Asaeda Takashi, Hai Dinh Ngoc, Manatunge Jagath, Williams David, Roberts Jane
Department of Environmental Science and Human Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338, Japan.
Ann Bot. 2005 Aug;96(2):299-312. doi: 10.1093/aob/mci178. Epub 2005 May 31.
The latitudinal differences in the growth characteristics of Typha are largely unknown, although a number of studies have pointed out the effects of climate on the growth and productivity of Typha. Therefore, a dynamic growth model was developed for Typha to examine the effects of latitudinal changes in temperature and radiation on partitioning of the total biomass during the growing season into rhizomes, roots, flowering and vegetative shoots, and inflorescences.
After validating the model with data from growth studies of Typha found in past literature, it was used to investigate the dynamics of above- and below-ground biomasses at three latitudes: 30 degrees, 40 degrees and 50 degrees.
Regardless of the initial rhizome biomass, both above- and below-ground biomass values converged to a latitude-specific equilibrium produced by the balance between the total production and respiration and mortality losses. Above-ground biomass was high from 10 degrees to 35 degrees latitude with sufficient radiation, despite high metabolic losses; however, it decreased markedly at higher latitudes due to a low photosynthetic rate. Below-ground biomass, on the other hand, increased with latitude up to 40 degrees due to decreasing metabolic losses, and then markedly decreased at higher latitudes. Above-ground biomass was enhanced with an increasing number of cohorts regardless of latitude. However, although more cohorts resulted in a larger below-ground biomass at low latitudes, the largest below-ground biomass was provided by a smaller number of cohorts at high latitudes. This difference is due to low production rates of late-season cohorts in high latitudes, compared with consumption for shooting and establishing foliage.
The model could be used to predict the potential growth of Typha in given conditions over a wide range of latitudes and is useful for practical applications such as wetland management or wastewater treatment systems using Typha.
尽管已有多项研究指出气候对香蒲生长和生产力的影响，但香蒲生长特性的纬度差异仍 largely unknown。因此，开发了一个香蒲动态生长模型，以研究温度和辐射的纬度变化对生长季节总生物量在根茎、根、花茎和营养茎以及花序之间分配的影响。
用过去文献中香蒲生长研究的数据验证模型后，将其用于研究三个纬度（30度、40度和50度）地上和地下生物量的动态变化。
无论初始根茎生物量如何，地上和地下生物量值都收敛到由总生产与呼吸及死亡损失之间的平衡所产生的特定纬度平衡状态。在有充足辐射的10度至35度纬度范围内，地上生物量较高，尽管代谢损失较大；然而，在较高纬度由于光合速率较低，其显著下降。另一方面，地下生物量由于代谢损失减少而随纬度增加至40度，然后在更高纬度显著下降。无论纬度如何，地上生物量随着同生群数量的增加而增加。然而，尽管在低纬度更多同生群导致更大的地下生物量，但在高纬度较少数量的同生群提供了最大的地下生物量。这种差异是由于高纬度后期同生群的生产率较低，与用于抽穗和形成叶片的消耗相比。
该模型可用于预测给定条件下香蒲在广泛纬度范围内的潜在生长，对湿地管理或使用香蒲的废水处理系统等实际应用很有用。
