種子重を異にするイネ科牧草種子の発芽にともなう貯蔵養分消費と乾物重増加

抄録

To clarify the influence of seed weight on the early vegetative growth of seedlings in several grasses and what extent the difference of early growth can be explained by difference in seed weight especially when two or three species of grasses are in mixed culture where those are mutually, different mean seed weight, decrease in seed reserve substances followed by the germination and dry matter increase in seedling were examined for 9 grass species 15 varieties. Results obtained are as follows: 1) Comparing two varieties belong to the same species, heavy seed weight variety which has much seed reserve substances consumes them more rapidly than light seed weight variety. Dry matter increase in the former seedling is, therefore, quantitatively much more than in the latter. The relative growth rate (RGR) of dry weight of light seed weight variety is, conversely, higher than that of heavy seed weight variety. Consequently, it is suggested that variety which has originally light seed weight has possibility to restore its inferiority in seedling growth immediately after it takes to germinate because the RGR of young seedling of light seed weight variety is higher than that of heavy seed weight variety. About a month after germination, however, the difference of RGR between varieties become to disappear and thereafter the RGR's of both variety become to same value in their time course. It is fact that the initial seed weight affects positively the vegetative growth of grasses over a conciderably long period. 2) Among species which have originally different seed weight, on the contrary, the difference of seedling vigor (dry matter increase) between species does not necessarily be ascribed to the difference in their seed weight.