草原沙漠化过程中土壤因素分析及其植物的生理响应

基于2001～2003年内蒙古锡林郭勒盟多伦县草原沙漠化过程中土壤因子（5个指标）与不同耐胁迫类型植物的生理响应（7个指标）的相关分析，得到的结果是：①羊草（敏感型）各生理指标与土壤含水量及土壤C／N比的相关水平较高（P〈0．01），其中以MDA和ABA与土壤因子的相关性较高（P〈0．01）。②糙隐子草和冷蒿（积极忍耐型）MDA只与土壤C／N比关系均极显著相关（P〈0．01）．同时ABA与反映土壤的5个指标的关系亦极显著相关（P〈0．01）。③扁蓿豆（迟钝型）对土壤物理性质的敏感性要高于土壤的化学性质，土壤营养元素的衰减并没有成为制约其生长发育的主导因子。另外在扁蓿豆的7个生理指标中MDA与土壤的相关性最高（P〈0．01），而ABA与土壤因子均不相关（P〉0。05）。④综合植物生理指标与土壤因子的相关分析，多数植物的MDA和ABA在沙漠化胁迫环境下反应较强。⑤不同类型植物在沙漠化过程中对土壤因子的响应机制不同，其中敏感型对土壤水分、C／N比响应较强，而积极忍耐型对土壤反应的主导因素不突出，总体上土壤因子中C／N比与植物的生理响应关系密切。

Analysis on the soil factor and physiological response of the plants in the process of sandy desertification on grassland

The aim was to find the most practical measure to father desertification on grassland. Three-year research was carried out from 2001 to 2003 in Duolun County, Xilin Gol, Inner Mongolia, China. A series of degradation gradients or stages were established by clustering analysis, and corresponded to 5 community types. Five community types were selected as the sampling sites. Four common plant populations (i.e., Leymus chinensis, Cleistogenes squarrosa, Artemisia frigida and Melilotoides ruthenica) were chosen because of their different physiological responses to sandy desertification. The correlation analysis was made between the soil factor (5 soil indices) and the physiological response of per plant population (7 physiological indices). The results showed that in the course of the sandy desertification on grassland, the physiological response of L. chinensis, an impressible type, had more significant correlations with the soil moisture and C/N in the soil than others (P < 0.01) relatively. The soil moisture and C/N in the soil are likely the key factors for the damage on a physiological level. Its malondialdehyde (MDA) and abscisic acid (ABA) had more significant correlations than others with 5 soil indices as a whole (P < 0.01). C. squarrosa and A. frigida are of resistant types. Only the correlations of C/N among 5 soil indices with both MDAs were consistent and very significant (P < 0.01). Both ABA relations to 5 soil indices were consistent, and, similarly, were very significant (P < 0.01). M. ruthenica, a retarded type, was more sensitive to soil physical character (the soil moisture and the content of clay) than soil chemical character (the content of C, the total N and C/N in the soil), suggesting that the degradation of nutritious elements in the soil is not the leading factor in holding back its growth. Its MDA showed a more significant correlation (P < 0.01) than others as a whole, but its ABA did not show a significant correlation with each of the soil indices (P > 0.05). The synthesis result showed that MDA and ABA in the plants responded intensively to desertification stress. For each of the stress resistant types, there were different soil response mechanisms under different stages. The impressible type responded intensively to the soil moisture and C/N. The response of the resistant type to the soil factor did not appear to be a dominant factor. Altogether, the physiological response of plants mostly had a significant correlation with the C/N in the soil.