樟子松幼树株高及其逆境生理指标对沙埋的响应特征

以3龄樟子松幼树为材料,2013年在科尔沁沙地研究了不同沙埋深度下其株高、叶片膜透性、渗透调节物质含量及保护酶活性变化,以揭示沙埋条件下樟子松幼树生长及其对逆境的生理响应特征。结果显示:(1)在沙埋深度低于株高以上2cm时被埋樟子松幼树能够正常生长,其株高和芽长均明显高于非沙埋对照,并以沙埋深度为株高的50%时增长幅度最大;当沙埋深度超过株高2cm以上时,虽然植株高度和芽长也较埋前有一定增长,但均低于对照,且所有处理植株均未破土,后来全部死亡。(2)所有沙埋处理的叶片可溶性糖含量均显著低于对照,而POD活性显著高于对照,可溶性蛋白质和脯氨酸含量也高于对照。(3)随沙埋深度增加,叶片相对含水量总体呈增加趋势,但大多数处理与对照差异不显著;丙二醛含量基本呈显著下降趋势,可溶性蛋白和脯氨酸含量先增加后下降,而大多数处理的膜透性与对照差异不显著;随着沙埋深度增加,叶片可溶性糖含量显著下降,SOD和POD活性均先增加后下降。(4)相关分析显示,樟子松幼树叶片膜透性变化与MDA含量变化相关性几乎为零,可溶性蛋白与脯氨酸含量呈显著正相关关系,可溶性糖含量与脯氨酸含量呈显著负相关关系。研究表明,沙埋深度低于樟子松株高以上2cm能够促进其幼树生长;沙埋并没有导致樟子松幼树体内的膜脂过氧化,也没有引起细胞膜的损伤,在受到沙埋胁迫时,樟子松幼树体内SOD、POD以及可溶性蛋白和脯氨酸分别在防止其膜脂过氧化和维持细胞膨压中起到重要作用,而可溶性糖含量在沙埋过程中没有起到渗透调节作用。

Effect of Sand Burial on Height Growth of Pinus sylvestris var.mongolica Saplings and Its Physiological Responses

In order to understand effects of sand burial on height growth of Pinus sylvestris var.mongolica saplings and its physiological responses,we investigated the changes in plant height,membrane permeability,osmotic adjustment substances contents,protective enzyme activities of P.sylvestris var.mongolica saplings in different sand burial depths in the Horqin Sand Land of Inner Mongolia in 2013.The results showed that:(1)The sapling could grow normally,plant height and bud length were significant higher when buried depth was lower than 2 cm above saplings height compared to no-buried CK,with a maximum increased magnitude at sand burial depths of 50% of sapling height.When burial depth was higher than 2 cm above sapling height,although the plant height and bud length increased than buried before,they were lower than the CK,and all the buried saplings were not speared out of the earth and then all died.(2)Soluble sugar content was significant lower,POD activity and soluble protein and proline contents were higher at all the burial treatments than that at the CK.(3)With increase of burial depth,RWC(relative water content) tended to increase,but the differences were not significant at all the burial treatments compared to the CK;MDA and soluble sugar contents tended significant decrease,and soluble protein and proline contents and SOD and POD activities increased firstly and decreased later,and membrane permeability had not significant differences at most the burial treatments than that at the CK.(4)The results from correlation analysis showed the correlation between membrane permeability and MDA content was almost zero;proline content had a significant positive correlation with soluble protein content,and soluble sugar content was significantly negatively correlated with proline content.The results suggested that when sand burial depth was lower than 2 cm above sapling height could promote height growth of the saplings,and did not result in membrane lipid peroxidation,also did not cause cell membrane damage.When the sapling subjected sand burial stress,SOD,POD,soluble protein and proline played an important role in preventing the membrane lipid peroxidation and maintaining cell turgor pressure,respectively,while soluble sugar did not play a role in osmotic adjustment.