In invasion ecology, hypothesis of an invasive species exhibiting enhanced performance in the introduced range has been widely acknowledged. Examining the role of phenotypic plasticity in improving plants’ performance is essential to understand adaptive responses of an exotic invasive species to environmental variations. As Parthenium hysterophorus L. (Asteraceae) is one of the most widespread subtropical invader globally, we selected it as a model plant for studying its adaptive responses along the elevation gradient. Sites at an elevation of 700 m, 900 m, 1100 m and 1500 m were selected in the lower Himalayas for analysing plant functional traits of the weed and assessing variations in biomass allocation along elevation. Non-reproductive traits, i.e. above-ground plant height (AGPH) and below-ground biomass (BGB), and reproductive traits, i.e. capitula count per plant (CC), seed size, seed thickness and seed mass varied significantly with the elevational gradient. Soil properties also exhibited significant variations along elevation, except pH and total nitrogen (TN). Production of large number of heavier seeds, with smaller size at higher elevations showed enhanced reproductive fitness (adaptation) of P. hysterophorus. The study concluded that alteration in reproductive traits aids the successful invasion and expansion of P. hysterophorus in mountain ecosystems.

在入侵生态学中，关于入侵物种在所介绍范围内表现出增强性能的假设已得到广泛认可。研究表型可塑性在改善植物性能中的作用对于理解外来入侵物种对环境变化的适应性反应至关重要。由于银胶菊L.（菊科）是全球最广泛的亚热带入侵者之一，我们选择它作为模型植物来研究其在海拔梯度上的适应性响应。在喜马拉雅山的下部，选择海拔700 m，900 m，1100 m和1500 m的地点，以分析杂草的植物功能性状并评估海拔上生物量分配的变化。非生殖性状，即地上植物高度（AGPH）和地下生物量（BGB），以及生殖性状，即每株植物的头盖数量（CC），种子大小，种子厚度和种子质量随海拔梯度而显着变化。除pH和总氮（TN）外，土壤特性还随高度变化。生产大量较重的种子，P. hysterophorus。研究得出结论，生殖性状的改变有助于山区生态系统对P. hysterophorus的成功入侵和扩展。