The productive and reproductive biology of flowering plants

Abstract

The seasonal growth cycles and dry matter partitioning of Heloniopsis orientalis (Thunb.) C. Tanaka (Liliaceae) into its component organs throughout the year were studied and compared with one another in five selected populations at different altitudes in Toyama Prefecture, Japan (i.e., 100, 200, 900, 1,900, and 2,600 m above sea level). In addition, reproductive energy allociation (RA) and reproductive capacities of these five populations were critically analyzed in relation to environmental factors of each habitat. As a result, a remarkable cline in the growth cycle, dry matter allocation as well as significant reproductive characteristics including reproductive capacity and allocation was discovered along the environmental gradients (e.g., the length of the growing season) present as a result of different elevations. There is a clear negative correlation between the reproductive capacities and allocations in these five populations (r=0.9236, PH. orientalis allocate increasingly greater energy to reproductive activities in response to the increase in elevation, but, on the contrary, show a marked decreasing tendency in reproductive capacity. Likewise, there is a tendency not only of increased energy allocation to total reproductive structures, but also toward producing a single propagule in successively harsher habitats. Specifically, the RA to total reproductive structures at the fruiting stage incrases from 9.97%, 13.03%, 15.25%, 23.06% to 25.52%, and also the relative amount of the energy invested to producing a single propagule increases from 1.000, 1.298, 2.496, 5.512 to 6.079 in response to an increase in elevation.