The effect of different nitrogen levels on yield and quality of stevia (Stevia rebaudiana bert.)

In the present work, the efficiency of different nitrogen doses (0, 50, 100, 150, and 200 kg ha^?1) on growth, yield, and quality of stevia (Stevia rebaudiana Bert.) was investigated in 2011–2013. The study was conducted in Antalya located in the Mediterranean Region of Turkey. Terra rossa type soil (LVx, FAO) characteristics of the experimental field were clay loam, with high amounts of lime (33,9%) and slightly alkaline (pH 7.7). The experiment was carried out in randomized block design with four replications. All the results were summarized as mean of three years. The highest fresh and dry biomass yields (26.75 t ha^?1 and 7.5 ha^?1, respectively) were obtained from 150 kg ha^?1 N dose and followed by 100 kg ha^?1 N dose (26.29 t ha^?1 and 7.24 ha^?1, respectively). Whereas the highest fresh and dry leaf yields (13.27 t ha^?1 and 3.82 t ha^?1, respectively) were realized in 100 kg ha^?1 N dose. Actually, all nitrogen doses gave higher biomass and leaf yields compared to the control. On the hand, major steviol glycosides (stevioside and rebaudioside A) in the leaf were not influenced by nitrogen levels. In conclusion, 100 kg ha^?1 N dose was found to be suitable for cultivation of stevia under field conditions.     

甜叶菊新品系的主要农艺性状及糖苷含量比较

[目的]对4个甜叶菊品系的主要农艺性状、茎叶产量及糖苷含量进行比较,为不同用途的甜叶菊育种提供一定的依据。[方法]对SR-1,SR-2,SR-3和SR-5共4个甜叶菊品系的株高、茎节长、一级分枝数、叶长、叶宽、叶长宽比和茎叶干重等进行考察,采用HPLC法测定其干叶ST和RA糖苷含量,并分析了各性状间相关关系。[结果]4个品系间植株形态、茎叶产量及糖苷品质均存在显著差异,ST苷含量和茎叶产量最高的品系为SR-5,RA苷含量和RA/ST值最高的品系为SR-2,综合RA苷含量和茎叶产量考虑,RA苷总量最高的为SR-3。茎叶产量同株高、茎节长、叶宽间相关显著。RA苷含量与干叶产量、干茎产量及茎叶总产量等呈显著负相关。ST苷含量则与各农艺性状间相关均不显著。[结论]提高甜菊的产量会一定程度影响甜叶菊的品质,但仍有可能选出既高产,品质又符合生产所需的优良甜叶菊新品种。SR-5品系可作为较好的药用型甜叶菊品系,SR-2可用作糖用型甜叶菊育种材料。     

甜叶菊中莱苞迪苷D、莱苞迪苷A含量测定方法的优化及应用

为比较不同品系甜叶菊中甜味品质较好的莱苞迪苷D(RD)、莱苞迪苷A(RA)含量组成,在传统C18、HSS T3、Amide色谱柱中选择适宜固定相建立高效液相色谱(HPLC)方法进行测定与分析。结果表明,HSS T3柱对甜菊糖苷选择性较好,可同时分离RA、甜菜苷(ST)、莱苞迪苷F(RF)、莱苞迪苷C(RC)、甜茶苷(RBS)、莱苞迪苷B(RB)、甜菊双糖苷(SB),其HPLC分析参数为:流动相32%乙腈和68%磷酸水(0.01%),等度洗脱,柱温40℃,波长210 nm,进样量10 μL,流速1.0 mL·min^-1;Amide柱对RD分离能力最佳,其HPLC分析参数为:流动相76%乙腈和24%水,等度洗脱,柱温40℃,波长210 nm,进样量10 μL,流速0.8 mL·min^-1。 分析比较12个扦插培育的甜叶菊品系,以编号2甜叶菊中RD含量及其占比最高,提示以其为原材料可生产含RD较高的甜菊糖苷;编号3、5、7、11甜叶菊中具较有高含量的甜菊糖苷(主要为RA),提示这些品种富含RA且甜菊糖苷产量较高;编号1、8甜叶菊中RA+RD占比较高,提示以其为原材料的甜菊糖苷甜味品质较好。本研究所建立的HPLC法为甜叶菊中RD、RA分析研究提供了方法参考,含量分析结果可为实际应用中选择适宜甜叶菊品种提供依据。     

