Autumn growth and cold hardening of winter wheat under simulated climate change

Abstract

Plant responses to elevated CO₂ are governed by temperature, and at low temperatures the beneficial effects of CO₂ may be lost. To document the responses of winter cereals grown under cold conditions at northern latitudes, autumn growth of winter wheat exposed to ambient and elevated levels of temperature (+2.5°C), CO₂ (+150 µmol mol^?1), and shade (?30%) was studied in open-top chambers under low light and at low temperatures. Throughout the experiment, temperature dominated plant responses, while the effects of CO₂ were marginal, except for a positive effect on root biomass. Increased temperature resulted in increased leaf area, total biomass, total root biomass, total stem biomass, and number of tillers, but also a lower content of total sugars and a weaker tolerance to frost. The loss of frost tolerance was related to the larger size of plants grown at elevated temperature. The 30% light reduction under shading did not affect the growth, sugar content, or frost tolerance of winter wheat. At the low temperatures found at high latitudes during autumn, the atmospheric CO₂ increase is unlikely to enhance autumn growth of winter wheat to any significant extent, while a temperature increase may have important and major effects on its development and growth.     

虎纹捕鸟蛛毒素的提取及毒力的测定

报道了提取广西产虎纹捕鸟蛛 (Selenocosm ia huw ena) 毒素的方法。用冻干蛛毒对小鼠进行腹腔注射, 测定出虎纹捕鸟蛛毒素的LD50 为0.77 m g/kg, LD50的95% 可信限为0.72～0.82 m g/kg, 表明该毒素有很强的毒力。并观察到当用0.30 m g/kg 冻干蛛毒注射小鼠颅内时, 小鼠迅速抽搐5 s后即死亡     

披针叶黄华抗杉木炭疽菌活性物质研究

预试验中发现披针叶黄华地上部分乙醇浸提物具有抗杉木炭疽菌活性 ,进一步用不同溶剂 ,在不同 p H值下萃取得到 4个组分 .生测表明披针叶黄华中生物碱部分对杉木炭疽菌的抑菌活性最强 .其生物碱对杉木炭疽菌分生孢子萌发较对菌丝生长的抑制活性强 ,对杉木炭疽菌的分生孢子和菌丝的 EC50分别为 1 36.0 μg/m L和 1 555.0 μg/m L     

利用外源种质选育优良玉米自交系及强优势杂交种的实践与思考

以外引杂交种 785 99为基础材料分离获得优良玉米自交系齐 319。以齐 319为亲本与不同类群测验系杂交 ,所配组合均表现较强的杂种优势 ,特别是具有突出的抗锈病能力。其中鲁单 5 0即鲁原 92×齐 319优势最强。 1995～ 1997年在山东省区域试验和生产试验中产量居首位 ,并表现抗病、抗倒能力强 ,是目前生产上多抗性最好的优良品种之一 ,1999年山东省推广面积达 6 9 7× 10 4 hm2 。     

莲雾不同种的低温半致死温度及抗冷适应性

以叶片和成熟枝条为试材,应用电导法测定莲雾在不同低温下细胞膜透性的变化,配合Logistic方程求出低温半致死温度(LT50),评价6个莲雾种在不同降温时期的抗冷性,及同一时期不同部位的抗冷性,并结合露地栽培越冬表现进行验证。结果表明,在自然降温过程中,6个莲雾种的低温半致死温度均随气温的下降而不断降低,但下降幅度因种而异,1.69～2.97℃不等。6个种抗冷性由强到弱排序依次为水蒲桃>本地种>粉红种>紫红种>青色种>印度红。2 a生枝条的抗冷力最强,明显比叶片耐冷。冬季越冬表现与1月半致死温度测定结果基本一致,表明半致死温度可作为莲雾抗冷性评价的一个可靠指标。长时间低温加上霜冻,使露地栽培本地种、粉红种、紫红种的叶片和部分嫩梢受冷害,而印度红、青色种不能越冬成活。     

Practical capability of a DNA pool‐based genome‐wide association study using BovineSNP50 array in a cattle population

Genome‐wide association mapping for complex traits in cattle populations is a powerful, but expensive, selection tool. The DNA pooling technique can potentially reduce the cost of genome‐wide association studies. However, in DNA pooling design, the additional variance generated by pooling‐specific errors must be taken into account. Therefore, this study aimed to investigate factors such as: (i) the accuracy of allele frequency estimation; (ii) the magnitude of errors in pooling construction and in the array; and (iii) the effect of the number of replicate arrays on P‐values estimated by a genome‐wide association study. Results showed that the Illumina correction method is the most effective method to correct the allele frequency estimation; pooling errors, especially array variance, should be taken into account in DNA pooling design; and the risk of a type I error can be reduced by using at least two replicate arrays. These results indicate the practical capability and cost‐effectiveness of pool‐based genome‐wide association studies using the BovineSNP50 array in a cattle population.     

