Carbohydrate and Lipid Contents of Celmisia Plants in Alpine Snowbank and Herbfield Communities on Rock and Pillar Range, New Zealand

Carbohydrate and lipid cycles in relation to plant phenology were examined in alpine snowbank and herbfield populations of Celmisia haastii var. tomentosa, C. prorepens and C. viscosa on Rock and Pillar Range, New Zealand. Major periods of carbohydrate build-up and depletion were observed in roots, stems and evergreen leaves during the growing season. Depletion generally occurred during flowering scape elongation, flowering, a late February-early March burst of vegetative growth and overwintering. Although carbohydrates accumulated in some tissues to near seasonal maxima at the onset of winter snow cover, they dropped during the winter to near seasonal minima. Thus, the species do not retain large amounts of carbohydrate reserves over winter, and major periods of growth and flowering are not sustained by carbohydrate reserves from previous growing seasons. Lipid levels in the evergreen leaves were remarkably high. Maximal observed percentages were 6.6, 14.6 and 20.3% in the three species, respectively. Lipid percentages decreased during flowering scape elongation-early flowering in C. viscosa, and possibly during flowering and the February-March growth period in C. haastii. Lipid percentages increased markedly during the winter in C. prorepens. The evergreen leaves may serve as overwinter storage sites for lipids in C. prorepens and C. viscosa. INTRODUCTION Arctic and alpine environments of the Northern Hemisphere have short, cool growing seasons of only a few weeks duration (Bliss, 1956). Plants adapted to these environments must complete their vegetative growth and set seed during these few weeks of favorable weather. Consequently, spring bursts of rapid vegetative growth and flowering characterize most tundra species. This rapid growth must depend on translocation and utilization of stored reserves from the previous growing season as well as current photosynthate (Fonda and Bliss, 1966; Mooney and Billings, 1960, 1961; Russell, 1940, 1948). In perennial species, the depleted reserves must be replenished later in the growing season for use the following year. These reserves are usually stored as carbohydrates in stems and roots, although lipids may also be important reserves in old leaves and stems of evergreen alpine species (Bliss and Mark, 1965; Hadley and Bliss, 1964). In contrast, New Zealand alpine environments have long growing seasons which often exceed 5 months; however, temperatures are favorable for plant growth for only short periods throughout those prolonged seasons (Bliss 1969; Mark,. 1965; Mark and Bliss, 1970). Consequently, vegetative growth is slow and intermittent over 2-4 months (Bliss, 1969). The objective of the present study is to examine energy reserves in