The Control of Population Growth Is the Function of the Central Government

Mr.Jiang Zcmin,Gencral-Seerctary of the Cen-tral Committee of the Chincse Communist Party and.Chairman of the People's Republic of China,in a rC-ccnt spcech cm phasized that the family planning pro-gramme should be strictly and effectively im plemented in 1994,a year of crucial importance for promoting re-form and opening and thc drive lowards.modernization.To makc continucd contributions to the sociocconomic development in the country,we must fulfil the plan for controlling population growth..The spcech was delivcred at the anua!National Fo-rum on Family Planning Work convened jointly by the Party's Central Committcc and the Statc Council.

Elevated nitrogen and co-evolution history with competitors shape the invasion process of Galinsoga quadriradiata

Invasive plants usually experience population differentiation as they expand from their initial invasive range to the edge.Moreover,invasive plants usually encounter competitors which shared different co-evolutionary histories with them.These factors may lead to varying responses of invasive plant populations to elevated nitrogen deposition during expansion.However,this issue has received limited attention in prior research.To address these challenges,we conducted a greenhouse experiment to investigate how population differentiation of Galinsoga quadriradiata interacts with the presence of various competitors in response to increased nitrogen deposition.Competitor types(new or old that shared short or long co-evolutionary history with the invader,respectively)were set to compete with the invasive central and edge populations under different nitrogen addition treatments.Individuals from the central population of G.quadriradiata,originating from the initial invasion range,showed greater total mass,reproduction and interspecific competitiveness compared with the edge population.Nitrogen addition improved growth and reproductive performance in both populations,and the central population had a stronger response compared with the edge population.The performance of G.quadriradiata was inhibited more effectively by old competitors than new competitors.Our results indicate that population differentiation occurs in terms of growth and competitiveness during the range expansion of G.quadriradiata,with the central population exhibiting superior performance.Co-evolutionary history with competitors is considered unfavorable for invasive plants in this study.Our results highlight the combined effects of population differentiation in invasive species and their co-evolution history with competitors in the context of global change factors.