| Ecological invasion is one of the most popular ccological focuses around the world. People pays more attention to ecological calamities caused by introduce than cvcr. But at present. a thorough understanding has not been made clear about the ecological iucchanism of explosive population growing in new flora. A nonindigenous species in China, 0. coryrnhoxa, is the object of study. In this paper, thc following rcspccts arc studied. (I) Dynamics of natural population are investigated. In the light of observation on population dynani cs and rcproduction allocation in different habitats, a prcl i mi nary comprehension is acquired about its ecological characteristics and adaptation strategies. (2) The mechanism of population adaptation to environment is studies. A lifetime experiment is designed to test the reaction of cultivated populations to different treatments. The characteristics of morphological plasticity, growth strategies and life history strategies are gcncralizcd. (3) The population regulation mechanism is studied. Dcnsity regulation reflects on characteristics of morphology, dynamics and production. The results show as follows. Bascd on the investigation on population dynamics and reproduction features, six results are .obtamncd. (1) Mortality rate is positively related to densities, that is, higher density incline to higher mortality rate. During the growth period, there arc thrcc peaks in mortality rate of all the population. (2) There is trado-offs between seasonal changes of leaves population and that of little bulbs remained in the soil. (3) The dynamics of biomass structure and leaf area arc highly integrated with their habitats. The increasing rate and timing of biomss indexes and leaf area index are varied with habitats. So do the biomass allocation between photosynthetic and nonphotosynthetic organs. (4) Little bulb in the soil is dormancy mass as well as vegetative propagator, which help to resist tmnfavorablc conditions. The vegetative daughters disperse through soil removal and is strongly resistant to disturbance caused by human beings. (5) The reproduction strategies change with light gradients. With light intensity increasing, bionmass allotted to vegetative propagation increase while that allotted to sexual reproduction decrease. (6) Correlation analysis shows that sexualreproduction allocation is positively re1ated to A/U, leaveS biolnass allocation ratio. flowcrbiomass and 1eaves bio[llass, whiIc nqativcly rclated to blllbs biomass aIlocatiol1 ratio.Thc population adaptation of O. co)mp1bo.va to di(ferellt cllvirol1mental co11ditiol1s sl1otvsin three respects, morphological plasticity, gro'vth and lifo history. (l ) Co1nparcd with CK,individuals under water stress are in smaller siFe. Leaves are witll shortor petiole. smallerleD f arca, s11orter Iifc span and higher turnover rate. Biomass pre ramet Dnd accul1lulatedmodular biomass decreaso whilc A/U remainc4 fixed. Shadow helps to dccrease lcaf turnoverratO alld incrcase leaf ftlnctiol1' timing. Accul11uIated bio1nasS 'of lear is sin1i1ar to tl1at undcrwater stress. lndividuals u1lder conlpetition i11cliJ1ed to be large, TOtaI bion1ass pre rnl1let andbulbs biomass proportion i11crcase sig11ificaIlt1y. (2) Asynchronous growtl1 of 111odu1cs lllain1yrcflects oll the timing and speed of growtl1. l11dividuals ulldcr water strcss grow slow 'andslnall. Growth period is sl1ort either under water strcss or under shadows. But u11der shadow,the 1eaf area grows fast, wl1ile height grows slow COInpetition enI1al1ccs l11odular growtl1,both ill the timing and spccd, (3) Relations among populatiol1 sllrvival, growtl1 andreprodtlctiol1 change due to the restriction of available resourccs. Ul1dcl' t"atcr stress,population grow... |
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