沙埋对沙米幼苗生长及生理过程的影响

Effects of sand burial on growth and physiological process of Agriophyllum squarrosum seedlings in Horqin Sand Land of Inner Mongolia,North China

2010—2011年在科尔沁沙地,研究了不同沙埋深度下沙米幼苗生长特性及其逆境生理指标的变化.结果表明:沙米幼苗的耐沙埋能力较强,当埋深超过其株高后生长才会受到严重抑制,而埋深超过其株高1.66倍时仍有部分幼苗存活.当埋深未超过株高时,其幼苗丙二醛含量和膜透性的变化不显著;随着埋深进一步增加,其膜质过氧化加剧,细胞膜受损.沙埋胁迫下,沙米幼苗的超氧化物歧化酶(SOD)、过氧化物酶(POD)活性及脯氨酸含量均显著增加,过氧化氢酶(CAT)活性和可溶性糖含量下降.沙埋使植株光合面积减少、细胞膜受损,导致沙米幼苗死亡率增加、生长受抑,但是SOD和POD活性的增强及脯氨酸含量的增加对于减轻沙埋危害将起到一定的作用.

In 2010-2011, a sand burial experiment was conducted on the Horqin Sand Land of In- ner Mongolia to study the growth characteristics and physiological properties of Agriophyllum squar- rosum seedlings under different depths of sand burial. The A. squarrosum seedlings had stronger tol- erance against sand burial. The seedling growth could be severely inhibited when the burial depth exceeded seedling height, but some seedlings could still be survived when the burial depth exceeded 1.66 times of seedling height. When the burial depth did not exceed the seedling height, the seed- ling MDA content and membrane permeability had no significant change, but the lipid peroxidation was aggravated and the cell membrane was damaged with increasing burial depth. Under sand burial stress, the seedling SOD and POD activities and proline content increased significantly, while the seedling CAT activity and soluble sugar content deceased. Sand burial decreased the leaf photosyn- thetic area and damaged cell membrane, inducing the increase of seedling mortality and the inhibi- tion of seedling growth. The increase of SOD and POD activities and proline content played a deft- nite role in reducing the sand burial damage to A. squarrosum seedlings.