涝害对甜叶菊光合及单株干叶产量的影响

利用温室盆栽法研究不同持续时间涝害对甜叶菊种质材料IS-1、QF-1、青甜杂4、JD-1、AL-4光合作用及干叶产量的影响。结果表明：随着涝害时间的持续,5份甜叶菊种质材料的叶绿素SPAD值、净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、蒸腾速率（Tr）及单株干叶产量均表现出不同程度的变化。短时间涝害处理（Ta：5d）对SPAD值、Pn、Gs、Ci、Tr及单株干叶产量影响均不显著;但随着渍水时间的持续叶片SPAD值、Pn表现出下降趋势：在Tb（涝害处理10d）中IS-1、QF-1、青甜杂4、JD-1、AL-4的SPAD值较正常水分处理分别下降21.29%、34.57%、27.84%、23.01%、17.59%,QF-1下降最快,AL-4下降最慢;Pn较正常水分处理分别下降65.88%、78.51%、74.44%、71.68%、59.58%,QF-1下降最快,AL-4下降最慢;Gs与Tr变化趋势与Pn相似,而Ci与Pn变化趋势相反;随着涝害持续时间的持续,甜叶菊单株干叶产量出现下降趋势,不同材料相同时间涝害胁迫单株干叶产量下降幅度不同,表明不同材料对涝害的耐受力不同。     

甜叶菊种子高效生产技术

根据生产实际,总结出甜叶菊种子高效生产技术。     

一个潜在催化莱鲍迪D苷合成的新型糖基转移酶

尿苷二磷酸糖基转移酶(uridine diphosphate glycosyltransferases,UGTs)催化糖基转移反应,与植物次生代谢密切相关。本研究根据甜叶菊(Stevia rebaudiana)转录组数据库,克隆到一个催化莱鲍迪D苷(rebaudioside D,RD)合成的新型糖基转移酶候选基因,对其开展生物信息学分析。结果表明,该基因开放阅读框长1380 bp,编码459个氨基酸,等电点(pI)预测为5.54,理论分子量约49.66 kD,系统发育分析表明该基因与向日葵中的UGT89A2同源,故将其命名为SrUGT89A2。构建pET28a-SrUGT89A2原核表达载体,并在大肠杆菌(BL21(DE3))中诱导表达得到重组蛋白,HPLC检测表明粗酶液能催化甜叶菊提取液形成一个新的色谱峰,该峰保留时间与莱鲍迪D苷一致。经进一步纯化UGT89A2蛋白,添加不同甜菊糖苷标准品为催化底物,但未鉴定出该蛋白催化的具体糖苷。该潜在催化甜菊糖RD苷合成的新型糖基转移酶基因SrUGT89A2的发现,为RD苷的生物合成和甜菊糖苷的生物途径研究提供新的理论依据。     

Response of stevia to nitrogen fertilization and harvesting regime in northeastern Portugal

The adaptation of stevia to the growing conditions of NE Portugal is assessed, including the tolerance of this species to cold temperatures, and the potential to produce biomass when grown as an annual crop and when subjected to various nitrogen (N) rates and two harvesting regimes. Almost all the plants died during the winter of 2014 (minimum temperatures peaked at ?8.0°C), making it necessary to replant the crop the following spring. With the best cutting regime (double cut) and N rate (150 kg N ha^?1), 1514.4 and 2390.0 kg ha^?1 of dry leaves were produced, respectively, in 2014 and 2015. Leaf chlorophyll concentrations estimated by the SPAD (Soil and Plant Analysis Development)-502 chlorophyll meter and a NDVI (Normalized Difference Vegetation Index) carried out by the Field Scout CM 1000 spectroradiometer showed significant differences among N rates, proving to be good indicators of plant N nutritional status. Based on the leaf analysis, provisional sufficiency ranges for N are proposed, namely 25–35 g kg^?1 for mid-summer and 15–25 g kg^?1 for early autumn. The fluorescence of chlorophyll a and the transient fluorescence intensity performed by the OS-30p+ fluorometer failed to show any stress induced by no-N control treatments in comparison to N-treated plants.     

