Hedysarum laeve Maxim. (Leguminosae) is one of the major species used frequently in revegetation of dune_field in the sandlands of the northern part of China by means of aerial sowing. Seedlings of the species after e...Hedysarum laeve Maxim. (Leguminosae) is one of the major species used frequently in revegetation of dune_field in the sandlands of the northern part of China by means of aerial sowing. Seedlings of the species after emergence above the sand surface may be buried in sand to various depths during its establishment in late spring and early summer. A study was made to examine the effects of sand burial at different levels of 0 (control), 33%, 67%, 100% and 133% of their shoot height, on the survivorship, growth, and biomass allocation pattern of H. laeve seedlings (one and two weeks old after emergence). When burial depth was up to 100% of their shoot height, about 70% seedlings died; and the burial at depth of 133% of their shoot height led to death of all seedlings. When seedlings was buried at depth of 33% and 67% of their shoot height, respectively, after six_week growth, their biomass of whole plant, blade, and root and relative growth rate were higher than the unburied counterparts. The seedlings in both 33% and 67% sand burial treatments did not significantly change their biomass allocation pattern comparing with the unburied ones. Furthermore, the number of leaves and shoot height of the seedlings in both 33% and 67% sand burial treatments were not significantly different from those of unburied individuals, respectively. The newly born leaves of the surviving seedlings, in 33%, 67%, and 100% burial treatments, during the period of experiment, were significantly more than those in control.展开更多
Calamagrostis epigejos (L.) Roth. is a perennial grass with slender and long rhizome segments between interconnected neighbor ramets. To investigate the phenotypic plasticity in response to the heterogeneous soil wate...Calamagrostis epigejos (L.) Roth. is a perennial grass with slender and long rhizome segments between interconnected neighbor ramets. To investigate the phenotypic plasticity in response to the heterogeneous soil water supply, ramet pairs of the species were subjected to heterogeneous water supply by which either mother ramets or daughter ramets were in high or low soil water supply, respectively, in the Maowusu (Mu Us) Sandy Land of Nei Mongol. The results showed that the phenotypic characteristics of the individual ramets of C epigejos were greatly influenced by the heterogeneous water supply. The ramets treated with high water supply significantly produced more new rhizomes and more offspring (ramets), and accumulated more shoot biomass, and allocated more biomass to their shoots than those treated with low water supply. In comparison with the daughter ramets in homogeneous soil water supply, phenotypic characteristics, in terms of new rhizome growth, the production of new offspring, and the biomass allocation pattern, of the daughter ramets within the pairs of the species were not significantly changed, no matter that high or low soil water supply to mother ramets. The phenotypic responses of mother ramets to soil water supply were similar to those of daughter ramets. From these results, it is inferred that the interconnected ramets of C epigejos response phenotypically to their local soil water rather than to the soil water experienced by the interconnected ramets. The interconnected ramets of C epigejos might be independent of each other in water relationship, although they are physically interconnected with rhizome segments. The physiological independence of interconnected ramets might facilitate the risk spreading and thus enhance the genet survivorship under the frequent drought stresses in Mu Us Sandland.展开更多
应用中尺度区域模式RAMS(the regional atmospheric model system),在40余组不同参数的条件下模拟中国干旱半干旱黑河地区的地表能量通量和土壤温度特征,并以此探索模式在干旱半干旱地区的适用性。为了证明模拟结果的准确性和模式的稳定...应用中尺度区域模式RAMS(the regional atmospheric model system),在40余组不同参数的条件下模拟中国干旱半干旱黑河地区的地表能量通量和土壤温度特征,并以此探索模式在干旱半干旱地区的适用性。为了证明模拟结果的准确性和模式的稳定性,模拟连续运行30天,其中包含晴好和阴雨的天气过程。模拟结果表明:即使使用较为可靠的NECP再分析气压层资料和实地探测资料,进行初始场和参数的输入,RAMS的默认设置也很难较为合理地反演出地表能量通量,只有合理地调整好其土壤特征参数,RAMS才能得到与实测资料符合得较好的结果。土壤特征参数对模拟结果影响较大,影响因子的重要性依次为:土壤含水量、土壤层总厚度、土壤温度。展开更多
文摘Hedysarum laeve Maxim. (Leguminosae) is one of the major species used frequently in revegetation of dune_field in the sandlands of the northern part of China by means of aerial sowing. Seedlings of the species after emergence above the sand surface may be buried in sand to various depths during its establishment in late spring and early summer. A study was made to examine the effects of sand burial at different levels of 0 (control), 33%, 67%, 100% and 133% of their shoot height, on the survivorship, growth, and biomass allocation pattern of H. laeve seedlings (one and two weeks old after emergence). When burial depth was up to 100% of their shoot height, about 70% seedlings died; and the burial at depth of 133% of their shoot height led to death of all seedlings. When seedlings was buried at depth of 33% and 67% of their shoot height, respectively, after six_week growth, their biomass of whole plant, blade, and root and relative growth rate were higher than the unburied counterparts. The seedlings in both 33% and 67% sand burial treatments did not significantly change their biomass allocation pattern comparing with the unburied ones. Furthermore, the number of leaves and shoot height of the seedlings in both 33% and 67% sand burial treatments were not significantly different from those of unburied individuals, respectively. The newly born leaves of the surviving seedlings, in 33%, 67%, and 100% burial treatments, during the period of experiment, were significantly more than those in control.
文摘Calamagrostis epigejos (L.) Roth. is a perennial grass with slender and long rhizome segments between interconnected neighbor ramets. To investigate the phenotypic plasticity in response to the heterogeneous soil water supply, ramet pairs of the species were subjected to heterogeneous water supply by which either mother ramets or daughter ramets were in high or low soil water supply, respectively, in the Maowusu (Mu Us) Sandy Land of Nei Mongol. The results showed that the phenotypic characteristics of the individual ramets of C epigejos were greatly influenced by the heterogeneous water supply. The ramets treated with high water supply significantly produced more new rhizomes and more offspring (ramets), and accumulated more shoot biomass, and allocated more biomass to their shoots than those treated with low water supply. In comparison with the daughter ramets in homogeneous soil water supply, phenotypic characteristics, in terms of new rhizome growth, the production of new offspring, and the biomass allocation pattern, of the daughter ramets within the pairs of the species were not significantly changed, no matter that high or low soil water supply to mother ramets. The phenotypic responses of mother ramets to soil water supply were similar to those of daughter ramets. From these results, it is inferred that the interconnected ramets of C epigejos response phenotypically to their local soil water rather than to the soil water experienced by the interconnected ramets. The interconnected ramets of C epigejos might be independent of each other in water relationship, although they are physically interconnected with rhizome segments. The physiological independence of interconnected ramets might facilitate the risk spreading and thus enhance the genet survivorship under the frequent drought stresses in Mu Us Sandland.
文摘应用中尺度区域模式RAMS(the regional atmospheric model system),在40余组不同参数的条件下模拟中国干旱半干旱黑河地区的地表能量通量和土壤温度特征,并以此探索模式在干旱半干旱地区的适用性。为了证明模拟结果的准确性和模式的稳定性,模拟连续运行30天,其中包含晴好和阴雨的天气过程。模拟结果表明:即使使用较为可靠的NECP再分析气压层资料和实地探测资料,进行初始场和参数的输入,RAMS的默认设置也很难较为合理地反演出地表能量通量,只有合理地调整好其土壤特征参数,RAMS才能得到与实测资料符合得较好的结果。土壤特征参数对模拟结果影响较大,影响因子的重要性依次为:土壤含水量、土壤层总厚度、土壤温度。