甜叶菊新品系的主要农艺性状及糖苷含量比较

[目的]对4个甜叶菊品系的主要农艺性状、茎叶产量及糖苷含量进行比较,为不同用途的甜叶菊育种提供一定的依据。[方法]对SR-1,SR-2,SR-3和SR-5共4个甜叶菊品系的株高、茎节长、一级分枝数、叶长、叶宽、叶长宽比和茎叶干重等进行考察,采用HPLC法测定其干叶ST和RA糖苷含量,并分析了各性状间相关关系。[结果]4个品系间植株形态、茎叶产量及糖苷品质均存在显著差异,ST苷含量和茎叶产量最高的品系为SR-5,RA苷含量和RA/ST值最高的品系为SR-2,综合RA苷含量和茎叶产量考虑,RA苷总量最高的为SR-3。茎叶产量同株高、茎节长、叶宽间相关显著。RA苷含量与干叶产量、干茎产量及茎叶总产量等呈显著负相关。ST苷含量则与各农艺性状间相关均不显著。[结论]提高甜菊的产量会一定程度影响甜叶菊的品质,但仍有可能选出既高产,品质又符合生产所需的优良甜叶菊新品种。SR-5品系可作为较好的药用型甜叶菊品系,SR-2可用作糖用型甜叶菊育种材料。     

赤霉素对不同甜叶菊品系主要农艺性状、糖苷含量及产量的影响

喷施不同浓度的赤霉素（GA）于4种不同类型的甜叶菊品系叶表面,考察外源激素处理对其主要农艺性状、糖苷含量及糖苷产量的影响。结果表明：（1）赤霉素处理组同对照组相比,处理后株高、节长显著增长,且节间伸长效果主要集中在茎秆中部,叶长显著变短、叶宽显著变窄,叶长宽比值增大,单株干叶产量下降;赤霉素处理间,表现出一定的浓度效应,即随着赤霉素处理浓度增大,表现出一定的株高增加,叶长、叶宽减小的趋势。（2）就提高植株糖苷含量而言,100 mg/L的GA处理（A1）提高了SR1型甜叶菊的RA苷的含量,100 mg/L和300 mg/L GA提高了SR3品系ST苷含量,300 mg/L GA提高了SR2品系ST苷含量。（3）就糖苷产量而言,由于各处理下其干叶产量均显著下降,最终导致所有GA处理中,除300mg/L的GA处理显著提高了SR2的ST苷产量外,其余GA处理均不利于甜叶菊RA或ST糖苷产量的提高。     

The Effect of the Plant Age and Growth Period on the Nutritional Substance,Chlorophyll and Steviol Glycoside Rates in Stevia (Stevia Rebaudiana Bertoni) Leaves

Stevia (Stevia rebaudiana Bertoni) is a perennial and subshrub herb of the Asteraceae family, which originates from South America. Stevia has long been used as a sweetener and herbal medicine throughout the world. The most important feature of stevia is its sweetness with zero calories. This natural feature of Stevia is of utmost importance to everyone, especially those with diabetes and those who diet. In this study, samples were taken from Stevia rebaudiana plants of different ages (2, 3 and 4 years) in different growth periods (H1: 1 July, H2: 1 August, H3: 1 September and H4: 1 October) and an evaluation was made on the nutritional content values, the chlorophyll and sugar rates found in these samples according to the age and growth period of the plant. It was determined that the age of the plant and the harvesting period had an effect on the macro-micro nutritional elements, and chlorophyll and steviol glycoside rates contained in the stevia plant. In addition, as a result of correlation analysis, significant correlations were determined between the parameters measured in the plant. The results of the study demonstrated that in the cultivation of stevia, the best values were obtained from plants that were 3 years old and harvested in July.     

