Growth and nonstructural carbohydrate reserves inChionochloa rigidaandC. macra,and their short-term response to fire

Abstract

The relationships of growth and flowering to storage of nonstructural carbohydrate reserves and the influence of the pastoral management practice of burning on these relationships have been investigated in Cizionoclzioa rigida and C. macra on the Old Man Range, Central Otago.Growth, as measured by elongation of the youngest exposed leaf, decreased significantly with increasing altitude. It was significantly greater in C. rigida than in C. macra. Leaf dieback did not show a significant species difference, but decreased significantly with increasing altitude in C. macra. Neither new leaf nor new tiller production was significantly affected by species. The production of new tillers did, however, decrease significantly with increasing altitude in C. macra.Spring burning increased leaf elongation, relative to unburnt plants during the first two seasons after fire, C. rigida > C. macra. Leaf die back exceeded that of unburnt plants during the season after a spring burn, but was depressed next season. Sucrose is the major component of the non structural carbohydrate reserves in both species, occurring with small amounts of starch, glucose, and fructose. Reserve carbohydrates are stored in both leaf and stem tissue. Roots were consistently low in nonstructural carbohydrates. Carbohydrate reserves were lowest during the period of active growth, increasing towards the end of the growing season. Reserve carbohydrate storage (expressed as a percentage of plant dry weight) increased with altitude, with C. macra > C. rigida .. Fire, which stimulated growth, reduced carbohydrate reserves to low levels, especially dunng the season of burning. Carbohydrate reserve levels were approaching those of adjacent unburnt plants by the end of the first season after fire. 435

Snow Tussocks, Chaos, and the Evolution of Mast Seeding

“…As well as flowering following warm summers, some Chionochloa species also flower heavily after being burned in wildfires (Payton and Brasch 1978;Payton and Mark 1979) despite having reduced carbohydrate levels at that time. Payton and Mark (1979) showed that in C. rigida, plants invariably flowered heavily in the year after fire, and it then took 14 yr of reduced growth and flowering for biomass levels to recover to prefire levels.…”

“…This new tiller is not competent to flower for perhaps 3-5 yr depending on resource levels, but even in the heaviest flowering years only a small percentage of tillers (!20%) are consumed by flowering, so a shortage of competent tillers should not limit flowering. However, heavy flowering years do deplete the plant's stores of nonstructural carbohydrates (Payton and Brasch 1978).…”

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

“…on New Zealand species with succe .. (e.a., Scott 1961Scott , 1977aMark 1969;Payton &. Brasch 1978).…”

Nutrient concentrations in narrow-leaved snow tussock (Chionochloa rigida) after spring burning

“…Methods used to collect and prepare samples for nutrient analyses are described in Payton & Brasch (1978). Plant material was stripped of all dead material and separated into leaf* and stem.…”

“…Payton & Brasch (1978) and Payton & Mark (1979) examined the short and longer term effects of spring burning on growth, flowering, and nonstructural carbohydrate reserves in snow tussocks. This paper integrates that work with an examination of the effects of fire on nutrient concentrations in Chionochloa rigida.…”