山药总皂甙的提取研究

以山药中总皂甙提取率为考察指标,应用单因素试验和正交设计对山药总皂甙提取工艺中的浸提温度、乙醇的体积分数、浸提时间、料液比进行了研究。以薯蓣皂甙为标准,香草醛—高氯酸为显色剂,冰醋酸为溶剂,用分光光度计在波长为544nm处对山药总皂甙的含量进行了测定,得出山药总皂甙的最佳提取工艺条件是:浸提温度为60℃,浸提时间为6h,乙醇体积分数为80%,料液比为1∶8。     

Floral biology and artificial pollination in Dioscorea alata L.

Summary Floral biology of Dioscorea alata L. was studied. Anthesis occurred in male flowers by 12.30 h and in female flowers between 13.00 h and 14.30 h. Male flowers remained open for 4–5 hours and female flowers for 9–11 days.Natural pollination was practically absent but parthenocarpic fruit development was observed in rare cases. For hand pollination a simple and efficient pencil method was standardised. Pollen remained viable for 4–5 hours whereas stigma receptivity lasted for 9–10 days. The optimum time of pollination was found to be between 12.00 h and 15.00 h. Several factors like high relative humidity, atmospheric temperatures below 30°C and non-bagging the female flowers were found to promote fruit set.     

6种杀线剂对重茬山药土壤微生物数量、酶活性和养分含量的影响

为明确常用杀线剂对土壤环境的影响,采用土壤常规分析方法,研究2种化学杀线剂(阿维·噻唑膦和氟吡菌酰胺)和4种生物杀线剂(厚孢轮枝菌、淡紫拟青霉、辣根素和茶枯抑线生物菌肥)对土壤微生物数量、酶活性和土壤养分的影响。结果表明,与不施用杀线剂的对照相比,2种化学杀线剂对苗期土壤细菌和真菌数量均表现出显著(P<0.05)的促进作用,而至成熟期后土壤细菌和真菌数量均降至对照水平及以下。4种生物杀线剂中,茶枯抑线生物菌肥对苗期土壤细菌/真菌表现出显著(P<0.05)的抑制作用,对真菌数量表现出显著(P<0.05)的促进作用,在成熟期对土壤细菌数量和细菌/真菌表现出显著(P<0.05)的促进作用,而对真菌数量无显著影响。6种杀线剂施用后对土壤脲酶活性均无显著影响。2种化学杀线剂和生物杀线剂厚孢轮枝菌、淡紫拟青霉和辣根素对土壤酸性磷酸酶活性在苗期和成熟期分别表现出显著(P<0.05)的增强作用和抑制作用,茶枯抑线生物菌肥仅对成熟期的土壤酸性磷酸酶活性表现出显著(P<0.05)的抑制作用。茶枯抑线生物菌肥对苗期和成熟期的土壤蔗糖酶活性分别表现出显著(P<0.05)的抑制作用和促进作用,其他杀线剂则始终表现出显著(P<0.05)的抑制作用。6种杀线剂显著(P<0.05)影响土壤铵态氮、速效钾和速效磷含量。施用杀线剂后,土壤铵态氮和速效钾含量在苗期时与对照相比无显著变化,至成熟期后,除茶枯抑线生物菌肥处理的土壤铵态氮含量外,其他处理的土壤铵态氮和速效钾含量均显著(P<0.05)高于对照。苗期时,施用杀线剂各处理的土壤速效磷含量均显著(P<0.05)低于对照;但成熟期时,各处理的土壤速效磷含量无显著差异。综上,这6种杀线剂对土壤微生物、土壤脲酶和土壤养分的影响随着时间的延长可逐渐恢复,但对土壤酸性磷酸酶和蔗糖酶活性的作用效果持续时间较长,可在一定程度上干扰土壤中的有机磷矿化和碳循环。     

山药珠芽发生的解剖学研究

对山药地上珠芽的发生规律进行解剖学系统观察。结果表明:山药珠芽发生于主茎或侧枝顶端向下第三节位的叶腋处。由叶腋表皮下1～2层细胞进行平周分裂,增加细胞层数,随后第二、三层细胞进行平周和垂周分裂,形成一团分生组织的珠芽原基。在外观上呈现嫩绿色球形小珠芽时,内部已分化出顶芽及多处根原基。顶芽和根原基的基部均有壳状区,形成与内部结构的分界,并对芽和根向外方生长有着一定的影响。幼嫩珠芽的结构,最外为一层表皮,表皮以内的数层薄壁细胞排列较为紧密,其内方有三、四层分生组织组成的分生带,珠芽中部的薄壁细胞富含淀粉及蛋白质颗粒,外韧有限维管束散生于薄壁细胞之间。成熟珠芽与之相比,最外为木栓质表皮,其内方为木栓形成层形成的周皮。由于分生带的作用,中部薄壁细胞数量增多,并伴随着细胞的增大,形成了成熟珠芽的一定形态和体积。     

