Growing tropical plants in N.Z. possibility

Press, Volume CX, Issue 32459, 20 November 1970, Page 10

Growing tropical plants in N.Z. possibility

A scientist whose findings have aroused world-wide interest because of their implications for the breeding of more adaptable and productive grasses and cereals is now working with the Plant Physiology Division of the Department of Scientific and Industrial Research in Palmerston North. He is Dr C. R. Slack, co-discoverer

of the “Hatch-Slack pathway” in photosynthesis. Dr Slack, a biochemist from the Colonial Sugar Refining Company’s research laboratories near Brisbane, is here on a New Zealand Climate Laboratory fellowship. Photosynthesis is the process by which plants use energy from sunlight to convert atmospheric carbon dioxide to sugars. The photosynthetic pathway is the series of chemical reactions involved. A few years ago it was thought that photosynthesis in all plants was via a particular series' of reactions known as the Calvin cycle. Professor Melvin Calvin, of the University of California, received a Nobel Prize for the research leading to discovery of this cycle. But at Brisbane, Dr Slack and Dr M. D. Hatch showed that in tropical grasses there is a distinctive set of additional reactions preceding the Calvin cycle. This more complex photosynthetic pattern has become known as

the Hatch-Slack pathway. It explains the ability of tropical grasses to grow more rapidly than temperate species, and scientists in many countries are now seeking ways to exploit it more widely in crop production. One approach on which much research is being done overseas is- the possibility of breeding the HatchSlack pathway into temperate species. Another of particular interest to New Zealand, and already being studied by the Plant Physiology Division, is that tropicargrasses and cereals may be adapted for use in more temperate climates. New Zealand summers provide sufficient light intensity but only marginally adequate temperatures for many tropical species. In Palmerston North, Dr Slack will collaborate with D.S.I.R. workers in attempts to determine just how low temperature exerts its limiting influence on photosynthesis in tropical species such as maize. “If we can find this out,” he says, “we may be able to find means of adapting these species better to New Zealand conditions.” In the accompanying photograph Dr Slack Is seen using a .radio-isotope counter to measure the activity of particular leaf enzymes.