses of Betula microphylla var. paludosa exposed to salt stress in seawater and provide the basis for the selection of seawater-tolerant tree species. 【Method】 Seawater diluted to different salinities (salt content) was used for root irrigation and leaf spray treatment of 1.5-year-old B. microphylla var. paludosa cutting seedlings. The root irrigating salinity was 0% (CK), 0.2%, 0.4% and 0.6% (mass fraction, same as below), respectively. The salinity of spray treatment on the leaves was 0 (CK), 3.07, 6.14, and 15.35 g/L, respectively. We observed morphological changes in the cutting seedlings and measured their growth and physiological indexes. 【Result】 When the salinity of the soil seawater treatment was below 0.6%, and the salinity of the leaf seawater treatment was below 6.14 g/L, the cutting seedlings suffered less salt damage and survived completely. Low salinity (0.2%) of seawater treatment on the soil could increase the content of chlorophyll and soluble protein in leaves to a certain extent and promote the growth of cutting seedlings. Both seawater treatments on the soil and the leaves could lead to an increase in the relative conductivity of leaves, but the increase in seawater treatment on the leaves had a more significant effect than that on the soil. The malondialdehyde (MDA) content of leaves under seawater treatment on the roots was lower than that of the control treatment (CK), and the MDA content of leaves under the seawater treatment on the leaves was higher than that of CK, but the difference between them was not significant. In addition to the high salinity (15.35 g/L) of seawater treatment on the leaves, the activity of superoxide dismutase in the leaves of other seawater treatments was lower than that of CK. After seawater treatment of the soil and leaves, the peroxidase activity of cutting seedling leaves was higher than that of CK in the early stage and lower than that of CK in the later stage. 【Conclusion】 B. microphylla var. paludosa could withstand soil seawater treatment with a salinity of 0.6% or leaf seawater treatment with a salinity of 6.14 g/L, showing a strong tolerance to seawater, and had substantial application potential in saline land greening.