CAJ | 학술논문

研究了两个光照梯度和3个土壤氮素水平交互作用对喜旱莲子草(Alternanthera philoxeroides(Mart.)Griseb.)形态特征和生物量分配的影响.结果表明,全光照促进喜旱莲子草总生物量的积累,但在遮荫条件下,喜旱莲子草可以通过增加株高、光合叶面积和改变生物量分配来适应弱光生境.土壤中氮素含量对喜旱莲子草生长有明显影响,总生物量、株高、叶面积、茎生物量比和叶生物量比等随土壤氮素水平增加而增加.光照和氮素的交互作用对总生物量、根生物量比、茎生物量比和叶生物量比也有显著影响.随着氮素水平的增高.遮荫和高光照处理下喜旱莲子草的叶面积、总生物量和叶生物量比之间的差异减小,而株高和根生物量比之间的差异增大.此外.光照强度对茎生物量比的影响具有明显的氮素浓度依赖性,低氮条件下,茎生物量比在高光照处理下显著高于遮荫处理,而在中氮条件下,遮荫处理却显著高于高光照处理,且在高氮处理下其差异进一步加大.这些结果表明喜早莲子草在高氮素环境下能够通过形态可塑性和生物量分配模式的改变来适应弱光环境所带来的不利影响.研究结果不但可为研究喜旱莲子草对异质生境的入侵机制提供资料,也可为进一步研究喜旱莲子草的入侵和扩散与农业等生态系统中土壤氮素残留的关系提供参考.
연구료량개광조제도화3개토양담소수평교호작용대희한련자초(Alternanthera philoxeroides(Mart.)Griseb.)형태특정화생물량분배적영향.결과표명,전광조촉진희한련자초총생물량적적루,단재차음조건하,희한련자초가이통과증가주고、광합협면적화개변생물량분배래괄응약광생경.토양중담소함량대희한련자초생장유명현영향,총생물량、주고、협면적、경생물량비화협생물량비등수토양담소수평증가이증가.광조화담소적교호작용대총생물량、근생물량비、경생물량비화협생물량비야유현저영향.수착담소수평적증고.차음화고광조처리하희한련자초적협면적、총생물량화협생물량비지간적차이감소,이주고화근생물량비지간적차이증대.차외.광조강도대경생물량비적영향구유명현적담소농도의뢰성,저담조건하,경생물량비재고광조처리하현저고우차음처리,이재중담조건하,차음처리각현저고우고광조처리,차재고담처리하기차이진일보가대.저사결과표명희조련자초재고담소배경하능구통과형태가소성화생물량분배모식적개변래괄응약광배경소대래적불리영향.연구결과불단가위연구희한련자초대이질생경적입침궤제제공자료,야가위진일보연구희한련자초적입침화확산여농업등생태계통중토양담소잔류적관계제공삼고.
Most invasive plants experience highly variable environments during their invasion, spread and establishment,and therefore, it is crucial to understand the factors controlling the success of invasive species. However, few studies have evaluated the interactive effect of both light intensity and soil nitrogen levels on functional response in phenotypic plasticity of invasive plants. The present study examined the main effects of light intensity and soil nitrogen level and their interactions on morphological traits and biomass allocation performance of an alligator weed Alternanthera philoxeroides, a widespread invasive plant in China, by outdoor experiments. Approximately identical size of ramets from one genotype of population were planted separately in plastic pots with combined compost and sand, and grown under the combination of two light intensities (full sunlight and 16.5% of full sunlight) and three soil nitrogen levels (low, midterm and high) treatments. The result indicated that full sunlight enhanced the production accumulation of A.philoxeroides and the plant could allocate more resources to leaf and above-ground stem and less to below-ground root under shade as a response to low light condition. Soil nitrogen level also had a significant effect on plant growth,showing an increase of total biomass, plant height, total leaf area, stem biomass ratio and leaf biomass ratio with the increasing soil nitrogen concentration. Additionally, there was a significant light x nitrogen interaction on total biomass,root biomass ratio, leaf biomass ratio and stem biomass ratio. Differences in leaf area, total biomass and leaf biomass ratio between two light intensities reduced with the increasing soil nitrogen concentration, whereas, those in plant height and leaf biomass ratio showed an opposite trend. In addition, the light effect on stem biomass ratio depended on nitrogen concentration greatly. Under low nitrogen condition, stem biomass ratio was significantly higher in full sunlight treatment compared with that in shade. But it was significantly lower under middle nitrogen condition, and the tendency became even more obvious under high nitrogen condition. Our data further implied that the negative effect caused by shade on plant growth of A. philoxeroides could be altered by phenotypic plasticity in morphology and biomass allocation performance in a response to high nitrogen concentration, which in turn adapts the plant to low light condition. This suggested that the great success of A. philoxeroides over a variety of heterogeneous habitats is probably due to both a high degree of phenotypic plasticity of individuals and compensation of one resource for another. Our study also confirmed the importance of nitrogen in affecting the establishment of invasive A. philoxeroides populations, and therefore,control of A. philoxeroides may be aided by nutrient management.