David H. Firmage

Pollen viability and longevity: practical, ecological and evolutionary implications.

The present article reviews the various definitions and terminology of pollen viability and longevity as well as the various tests of its assessment. We compare the advantages and the disadvantages of each method and suggest some practical implications as revealed by the extensive data. We recognize eight main hypotheses concerning the ecology and the evolution of pollen longevity and critically evaluated them according to the literature. The hypotheses are grouped as follows: (1) Desiccation risk-carbohydrate content; (2) Pollen packaging; (3) Pollen competitive ability; (4) Pollinator activity-stigma receptivity duration; (5) Self-pollination chance; (6) Pollen exposure schedule; (7) Pollen travel distance, and (8) Pollen removal chance.

Environmental influences on the monoterpene variation in Hedeoma drummondii

Abstract Samples of leaves were taken from clonal stock of Hedeoma drummondii to determine the effect of light and temperature variations on the monoterpenes. Low light intensity and cold conditions caused significant differences in quantitative levels of some of the major monoterpene constituents, as well as total yield. The changes are discussed in relation to photosynthate availability and implications for taxonomy.

Effect of development on monoterpene composition of Hedeoma drummondii

Abstract Samples of leaves, flowers and whole plants were taken from clonal stock of Hedeoma drummondii to determine the effect of developmental age on the monoterpene profile. GLC analysis revealed that there are significant differences in the quantity of major monoterpenes in leaves and flowers of different ages and in plants at different flowering stages. The results are discussed in relation to biogenetic pathways and implications for taxonomic work.