Pattison R R, Goldstein G, Ares A
Department of Botany, University of Hawaii, 3190 Maile Way, Honolulu, HI 96822, USA, , , , , , US.
Department of Agronomy and Soil Science, University of Hawaii, 1900 East-West Road, Honolulu, HI 96822, USA e-mail:
Oecologia. 1998 Dec;117(4):449-459. doi: 10.1007/s004420050680.
Growth, biomass allocation, and photosynthetic characteristics of seedlings of five invasive non-indigenous and four native species grown under different light regimes were studied to help explain the success of invasive species in Hawaiian rainforests. Plants were grown under three greenhouse light levels representative of those found in the center and edge of gaps and in the understory of Hawaiian rainforests, and under an additional treatment with unaltered shade. Relative growth rates (RGRs) of invasive species grown in sun and partial shade were significantly higher than those for native species, averaging 0.25 and 0.17 g g week, respectively, while native species averaged only 0.09 and 0.06 g g week, respectively. The RGR of invasive species under the shade treatment was 40% higher than that of native species. Leaf area ratios (LARs) of sun and partial-shade-grown invasive and native species were similar but the LAR of invasive species in the shade was, on average, 20% higher than that of native species. There were no differences between invasive and native species in biomass allocation to shoots and roots, or in leaf mass per area across light environments. Light-saturated photosynthetic rates (Pmax) were higher for invasive species than for native species in all light treatments. Pmax of invasive species grown in the sun treatment, for example, ranged from 5.5 to 11.9 μmol m s as compared with 3.0-4.5 μmol m s for native species grown under similar light conditions. The slope of the linear relationship between Pmax and dark respiration was steeper for invasive than for native species, indicating that invasive species assimilate more CO at a lower respiratory cost than native species. These results suggest that the invasive species may have higher growth rates than the native species as a consequence of higher photosynthetic capacities under sun and partial shade, lower dark respiration under all light treatments, and higher LARs when growing under shade conditions. Overall, invasive species appear to be better suited than native species to capturing and utilizing light resources, particularly in high-light environments such as those characterized by relatively high levels of disturbance.
研究了5种入侵非本地物种和4种本地物种的幼苗在不同光照条件下的生长、生物量分配和光合特性，以帮助解释入侵物种在夏威夷雨林中成功的原因。植物在三种温室光照水平下生长，这三种光照水平分别代表了夏威夷雨林林窗中心和边缘以及林下的光照情况，另外还设置了一种未改变遮荫的处理。在全日照和部分遮荫条件下生长的入侵物种的相对生长速率（RGR）显著高于本地物种，平均分别为0.25和0.17克/克/周，而本地物种平均仅为0.09和0.06克/克/周。遮荫处理下入侵物种的RGR比本地物种高40%。全日照和部分遮荫条件下生长的入侵物种和本地物种的叶面积比（LAR）相似，但遮荫条件下入侵物种的LAR平均比本地物种高20%。在不同光照环境下，入侵物种和本地物种在地上部和根部的生物量分配以及单位面积叶质量方面没有差异。在所有光照处理中，入侵物种的光饱和光合速率（Pmax）均高于本地物种。例如，在全日照处理下生长的入侵物种的Pmax范围为5.5至11.9微摩尔/平方米/秒，而在类似光照条件下生长的本地物种的Pmax为3.0 - 4.5微摩尔/平方米/秒。入侵物种的Pmax与暗呼吸之间线性关系曲线的斜率比本地物种更陡，这表明入侵物种在较低呼吸成本下比本地物种能同化更多的CO₂。这些结果表明，入侵物种可能比本地物种具有更高的生长速率，这是由于在全日照和部分遮荫条件下具有更高的光合能力；在所有光照处理下具有更低的暗呼吸；以及在遮荫条件下生长时具有更高的LAR。总体而言，入侵物种似乎比本地物种更适合捕获和利用光照资源，特别是在高光环境中，如那些以相对较高干扰水平为特征的环境。
