[Soil enzyme activities of limestone degraded ecosystem at its different restoration phases].

The study showed that there was no distinct descending of enzyme activities along the soil profile of limestone degraded ecosystem, which were enhanced with progressive succession, and varied with vegetation characteristics, soil types, and soil enzyme properties. On the whole, soil enzyme activities enhanced in order of herb < Cupressuss funebris high forest< shrubbery, and under the same vegetation, limestone Cupressuss funebris high forest had higher soil enzyme activities than purple psammophytia. There was no significant correlation between soil enzyme activities and soil pH, while significant correlation was found between soil moisture content, soil total nitrogen content and soil enzyme activities, indicating that soil water and nutrient contents were the key factors of ecological restoration in this region. Different soil enzymes in the same vegetation-soil system as well as the same enzyme in the same soil type but at different restoration phases had different activities, so did for the same type vegetation but different soil type.

[Physiological and ecological effects of potassium on expansion of crocus corm].

The corm size of Crocus sativus, a well-known medicine, is a key limiting factor for its stigma harvest. A water cultural experiment with four different potassium (K) concentrations showed that the K content, chlorophyll content, relative ATP content and net photosynthetic rate in C. sativus leaves increased with improving K concentration, which enhanced the function of leaves to be metabolic source. On the other hand, the K absorbing ability and the contents of soluble sugars, vitamin C (Vc) and protein in new-born corms were increased with improving K concentration, which also strengthened the function of new-born corms to be metabolic sink. This study also showed that K could promote the new-born corm growth rate of C. sativus through strengthening the function of "source" and "sink".