[Comparative study on infection and degradation of Armillaria gallica and Phallus impudicus to fungus-growing materials].

The phenomenon that waste of fungus-growing materials in the planting process of Gastrodia elata is very common. It has been proved by practice that the used fungus-growing materials planted with G. elata can be used to plant Phallus impudicus. But the mechanism is unclear. In this study, we compared the different infested-capacity of Armillaria gallica and Phallus impudicus by morphological anatomy of the used fungus-growing materials. We also compared the differences on the two fungi consumed the main contents of fungus-growing materials, cellulose, lignin and hemicellulose, by using nitric acid-95% ethanol method, sulfuric acid method and tetrabromide method respectively, so that to explore the mechanism of A. gallica and P. impudicus recycle the fungus-growing materials, and to provide scientific basis for recycling the used fungus-growing materials of G. elata. The results showed that A. gallica had a strong ability to invade some parts outside the vascular cambium, but it had a weak ability to invade some parts inside the vascular cambium, while P. impudicus had a strong ability to invade the same parts. The contents of lignin and cellulose, which from inside and outside the vascular cambium of fungus-growing materials were significantly different. In the parts of outside the vascular cambium of fungus-growing materials, A. gallica degraded more lignin and cellulose, while P. impudicus degraded more hemicellulose. In the parts of inside the vascular cambium of fungus-growing materials, A. gallica degraded more cellulose, while P. impudicus degraded more hemicellulose. The present results suggested that A. gallica and P. impudicus made differential utilization of the carbon source in the fungus-growing materials to realize that P. impudicus recycle the used fungus-growing materials of G. elata. A. gallica used lignin and cellulose as the main carbon source, while P. impudicus used hemicellulose as the main carbon source.

[Effect of Panax notoginseng seedlings physiological response under simulated drought stress by polyethylene glycol (PEG 6000)].

The physiological effects of Panax notoginseng seedlings under simulated drought stress by PEG 6000 on antioxidant enzymes, osmotic substances and root activities were studied. The results showed that the activity of POD and APX in roots and leaves kept rising with increasing processing concentration and time. However, on the one hand, at the same processing time, SOD in roots and leaves firstly increased and then decreased with the increase of processing concentration. On the other hand, at the same processing concentration, SOD kept rising with the extension of processing time. In addition, the activity of CAT in roots and leaves tended to increase with the increasing concentration at the same processing time, while it increased at first and then decreased with the extension of time at the same concentration. The activity of SOD and APX in stem did not change obviously, whereas CAT activity in stem increased with the increasing processing time and concentration. With the increase of processing concentration and the extension of processing time, the MDA, soluble protein, proline content and root activity in leaves and roots apparently rose. Moreover, fluorescence signal of H2O2 and NO in root tip enhanced as the processing concentration increased after treated for 1 d. In summary, P. notoginseng seedlings could deal with drought stress by means of adjusting the system of antioxidant enzyme, permeating stress substances and impeded stress signal substances. Thus, when the concentration of PEG 6000 was more than 5%, it would have harm on P. notoginseng seedlings.