Silage preparation and nutritive value of Chinese yam by-product

The objective of this experiment was to determine the ensiling characteristics, nutrient composition and nutritive value of Chinese yam by-product (CYBP) silage treated without additive (Control), with lactic acid bacteria (LY), with dried beet pulp (BY), or with mixtures of lactic acid bacteria and dried beet pulp (LBY) for a fermentation period of 150 days. The nutritive value of CYBP silage was studied in an in vivo digestibility trial using wethers in a 4 × 4 Latin square design. Addition of lactic acid bacteria and/or dried beet pulp greatly improved fermentation quality of CYBP silage. The pH was reduced to below 4.0 and lactic acid was produced at above 4.6% on dry matter basis. There were no statistical differences among treatments in the digestibilities of dry matter, organic matter, crude protein and energy in the silages, but neutral detergent fiber and acid detergent fiber digestibility were higher ( P  < 0.001) in wethers fed BY and LBY silages compared to the control and LY silages. It was estimated that total digestible nutrient and digestible energy in the CYBP silage averaged 79.1% and 14.3 MJ/kg on dry matter basis. The study suggests that CYBP can be well preserved by making a silage and it is a good potential energy source for ruminant diets.     

山药炭疽病防治方法

炭疽病是近年来我国山药生产上经常发生的一种病害,随着山药种植面积的增大,该病呈逐年加重趋势,严重年份发病率在50%以上。文章综述了山药炭疽病的发生条件、规律、特点及症状表现,并介绍了农业防治、化学防治、植物源农药防治三种防治方法,展望了山药病虫害防治的发展趋势。     

7个山药品种对炭疽病的田间抗性比较

山药是我国重要的薯蓣类作物,在我国南方和北方均有大量种植。主要收集了山东省和河北省的山药品种7个,经过2年的大田种植,在种植过程中观察统计每个品种的炭疽病发生情况并进行对比。结果表明:温县怀山药、河北麻山药、河北小白嘴在整个生育期都没有发生炭疽病,大田表现对炭疽病的抗性比较强,菏泽鸡皮糙山药和温县铁棍在大田中的表现对炭疽病的抗性比较弱,曲阜牛腿山药和嘉祥细毛长山药对炭疽病的抗性位于中间。     

Effects of elevated CO2 concentration on growth and photosynthesis of Chinese yam under different temperature regimes

Chinese yam (‘yam’) was grown at different carbon dioxide concentrations ([CO₂]), namely, ambient and elevated (ambient + 200 μmol mol^?1), under low- and high-temperature regimes in summer and autumn, separately. For comparison, rice was also grown under these conditions. Mean air temperatures in the low- and high-temperatures were respectively 24.1 and 29.1 °C in summer experiment and 20.2 and 24.9 °C in autumn experiment. In summer experiment, yam vine length, leaf area, leaf dry weight (DW), and total DW were significantly higher under elevated [CO₂] than ambient [CO₂] in both temperature regimes. Additionally, number of leaves, vine DW, and root DW were significantly higher under elevated [CO₂] than under ambient [CO₂] in the low-temperature regime. In autumn experiment, tuber DW was significantly higher under elevated [CO₂] than under ambient [CO₂] in the high-temperature regime. These results demonstrate that yam shows positive growth responses to elevated [CO₂]. Analysis of variance revealed that significant effect of [CO₂] × air temperature interaction on yam total DW was not detected. Elevated-to-ambient [CO₂] ratios of all growth parameters in summer experiment were higher in yam than in rice. The results suggest that the contribution of elevated [CO₂] is higher in yam than in rice under summer. Yam net photosynthetic rate was significantly higher under elevated [CO₂] than under ambient [CO₂] in both temperature regimes in summer. Elevated [CO₂] significantly affected on the rate in yam but not in rice in both experiments. These findings indicate that photosynthesis responds more readily to elevated [CO₂] in yam than in rice.     

双酶法提取紫山药原花青素及其抗氧化性研究

为研究紫山药原花青素的最佳提取工艺以及抗氧化活性,以紫山药为试验材料,采用BoxBehnken中心组合试验设计和响应面分析,优化双酶法提取紫山药原花青素的提取工艺,并对其体外抗氧化活性进行评价。结果表明,最佳提取工艺为纤维素酶加酶量2.19%、果胶酶加酶量2.32%、酶解时间73 min、酶解温度45℃、液料比15 mL:1 g、pH 4.5,此条件下紫山药原花青素得率为93.06 mg/g。体外抗氧化试验结果表明,双酶法提取的紫山药原花青素具有明显的抗氧化性,对DPPH自由基(DPPH·)和羟基自由基(·OH)半数抑制率浓度IC50分别为0.165、0.267 mg/mL,清除能力强于维生素C。