Competition plays an important role in the replacement of native species by alien plants. A greenhouse experiment was conducted to investigate whether the competition pattern of alien Robinia pseudoacacia L. and native Quercus acutissima Carr. is affected by soil sterilization. Physiological traits, such as gas-exchange parameters and chlorophyll (Chl) content, and growth traits, such as the biomass accumulation of the two species, were examined in natural soil or in soil sterilized with benomyl. The results show that native Q. acutissima inhibits the growth of R. pseudoacacia in natural soil. When the two plants coexisted and competed under sterilization treatment, R. pseudoacacia was less inhibited by Q. acutissima and the competition of R. pseudoacacia decreased the growth of Q. acutissima in terms of biomass, Chl a, Chl b, total Chl, and Chl a/b. These results suggest that soil sterilization benefits the growth of R. pseudoacacia and changes the competition pattern by the changed soil biota. Soil sterilization increased the biomass of root nodules, which ultimately benefits the growth of R. pseudoacacia and root nodule bacteria may be important in the dispersal and invasion process of nitrogen-fixing alien plants such as R. pseudoacacia., H. Chen ... [et al.]., and Obsahuje bibliografii
Changes in chlorophyll (Chl) a+b and a/b, senescence patterns during Chl loss and changes in net photosynthetic rate (P^) of four leaf flushes in Quercus acutissima and Q. serrata were studied. Emergent current-year leaves were classified according to the order of shoot growth flushes (first to fourth flush groups). Senescence patterns showed that leaf fall started from the leaf cohorts of the first flush group (the "oldest" leaf cohorts) which cuhninated upwards to the fourth leaf flush group (the "yoímgest" leaf cohorts). Senescence during Chl loss was accompanied by a decline in Pf^. A strong influence by the leaf flushing phenomenon on senescence was found which limited leaf bearing period and duration of Having large total leaf area and moderately long duration, tiie third and second leaf flush groups reflected the highest photosynthetic potential. This may be a positive attribute since the duration by which these plants maximize the use of its assimilatory organs is an important factor for their carbon fixation.