Species fundamentals the key to long-term pastures

摘要

It is becoming increasingly obvious that Australian native pastures are not the poor cousins of "introduced" pasture species, as many farmers once thought. In fact, some aspects of their growth make them "smart pastures". An interesting feature of Australia's grasslands is the way the two major perennial grass classifications - C3 and C4 - have evolved to take best possible advantage of the continent's difficult "freezer to frypan" climate. C3 and C4 plants are groups of species that use different photosynthetic pathways to grow. Photosynthesis is the process that plants use to convert carbon dioxide (CO_2) and water, in the presence of sunlight, to carbohydrates. These are the building blocks for plant growth. There are two different photosynthetic pathways plants can use. Plants using the C3 pathway rely on the enzyme, rubisco, to fix carbon atoms from carbon dioxide in the air. The first stable product in this process is based on three carbon atoms, hence the C3 pathway label.