The role of antioxidant system in freezing acclimation-induced freezing resistance of Populus suaveolens cuttings

We investigated the changes in the contents of H2O2, malonaldehyde (MDA) and endogenous antioxidants, the activities of protective enzymes and some critical enzymes involved in the ascorbate-glutathione (ASA-GSH) cycle as well as freezing resistance (expressed as LT50) and correlations mentioned above, in detail using Populus suaveolens cuttings. The purpose was to explore the physiological mechanism of the enhancement of freezing resistance induced by freezing acclimation at –20°C, and to elucidate the physiological mechanisms by which trees adapt to freezing. The results showed that freezing acclimation enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), monodehydroascorbate reductase (MDAR), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR). And it increased the contents of reduced ascorbate (ASA), reduced glutathione (GSH), dehydroascorbate (DHA) and oxidized glutathione (GSSG). However, H2O2 and MDA contents and LT50 of cuttings were decreased. LT50 in cuttings was found to be closely correlated to the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, H2O2, MDA, ASA, GSH, DHA and GSSG during freezing acclimation. This suggested that the enhancement of freezing resistance of cuttings induced by freezing acclimation may relate to the distinct increase for the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, ASA, GSH, DHA, and GSSG. In addition, the observed levels of APX, DHAR, MDAR, GR, ASA, DHA, GSH and GSSG were higher than those of SOD, POD and CAT during freezing acclimation. It indicated that a higher capacity of the ASA-GSH cycle is required for H2O2 detoxification, and growth and development of cuttings. Based on the obtained results, it can be concluded that the ASA-GSH cycle plays an important role in enhancement of freezing resistance of P. suaveolens cuttings during freezing acclimation.     

甜杨离体再生中玻璃化苗的发生与防治

由于甜杨不定芽的诱导过程中发生了玻璃化现象,为了恢复和逆转甜杨玻璃化苗,本试验采用正交试验设计L_9(3~4)对影响玻璃化现象发生的光照强度、琼脂浓度和蔗糖浓度等因子进行研究。结果表明,琼脂浓度对甜杨玻璃化苗恢复率的影响最大,达到极显著水平,蔗糖浓度和光照强度对甜杨玻璃化苗的恢复率影响不显著。当琼脂浓度为9 g/L,培养光照强度为3000 lx,培养基中蔗糖浓度为20 g/L时,甜杨玻璃化苗的恢复率最高,达到100%。由此可知,培养基中较高的琼脂浓度对甜杨玻璃化苗的防治与逆转有显著作用。     

草木樨愈伤组织的诱导和芽的再生

为了建立草木樨的高效再生体系和基因转化体系,以黑龙江草木樨为材料,用MS、1/2MS为基本培养基,添加不同种类和浓度的植物激素,对草木樨的愈伤组织培养和绿色芽点培养进行了研究。结果表明,诱导其愈伤组织的培养基以MS 2,4-D 1.0 mg.L-1 KT 0.3 mg.L-1为最好,愈伤组织的形成率可达90%;诱导绿色芽点的培养基以MS 2,4-D 0.2 mg.L-1 6-BA 1.0～1.5 mg.L-1为最好,芽点形成率可达45%。最后,将再生芽转入生根培养基1/2 MS IAA 0.5 mg.L-1上,生根率可达100%。     

The relevance of morphological plasticity in the simulation of competition between maize and Datura stramonium

The INTERCOM model was calibrated for Datura stramonium and maize with data from monoculture plots, and used to simulate the competition between the weed and the crop. The model adequately simulated the growth (leaf area index, above-ground biomass, plant height, yield) of both species in monoculture. In competition, the growth of D. stramonium and the competitive effect of D. stramonium on the growth of maize were clearly underestimated. Simulation of competition was improved when the observed morphological adaptations of D. stramonium under competitive light stress, as reflected in dry-matter partitioning, height growth and specific leaf area (SLA) were considered. Model analysis demonstrated that the observed changes in SLA and height growth were more relevant for the increased competitive ability of D. stramonium . The modification of the model in order to simulate the effect of shading by an overtopping species in the SLA of the shaded species improved model simulation of competition.     