液质联用法分离鉴定甜叶菊叶片中的不同甜菊糖苷

为了进一步完善甜叶菊叶片中不同甜菊糖苷的测定方法,采用液质联用技术对多种甜菊糖苷标准品和‘鑫丰3号’甜叶菊叶片粗提物进行分析测定。最终共确定12种甜菊糖苷的出峰时间和顺序,其中甜茶苷、甜菊糖双苷和莱鲍迪苷E的出峰时间和顺序为首次确定。基于莱鲍迪苷A的测定标准曲线和多种甜菊糖苷的高效液相检测图谱结果确定‘鑫丰3号’叶片中的甜菊糖苷组成。‘鑫丰3号’叶片中共含有甜菊苷,莱鲍迪苷A、B、C、D、E和莱鲍迪苷F,甜茶苷,甜菊糖双苷9种甜菊糖苷,其中莱鲍迪苷D和E为痕量存在。本研究不仅为后续甜菊糖苷的测定提供了目前已有报道中最全面的紫外检测图谱依据同时也为新类型甜菊糖苷的发现和鉴定提供了方法参考。     

赤霉素对不同甜叶菊品系主要农艺性状、糖苷含量及产量的影响

喷施不同浓度的赤霉素(GA)于4种不同类型的甜叶菊品系叶表面,考察外源激素处理对其主要农艺性状、糖苷含量及糖苷产量的影响。结果表明:(1)赤霉素处理组同对照组相比,处理后株高、节长显著增长,且节间伸长效果主要集中在茎秆中部,叶长显著变短、叶宽显著变窄,叶长宽比值增大,单株干叶产量下降;赤霉素处理间,表现出一定的浓度效应,即随着赤霉素处理浓度增大,表现出一定的株高增加,叶长、叶宽减小的趋势。(2)就提高植株糖苷含量而言,100 mg/L的GA处理(A1)提高了SR1型甜叶菊的RA苷的含量,100 mg/L和300 mg/L GA提高了SR3品系ST苷含量,300 mg/L GA提高了SR2品系ST苷含量。(3)就糖苷产量而言,由于各处理下其干叶产量均显著下降,最终导致所有GA处理中,除300mg/L的GA处理显著提高了SR2的ST苷产量外,其余GA处理均不利于甜叶菊RA或ST糖苷产量的提高。     

Effects of the natural sweetener rebaudioside A on intake,nutrient digestion,rumen fermentation,and blood biochemical parameters in adult goats during summer

The effects of dietary rebaudioside A inclusion on feed intake, digestion of nutrients, rumen fermentation, and blood biochemical parameters of goats were evaluated in a replicated 3 × 3 Latin square study. Nine adult goats during summer were fed a basal forage/concentrate-based diet and the forage was chopped rice straw. The three dietary treatments were 0, 350, and 700 mg rebaudioside A per kg chopped rice straw on a DM basis. No significant improvement was observed in dry matter intake (DMI) of forage and diet among treatments. Nutrient digestibility of DM and organic matter (OM) showed a significant trend (p < .10) across groups. Rebaudioside A inclusion significantly (p < .01) increased the concentration of total volatile fatty acids in the rumen, however, there were no differences in concentration of ruminal ammonia, and molar proportions of acetate, propionate, and butyrate. About blood metabolites, increasing rebaudioside A in the diet caused a quadratic response in glucose and total protein, and albumin concentrations. Under the conditions of this study, supplementation with rebaudioside A at 350 and 700 mg/kg forage did not improve consumption of rice straw-based diet in adult goats in summer. However, the responses in digestibility, rumen fermentation, and blood metabolites appear to indicate the potential of rebaudioside A as a bio-active substance in goats.