Productivity of two stevia varieties under reduced irrigation and fertilization inputs

A 3-year field study was conducted in central Greece to determine the productivity of two stevia [(Stevia rebaudiana (Bertoni) Bertoni] varieties (‘Morita’ and ‘Candy-stevia’) under normal and reduced irrigation (100% and 75% of the evapotranspiration) and fertilization [1:0.8:1.1 or 1:0.4:0.8 N:P:K ratio in the first year and only N fertilization (100% or 74% of the recommended rate) in the second and third years] inputs. Averaged across years, stevia cv. Morita achieved greater dry leaf yield (3.48 t ha^?1) than the cv. Candy-stevia (2.85 t ha^?1). Irrigation and fertilization inputs did not significantly affect stevia cv. Morita dry leaf and steviol glycosides (stevioside plus rebaudioside-A) yields; however, decreasing irrigation and fertilization caused slight reduction of cv. Candy-stevia yields. In cv. Morita leaves, the concentrations of stevioside and rebaudioside-A ranged from 5.97% to 7.78% and 3.73% to 4.79%, respectively, while the corresponding concentrations in cv. Candy-stevia leaves were 8.21–9.36% and 3.89–6.33%. Conclusively, both stevia varieties could achieve satisfactory dry leaf biomass and steviol glycosides yield, even when grown under reduced irrigation (at 75% of evapotranspiration) and reduced N fertilization (74% of the recommended rate). Thus, stevia could represent an alternative crop to tobacco in the Mediterranean conditions.     

Bioorganic Nutrient Source Effect on Growth,Biomass, and Quality of Natural Sweetener Plant Stevia and Soil Fertility in the Western Himalayas

The effects of bioorganic nutrients on stevia were studied during 2011 and 2012 at Institute of Himalayan Bioresource Technology, Palampur, India. Bioorganic nutrient sources were evaluated in fourteen treatment combinations. Results showed that number of leaves plant^?1, leaf area plant^?1, and fresh and dry leaf biomass plant^?1 were significantly greater with the application of farmyard manure (FYM) 15 Mg ha^?1 + vermicompost (VC) 5 Mg ha^?1 + stevia seedlings treated with phosphorus-solubilizing bacteria (PSB) and azotobacter as compared to the control but plant height and the number of branches were not significantly affected by various treatments. This superior combination also resulted in considerably greater amounts of phosphorus (P) in stem (1.18 percent) and potassium (K) in leaf (2.39 percent). Stevia plants supplied with VC 7.5 Mg ha^?1 + stevia seedlings treated with PSB and azotobacter recorded greater stevioside (7.2 percent) and total steviol glycoside (8.4 percent). Application of organic manures in combination with biofertilizers enhanced soil organic carbon and available nutrient status of soil as compared to control.     

甜叶菊重要农艺性状关联分析

为挖掘与甜叶菊重要农艺性状显著相关标记,利用相关标记辅助甜叶菊育种。本研究对93份甜叶菊种质材料11个重要农艺性状描述性统计,并利用58对EST-SSR引物对其扩增,群体遗传结构分析,基于以上分析采用Tassel 5.0的GLM (generalized linear model)模型进行EST-SSR标记与甜叶菊11个重要农艺性状的关联分析。分析检测到10个标记与6个农艺性状极显著相关,各标记对表型变异的解释率范围为0.071 6～0.189 3,部分标记与2～3个农艺性状极显著关联。     

河西走廊发展甜叶菊的优势分析及超高产栽培措施

分析了甘肃河西走廊种植甜叶菊的优势因素,总结了沿祁连山冷凉灌区甜叶菊超高产栽培技术。     

鲁西南甜叶菊扦插育苗及优质高产栽培技术

2008年任城区为避免甜叶菊因品种退化、施肥不合理、病虫害加重造成产量降低、品质变差,出现卖叶难或叶贱伤农的不利局面,再创甜叶菊产业新辉煌,进行了甜叶菊扦插育苗及优质高产栽培技术的研究与应用,现已形成从品种更新、扦插育苗到收获贮藏的一整套比较完整的优质高产栽培技术。     

甜叶菊水浸液处理蚕豆根尖细胞的抗畸变效应

[目的]探究甜叶菊水浸液对蚕豆根尖细胞有无毒害或抗致畸作用,为甜叶菊作为饮品开发提供参考依据。[方法]利用微核检验技术,测试蚕豆根尖细胞染色体在N1甜-叶菊水浸液、CK＋-烟草水浸液、N2烟-草和茶混合水浸液以及N3烟-草、甜叶菊混合水浸液处理下的微核发生率。[结果]N1组的微核发生率与阴性对照差异不显著;N2组的微核抑制率达到81.09%;N3组的微核抑制率达到66.04%。[结论]甜叶菊水浸液对蚕豆根尖细胞无毒害;甜叶菊水浸液可明显降低烟毒所致的蚕豆根尖细胞微核发生率;甜叶菊水浸液对烟毒所致的蚕豆根尖细胞微核发生率抑制效果低于茶叶水浸液。