Community assembly mechanisms and succession processes significantly differ among treatments during the restoration of Stipa grandis - Leymus chinensis communities.

Understanding community assembly mechanisms is helpful to predict community dynamics. To explore which community assembly mechanism(s) drive(s) the grassland restoration in semi-arid region, we investigated the relationships between plant trait and species relative abundance (SRA), and estimated community functional diversity indices for each community under different treatments (enclosure, grazing and mowing treatment) in a restoration region of Stipa grandis - Leymus chinensis communities in the northern China from 2010 to 2012. There was a high fraction of significant relationships between trait value and SRA, suggesting that niche theory structured the grassland restoration in this region.

Litter species diversity is more important than genotypic diversity of dominant grass species Stipa grandis in influencing litter decomposition in a bare field.

Studies have indicated that plant litter diversity can affect litter decomposition at both species diversity and genotypic diversity level within a species. However, the essence and relative importance of these two diversity levels on litter decomposition remain unknown. Here, two independent one-factor experiments, litter species diversity and litter genotypic diversity of the dominant species-Stipa grandis, were carried out to explore the effects of initial litter quality, litter composition and diversity on decomposition of mass, nitrogen (N), carbon (C) and phosphorus (P) simultaneously.

Phenotypic plasticity vs. local adaptation in quantitative traits differences of Stipa grandis in semi-arid steppe, China.

Whether plants are able to adapt to environmental changes depends on their genetic characteristics and phenotypic plastic responses. We investigated the phenotypic responses of 7 populations of an important dominant species in semi-arid steppe of China - Stipa grandis, and then distinguished which adaptive mechanism(s), phenotypic plasticity or local adaptation, was/were involved in this species to adapt to environmental changes. (1) All traits were significantly influenced by the interaction of population and growth condition and by population in each condition, and inter-population variability (CV) was larger in the field than in the common garden for 8/9 traits, indicating that both phenotypic plasticity and genetic differentiation controlled the phenotypic differences of S.

Influence of nitrogen fertilizer and endophyte infection on ecophysiological parameters and mineral element content of perennial ryegrass.

An experiment was designed to determine the effect of the fungal endophyte Neotyphodium lolii on the growth, physiological parameters and mineral element content of perennial ryegrass (Lolium perennel L.), when growing at two N supply levels. Endophyte infection had a significant positive effect on both shoot and root growth of ryegrass, but this difference was only significant in the high N supply treatment.

Genetic diversity and population differentiation of the dominant species Stipa krylovii in the Inner Mongolia Steppe.

Random amplified polymorphic DNA was used to assess the level of genetic diversity and genetic structure of Stipa krylovii (Gramineae), an important dominant species in the northern grasslands of China. Genetic diversity was low within S. krylovii populations, and diversity at the population level was associated with precipitation and cumulative temperature variations.

[Cellar senescence and tumor].

Cells withdrawing from the cell cycle and entering the terminally non-dividing state are referred senescence. With few exceptions,normal cells necessarily enter this process. Molecular analyses have identified some changes in gene expressions as cells become senescent, including repression of positive-acting transcriptional regulators, over-expression of CDK inhibitor, and interference with downstream pathways, and changes in telomere and telomerase.