Study On The Growth Of Macadamia Proteoid Root And Physiological Effect Of Phosphate Fertilizer On Macadamia

The genus Macadamia, a member of the Proteaceae, is native to Australia and New Zealand. Two Macadamia species (Macadamia integrifolia Maiden & Betche and M. tetraphylla L.A.S. Johnson) produce edible seeds. Macadamia integrifolia is native to the rainforests of southeastern Queensland, and M. tetraphylla occurs farther south in the rainforests of New South Wales. Macadamia integrifolia is more tolerant of temperature extremes than M. tetraphylla. Their flowers are pendulous racemes. Flower color ranges from white to cream in M. integrifolia and cream to beige in M. tetraphylla. Hybrid flower colors range from cream to pink.Macadamia trees are intolerant of heavy frost. Frost damage begins to occur at -2.8°C (27°F), especially if the period of low temperature lasts for several hours. Macadamia trees are also intolerant of prolonged period of high temperature. But suitable drought and low humidity can promote flowering and fruiting of macadamia trees. They are suited to grow in fertile soil with good drainage and the pH value from 4.5 to 6.5.It has only been teens of years since macadamia industry started to develop in China so that the history of macadamia study is very short. With the flourish of Chinese economy, the desire to top grade food is ascending; as a result, the produced seeds of macadamia do not meet the need of so many consumers. From 1990s, some south provinces in China (Yunnan province and Guangxi province) have begun to plant macadamia trees and at the same time some studies on macadamia have been commenced. These studies include breed introduction, machining etc. However, the physiology study on macadamia has seldom been carried out.Considering of the application study, the variety 0 macadamia, which are extensively planted in south China, is used as the experimental material. The experiment is carried out to research thestructure of proteoid root and the relation between proteoid root and fungus, to investigate its formation condition and its effect on macadamia trees. In this paper, we try to observe the nexus between proteoid root and fungus, to probe into the correlation between the phosphate fertilizer and macadamia growth, to find out the right application of phosphate fertilizer in south China.1 Study on formation mechanism of macadamia proteoid rootThe experiment results showed that under the condition of keeping normal N, K and microelement, there is weak pertinency between the number of proteoid root and the phosphate fertilizer level. Proteoid roots will grow abundantly when the concentration of phosphate fertilizer 50mg/Kg(P2O5), while the concentration of phosphate fertilizer 300mg/Kg, there are few proteoid roots. This means that low concentration of phosphate fertilizer promote the growth of proteoid root, on the contrary, high concentration of phosphate fertilizer do restrain it.2 Study on the structure of proteoid root and the relation between proteoid root and fungusIt is first time to study on the structure and formation of macadamia proteoid root. The experiment results discover that the proteoid root of macadamia is the abnormality of normal root. Observed with the microscope, the proteoid root does not contain hyphae or spores that we can concluded the proteoid root is not fungus or fungoid.3 Study on the absorption of macadamia proteoid rootThe experiment results show that macadamia proteoid root is related to the absorption of main mineral nutrition, as a result the concentration in plant changes. Proteoid root promote the absorption of N, P, K, Mg. When the roots are taken off from the plant, the content of P in plant declined dramatically. Here is also some relation between proteoid root and macadamia photosynthesis efficiency. While proteoid root appeared massively, the photosynthesis efficiency and transpiration would descend. It is the first time to report the physiological function of macadamia proteoid root.4 Study on phosphate fertilizer on growth and development of macadamiaAccording to the results of the study on formation and physiology effect of proteoid root, the experiment on phosphate fertilizer and growth and development of macadamia trees is carried out We get the conclusion: different level of phosphate fertilizer led to diverse results to the growth and development of macadamia trees, to the elements content of leaves, and to the photosynthesis efficiency. Phosphate fertilizer enhanced growth and development of macadamia frees including the...