Ecophysiology of the Sand Sedge, Carex Arenaria L. I. Growth and Dry Matter Distribution

Abstract

The growth and the dry matter distribution of sand sedge plants were followed in time by means of an indirect estimation method. This method enabled us to calculate the time courses of both the growth of the whole plant, and the growth of the individual shoots from measure: ments of the shoot length, the number ofleaves and the length and width of the leaflaminae only.The growth rate of each individual shoot decreases with time. In the primary shoots 1-7 the amounts of dry weight added during the experiment were equal to each other, indicating a higher growth rate for the younger shoots. A comparison of dry weight production and increase in dry weight of shoots gave the amount of dry matter import or export by those shoots. The dry matter production in the tip part of the rhizome (two shoots, a shoot bud, the rhizome parts and the roots attached to them) proved to be far too small to maintain the growth of the non-assimilating tissue in this part. There must be a considerable export from the older plant part towards the rhizome tip region. It should be mentioned that the results presented here are similar to those obtained from 14C studies. Because of its simplicity the method we used would be very suitable for use in field studies.

ECOPHYSIOLOGY OF THE SAND SEDGE CAREX ARENARIA L. II. THE DISTRIBUTION OF14C ASSIMILATES

“…3, line b, c and d). The results obtained for the latter are in good accordance with each other and with those obtained earlier using a different method (TIETEMA & VROMAN 1978). In general we can conclude that under the growth conditions given, a particular shoot starts its export with a low export percentage that will increase during its lifetime and will finally reach an average level of ± 33% of its own assimilation.…”

“…4b). This decreasing assimilate export by the younger shoots will, at least partly, be accountable for the increasing growth rate reported for those shoots in plant systems of increasing size (TIETEMA & VROMAN 1978).…”

“…1) consisted of the apical part (1-5 shoots) of a rhizome system. Contrary to the former paper (TIETEMA & VROMAN 1978) now the youngest shoot was given number I, the second youngest shoot number II etc., the highest figure always indicating the oldest shoot of the system. The entire part of the rhizome in front of shoot I is referred to as the rhizome tip.…”

“…In a previous paper (TIETEMA & VROMAN 1978) the time course of the growth of both the individual shoots and the sand sedge plant as a whole, as measured by an indirect method, has been described. It appeared that all assimilating shoots exported dry matter, with the exception of the youngest.…”

Growth, reproduction, and production biology of mouse-ear and king devil hawkweed in eastern South Island, New Zealand

“…The maximum live biomass 69 was assumed to have occurred at the peak of seed production (see Tietema & Vroman 1978). The maximum living biomass was derived from the growth curve as the sum of the leaves remaining (non-reproductive plants weight), inflorescences and scapes, and the stolons.…”