Relationships between leaf structure and photosynthetic pigment ratios in woody plants : A dissertation submitted in partial fulfillment for Bachelor of Agricultural Science (Honours) at Lincoln University, New Zealand

Abstract

Chlorophyll content, chlorophyll a:b ratios and chlorophyll:carotenoid ratios were examined in a study of seventy five woody plant species. In conjunction with this, four additional species were also examined in a glasshouse experiment. Photosynthetic pigment ratios for different photosynthetic tissue structures (lamina, needle, scale and cladode) were compared to discover any relationships between tissue structure and pigment ratios. There appeared to be no relationship.

Chlorophyll a:b ratios for woody plants were generally greater than those quoted in previous literature. It appears that chlorophyll a:b ratios for woody plants are usually greater than for herbaceous, and that the previously quoted range was based on a small variety of mainly herbaceous species. This was reinforced by pigment ratios for the three herbaceous species in the glasshouse experiment.

The chlorophyll a:b range established here was 2.20-4.64. Chlorophyll:carotenoid ratio range was established to be 2.53-13.56, higher than previously quoted.

It seems that some plants may be able to acclimate to a wide variety of lighting levels which vary chlorophyll a:b ratios.

Many aspects of this study require additional research.