Abstract: Experiments of co-culture with Pavlova viridis and Tetraselmis tetrethele were carried out. Results showed a transparent phenomenon of interspecific competition between them. The competition was identified as an exploitation type through analysis. In the co-culture, both the growth rate (r) and the carrying capacity (K) of two species were affected, with a greater influence on P.viridis than on T.tetrethele, according to the comparision with those from the pure culture of two species. Each of interspecific competitive parameters of one species to the other was calculated, and the results showed that T.tetrethele possessed a more interspecific competitive capacity. Meanwhile, under the co-culture condition, both of the carrying capacity of two species were closely related to their respective inoculation density. The growth rate of P.viridis was in a positive proportion to its inoculation density, while a negative one existed in T.tetrethele.

Key words: irrigation amount, healthy index of seedlings, Huber value,  water use efficiency, Jatropha curcas