Altitudinal distribution of several eucalypt species in relation to other environmental factors in southern New South Wales

Four problems associated with studying the altitudinal distribution of eucalypt species are examined: the lack of specific physiological relationship between altitude and plant growth, the influence of other environmental factors, the availability of suitable data and the need for statistical analysis. Presence/absence data for eucalypt species were obtained from several sources. Probability of occurrence in 100 m zones is determined for E. maculata, E. muellerana, E. fastigata, E. sieberi, E. dalrympleana and E. pauciflora. The influence of other factors is demonstrated for several species using direct gradient analysis. Aspect is important for E. fastigata and E. rossii in addition to altitude and rainfall. The statisical model used was the logit-linear model: log (p/I– p) = linear function of environmental variables where p is the expected probability of being present for a given combination of environmental variables. Two examples are presented. E. dalrympleana can be predicted from altitude, rainfall, radiation index (measure of aspect) and an interaction term between altitude and aspect. E. rossii presence is predicted by altitude, rainfall, radiation index and geology. Altitude is transformed into an estimate of mean annual temperature which is shown to clarify some overlaps of species distribution. It is concluded that use of data collected for other purposes can be used in a generalized linear model for presence data to show the complex correlations which exist between the altitudinal distribution of some eucalypts and other environmental factors.     

Enhancing the Anaerobic Response

Proteome analysis, and more recently DNA chip technology, hasled to the identification of a large number of genes that areimplicated in the anaerobic response of plants. As a result,an increasingly complex picture of the response in terms ofbiochemical and regulatory processes is emerging. A challengeis to find out more about the function of these newly identifiedgene products, and how they contribute to flooding tolerance.Our approach has been to manipulate levels of candidate geneproducts (using sense and antisense constructs) in the modelsystem Arabidopsis thaliana, combined with biochemical and phenotypicanalysis of the resulting transgenic plants.     

Synchronization of larval emergence in winter moth (Operophtera brumata L.) and budburst in pedunculate oak (Quercus robur L.) under simulated climate change

1. The hypothesis that a 3 °C elevation in temperature and doubled CO₂ concentration would have no effect on the synchronization of winter moth egg hatch with budburst in oak was tested by comparing the separate and interactive effects of ambient and elevated (+ 3 °C) temperature and ambient and elevated (doubled to 340 p.p.m.) CO₂ in eight experimental Solardomes. In addition, an outdoor control was compared with the ambient temperature/CO₂ treatment combination.
2. Elevated temperature accelerated darkening (preceding egg hatch by about 5–10 days) and hatching of eggs developing off the trees; elevated CO₂ had no effect. The same effects were observed in eggs developing on the trees.
3. Within treatments, date of egg hatch was the same on trees with early or late budburst.
4. Egg darkening and budburst were closely synchronized at both ambient and elevated temperatures.
5. Both eggs and trees required fewer cumulative heat units (day degrees > 4 °C), for hatching and budburst, respectively, at ambient than elevated temperatures. The requirements in the outdoor control treatment were similar to those in the ambient Solardome treatment.
6. Egg hatch between 10 and 25 °C, on a temperature gradient in the laboratory, required a constant number of heat units; fewer were required below 10 °C.
7. Elevated temperatures, in the Solardomes and the field, delayed adult emergence from the pupae.
8. The results suggest that a general increase in temperature with climatic change would not affect the closeness of the synchronization between egg hatch of winter moth and budburst of oak.