Department of Biological Sciences, Binghamton University, Binghamton, New York 13902 USA.
Am J Bot. 2001 Aug;88(8):1469-78.
We transplanted Nuphar variegata with submersed leaves only into natural lake sediments in pH-, [CO(2)]-, depth-, and temperature-controlled greenhouse tanks to test the hypotheses that more fertile sediment, lower free [CO(2)], and shallower depth would all stimulate the development of floating leaves. Sediment higher in porewater [NH(4)(+)] favored floating leaf development. Low CO(2)-grown plants initiated floating leaf development significantly earlier than high CO(2)-grown plants, which produced significantly more submersed leaves and fewer floating leaves. Mean floating leaf biomass was significantly greater than mean submersed leaf biomass but was not influenced by CO(2) enrichment, whereas mean submersed leaf biomass increased 88% at high [CO(2)]. At the shallower depth (35 cm), floating leaves required 50% less biomass investment per leaf than at 70 cm, and a significantly greater proportion of plants had floating leaves (70 vs. 23-43% at 35 vs. 70 cm, respectively) for the last three of the eight leaf censuses. Sediment type, water depth, and especially free [CO(2)] all can influence leaf morphogenesis in Nuphar variegata, and the development of more and larger submersed leaves with CO(2) enrichment favors the exploitation of high [CO(2)] when it is present in the water column.
我们仅将具有沉水叶的荇菜移植到 pH 值、[CO2]、深度和温度控制的温室水箱中的天然湖底沉积物中，以检验以下假设：更肥沃的沉积物、更低的游离[CO2]和更浅的深度都会刺激浮叶的发育。底泥中具有较高的孔水[NH4 (+)]有利于浮叶的发育。在低 CO2 条件下生长的植物比在高 CO2 条件下生长的植物更早地开始浮叶发育，后者产生的沉水叶更多，浮叶更少。平均浮叶生物量显著大于平均沉水叶生物量，但不受 CO2 富集的影响，而平均沉水叶生物量在高 CO2 下增加了 88%。在较浅的深度（35 厘米），每片浮叶的生物量投资比在 70 厘米时少 50%，在最后三次叶片普查中，有更多的植物（分别为 70%和 23-43%）具有浮叶（70 厘米与 35 厘米相比）。沉积物类型、水深，尤其是游离[CO2]都可以影响荇菜的叶片形态发生，并且随着 CO2 的增加，更多和更大的沉水叶的发育有利于在水柱中存在高 CO2 时的开发。