蒲公英内生真菌PG23抗癌活性的初步研究

研究药用植物蒲公英内生真菌PG23多糖对肺癌A549细胞的抑制作用。蒲公英内生真菌PG23通过培养,乙醇沉淀获得粗多糖、苯酚-硫酸法测定多糖含量,采用MTT法测定PG23多糖对肺癌A549细胞的抑制率,并计算半抑制浓度(IC50)。结果表明,PG23发酵液中多糖得率为2.754%,多糖含量为26.82%;对A549肺癌细胞的抑制率以第1天为最高;抑制率不与多糖浓度成比例,最佳作用浓度为14.42μg/mL,抑制率为87.63%(P<0.01),IC50为1.073mg/mL(24h)。PG23发酵液多糖对肺癌A549细胞具有较强的抑制能力。     

3种半数致死浓度计算方法之比较

通过对寇氏法、概率单位法及线性回归法等3种半数致死浓度(50%lethal concentration,LC50)计算方法的阐述,比较了其基本公式与操作方法等。结果表明不同时间的半数致死浓度均依线性回归法、寇氏法、概率单位法的顺序逐步升高,但差异性不显著(P>0.05)。在操作上,概率单位法和线性回归较寇氏法更容易掌握。     

Antiproliferative activity of Saponaria vaccaria constituents and related compounds

Total methanolic extracts of Saponaria vaccaria seed derived from several varieties, as well as various purified components obtained through successive chromatographic separations of total extracts were evaluated for their growth inhibitory activity in WiDr (colon), MDA-MB-231 (breast), NCI-417 (lung) and PC-3 (prostate) human cancer cells as well as the non-tumorigenic fibroblast BJ (CRL-2522) cell line using MTT colorimetric assay. Purified bisdesmosidic saponins segetoside H and I were further examined using microscopy and apoptosis assays. Bisdesmosidic saponins exhibited dose-dependent growth inhibitory and selective apoptosis-inducing activity. Growth inhibitory effects were particularly strong in a breast (MDA-MB-231) and a prostate (PC-3) cancer cell line. Total extracts exhibited a different preference being most active against a colon cancer cell line (WiDr). In a comparison of varieties, all of the total seed extracts exhibited similar dose-dependent activities, but with some variation in potency. Monodesmosidic saponins vaccarosides A and B, phenolic vaccarin, and cyclopeptide segetalin A, co-occurring seed substituents, did not exhibit activity. The non-tumorigenic fibroblast cell line BJ (CRL 2522) was growth inhibited but did not undergo apoptosis when treated with bisdesmosidic saponins at low micromolar concentrations. Saponin-rich extracts from Kochia scoparia seed and Chenopodium quinoa were also evaluated alongside Saponaria saponins but did not exhibit activity. Closely related Quillaja saponins exhibited activity but were less potent.     

香橼优良单株半同胞家系子代抗寒性研究

在南京六合地区对3年生24个香橼优良单株半同胞家系子代进行抗寒性测定研究,结果表明家系子代间抗寒性存在着显著的差异。田间观测-11℃自然低温下春江4#和香橼4#的抗寒性最强,受冻株率分别为86.67%和100%,平均受冻级别均为Ⅰ级,耐寒指数均为2.00;新世纪8#、春江7#和新世纪2#的抗寒性最差,受冻株率均为100%,平均受冻级别均达Ⅲ级,耐寒指数均大于3.00。室内抗寒力测定供试家系子代的半致死温度在-14.84℃～-7.05℃之间。春江4#和香橼4#的抗寒力最强,半致死温度分别为-14.84℃和-13.94℃;春江7#和新世纪2#的抗寒力最差,半致死温度分别为-7.91℃和-7.05℃。抗寒性评估结果一致。根据半致死温度,结合田间抗寒性观测,供试香橼家系子代抗寒性评估排序为春江4#>香橼4#>春江6#>春江5#>新世纪9#>新世纪10#>新世纪3#>香橼1#>新世纪7#>香橼7#>新世纪8#>香橼6#>香橼5#>春江3#>新世纪4#>新世纪6#>香橼2#>春江8#>新世纪5#>春江1#>新世纪1#>春江2#>春江7#>新世纪2#。