不同时期嫁接感染甘薯病毒病害SPVD对甘薯产量的影响

以苹果腐烂病菌、苹果轮纹病菌、棉花枯萎病菌、柑橘炭疽病菌与白菜黑斑病菌为供试菌，采用生长速率法测定25种中药材甲醇粗提物的抑菌活性。结果表明，在浓度为5．0 mg／mL 时，大部分中药材的甲醇粗提物对至少一种植物病原真菌都表现出不同程度的抑制活性，其中知母、青蒿、细辛与白鲜皮对3种供试植物病原菌的抑制率大于75％，而茜草与姜黄对4种供试植物病原菌的抑制率均在80％以上，具有广泛的抑菌谱。进一步采用系统溶剂法得到的茜草不同溶剂萃取物中，水饱和正丁醇相抑菌活性明显优于石油醚及乙酸乙酯相，表明茜草抑菌活性成分主要为中等及大极性化合物。

Effects of sweet potato virus disease infected by grafting at different growth stage on sweet potato yields

The antifungal activities of the extracts from 25 traditional Chinese medicines against 5 plant pathogenic fungi, Valsa mali, Botryosphaeria dothidea, Fusarium oxysporum f.sp. vasinfectum, Colletotrichum gloeosporioides, and Alternaria brassicae, were studied using the growth rate method. The methanol extracts of most of 25 traditional Chinese medicines showed antifungal activities against at least one plant pathogenic fungi. The inhibition rates of extracts from Anemarrhena asphodeloides, Artemisia annua, Asarum heterotropoides var. mandshuricum, and Dictamnus dasycarpus were more than 75% against 3 plant pathogenic fungi. The extracts from Rubia cordifolia and Curcuma longa also showed the significant inhibition rates of more than 80% against 4 plant pathogenic fungi at the concentration of 5 mg/mL. The methanol extract of R. cordifolia was further isolated to obtain four subfractions using different polar solvents. The bioactive screening exhibited that the subfraction of water-saturated n-butanol showed a better antifungal activity than those of petroleum ether and ethyl acetate, which indicated that the bioactive compounds of R. cordifolia should have the medium and large polarities.