二次遷移初期優占種の生態 : シロザについて

抄録

The life history of Chenopodium album, a dominant of the pioneer stage of secondary succession in Central Japan is discussed in relation to the causes of succession. In this paper, the type of life history is defined by the use of the particular combination of ecological characteristics, including seed weight, germination behaviour, weight ratio of top and root (T/R ratio), stem weight/leaf weight ratio (Ws/Wl ratio), seed production, etc. The T/R ratio of plants grown in pots and those collected from a field was constant at 4.9,irrespective of the increase of the plant weight. During the growth of the plant the Ws/Wl ratio increased according to the relationship of Ws/Wl=0.773T^<0.249>. The relationship between the number of seed (Sn) and diameter at stem base of plants (D cm) was Sn=3.71×10^4 D^<2.52>. The weight of the whole plant (Wg) is a function of the diameter of stem (D cm) according to the equation W=24.8D^<2.76>. Based on the latter two equations, the ratio of seed weight (Sw g) produced by a plant to whole plant weight (Wg) is given by Sw/W=0.473W^<-0.060>, which suggests that about 47% of the plant weight is allocated to the seeds, if -0.060 is regarded nearly equal to zero.