野生曼陀罗重金属含量及其安全性评价

为探明野生曼陀罗各器官不同生育期金属含量状况,进而为其人工栽培选择合适生境及用药安全性提供科学依据,采用原子分光光度计法,分别对不同生育期采集的野生曼陀罗的根、茎、叶、果实等器官中(Pb,Cd,Hg,As,Cu,Fe,Mn,Zn,Cr,Ni)的含量进行分析测定。结果表明:1)不同生育期曼陀罗根、茎、叶和果实中的As、Hg、Cd和Pb的含量分别为0.11～1.16mg/kg、0.018～0.086mg/kg、0.021～0.19mg/kg和0.42～4.63mg/kg,与药用植物及制剂进出口绿色行业标准相比,均未超过对应元素的安全值。2)Cu在成熟叶片、成熟果实、成熟根、幼果和幼根中的含量分别为35.1mg/kg、26.0mg/kg、26.4mg/kg、23.9mg/kg和20.7mg/kg,均超过安全值(为20.0mg/kg),其中,成熟叶片中的含量超标严重,比安全值高75.5%,其他器官超标甚微。     

甜杨叶片高频率植株再生体系的建立

为了利用甜杨的抗冻性基因并利用生物技术手段对杨属进行抗寒性改良,本研究以甜杨叶片为外植体,研究了不同激素组合对甜杨不定芽诱导、分化及生根的影响,建立了甜杨叶片高频率植株再生体系。结果表明,诱导甜杨叶片不定芽分化的最适培养基配方为,MS+BA 0.5 mg/L+NAA 0.05 mg/L,再生频率及平均不定芽数分别为98.8%和23.0,最适生根培养基配方为,1/2MS+IBA 0.3 mg/L,生根率可达100%。为杨属的抗寒性改良及其分子育种实践奠定了基础。     

白花曼陀罗水浸液对家蚕的药杀效果研究Ⅰ

[目的]以家蚕为试验材料,研究药用植物白花曼陀罗对昆虫的药杀效果。[方法]取当年生新鲜和隔年白花曼陀罗植株,分别用常温水和沸水浸提;用浸提液分别浸泡家蚕和涂抹桑叶饲喂家蚕。[结果]不同浸提液间的药效没有明显差别;其浸提液对家蚕没有触杀作用;家蚕不食用双面涂药的桑叶,而食用单面涂药的桑叶后也不能致死,只表现出麻醉现象;3、4龄蚕在药液中浸泡24min后取出,还能恢复正常,而且生长良好。[结论]白花曼陀罗水浸液对家蚕无触杀作用,但对家蚕有麻醉作用。     

Two new amide alkaloids from the flower of Datura metel L.

Two new amide alkaloids were isolated from the alkaloidal fraction of Datura metel L. Their structures were elucidated as (E)-methyl 4-(3-(4-hydroxyphenyl)-N-methylacrylamido) butanoate and 6,7-dimethyl-1-D-ribityl-quinoxaline-2,3(1H,4H)-dione-5′-O-β-D-glucopyranoside on the basis of spectroscopic methods including HRESIMS, 1D and 2D NMR. Tropane alkaloids have for a long time been considered as characteristic ingredients of D. metel. However, the presence of amide alkaloids in D. metel was reported for the first time in this study.     

Mercurialis ambigua and Solanum luteum: Two Newly Discovered Natural Hosts of Tomato Yellow Leaf Curl Geminiviruses

The yellow leaf curl disease of tomato is caused by a complex of virus species, two of which, tomato yellow leaf curl virus (TYLCV)-Sar and TYLCV-Is, are involved in epidemics of southern Spain. Plants of Mercurialis ambigua and Solanum luteum showing abnormal upward leaf curling and leaf distortion collected in the vicinity of tomato crops were found to be naturally infected with TYLCV-Is and TYLCV-Sar, respectively. These weed species, as well as Datura stramonium and S. nigrum, which had also been found to be naturally infected by TYLCVs in the same region in previous studies, were tested for susceptibility to TYLCV-Sar or TYLCV-Is by Agrobacterium tumefaciens-mediated and by Bemisia tabaci inoculation. Results indicated that both TYLCV-Sar and TYLCV-Is were able to infect D. stramonium and M. ambigua, whereas only TYLCV-Sar infected S. nigrum and S. luteum. Implications for the epidemiology of TYLCV are discussed. This is the first report of M.ambigua and S. luteum as hosts of TYLCV.     

曼陀罗毛状根的诱导及其悬浮培养合成天麻素初探*

 利用A₄和R₁₆₀₁两种发根农杆菌菌株分别感染曼陀罗的嫩叶及嫩茎诱导产生毛状根。探讨了不同菌株、不同外植体、蔗糖预处理、外植体预培养与染菌时间以及外植体二次染菌等条件对转化频率的影响,并建立毛状根悬浮培养体系及转化外源底物对羟基苯甲醇合成天麻素。结果表明:A₄转化频率高于R₁₆₀₁;嫩叶转化频率最高;嫩叶最佳预培养时间为4 d;最佳染菌时间为5 min。HPLC法分析表明,悬浮培养毛状根能转化外源底物对羟基苯甲醇合成天麻素。