植物生长调节剂对农作物和环境的安全性

随着科学技术和农业的发展,运用植物生长调节剂调控植物的生长发育和产量形成已经逐渐成为农业生产中不可缺少的重要措施。与传统农业技术相比,植物生长调节剂能够调控基因的表达,实现作物生长的“人为”调控。目前,国内外已将植物生长调节剂的研究和应用作为21世纪农业实现超产的主要措施之一。同时,植物生长调节剂作为一种散布到环境中的农用化学物质,其本身或降解产物是否危害非靶生物,产生不利的环境后果是人们更加关心的问题。笔者阐述了植物生长调节剂的定义和类型,及生产中应用的几种主要植物生长调节剂对土壤、水和作物的残留问题,及其对人类和动物的安全性,并对植物生长调节剂进行了应用展望,旨在为植物生长调节剂的合理使用提供科学参考。

一种具有植物激素活性的噻二唑席夫碱的合成及结构表征

【目的】寻找具有较高植物生长调节活性的物质。【方法】利用生物等排原理和亚结构连接法,对噻二唑母体进行修饰,设计并合成了1个新的噻二唑席夫碱,目标化合物的结构经红外光谱、核磁共振氢谱和元素分析加以确证。【结果】合成的化合物具有一定的植物生长调节活性。【结论】所合成的噻二唑席夫碱具有一定的研究开发价值。

植物雌激素治疗对绝经后妇女血浆一氧化氮及脑血流的影响

目的探讨植物雌激素大豆异黄酮对绝经后妇女大脑中动脉血流的影响及其作用机制。方法将60例健康绝经后妇女随机双盲分为大豆异黄酮治疗组(大豆异黄酮胶囊80mg/d,n=30)和安慰剂组(淀粉胶囊80mg/d,n=30),观察治疗12周后血浆雌二醇(E2)、一氧化氮(NO)浓度及大脑中动脉搏动指数(PI)的变化。结果与安慰剂组比较,大豆异黄酮治疗组12周后血浆NO浓度明显升高(P<0.01),而大脑中动脉PI明显降低(P<0.01)。服药前后NO与PI水平呈显著负相关(r=-0.56,P<0.05)。结论植物雌激素大豆异黄酮可增加脑血流量,其机制可能与NO介导内皮依赖性舒血管作用有关。

市售豆芽植物生长调节剂膳食暴露评估

目的了解某市市售豆芽中常用植物生长调节剂的含量,评估居民由于食用豆芽摄入植物生长调节剂的健康风险。方法采用单纯随机抽样的方法,采集某市农贸市场和超市销售的黄豆芽和绿豆芽样品,采用高效液相色谱-质谱法检测样品中4-氯苯氧乙酸(4-CPA)、2,4-二氯苯氧乙酸(2,4-D)、萘乙酸、赤霉素、吲哚丁酸的含量,结合广东省居民豆芽消费量调查数据,用点评估的方法评估居民对市售豆芽中植物生长调节剂的暴露水平。结果共抽取农贸市场和超市豆芽样品78份,其中黄豆芽45份、绿豆芽33份。黄豆芽中检出4-CPA、2,4-D含量均值分别为0.097、0.004 mg/kg,绿豆芽中4-CPA的含量均值为0.026 mg/kg;黄豆芽消费人群4-CPA、2,4-D平均暴露量分别为6.2×10^(-5)、2.5×10^(-6)mg/(kg bw·d),分别占健康指导值的1.03%、0.02%;黄豆芽高消费量人群(P97.5消费量)4-CPA、2,4-D暴露量分别为2.0×10^(-4)、8.3×10^(-6)mg/(kg bw·d),分别占健康指导值的3.33%、0.08%;绿豆芽消费人群4-CPA平均暴露量为1.6×10-5mg/(kg bw·d),占健康指导值的0.27%;绿豆芽高消费量人群(P97.5消费量)4-CPA暴露量为3.6×10^(-5)mg/(kg bw·d),占健康指导值的0.60%。豆芽样品中萘乙酸、赤霉素和吲哚丁酸的含量未检出。结论某市市售豆芽中检出微量植物生长调节剂4-CPA和2,4-D,对居民的膳食暴露水平远远低于健康指导值,经评估豆芽中5种植物生长调节剂的膳食暴露不会对居民构成健康风险。

茉莉酸对棉花单宁含量和抗虫相关酶活性的诱导效应

以植物生长调节物茉莉酸(Jasmonic acid,JA)为诱导子,以常规棉为研究对象,探讨了外源茉莉酸对棉花幼苗单宁和蛋白酶抑制素以及其它抗虫相关酶活性诱导的浓度依赖性和持久性,讨论了棉花抗虫相关物质的抗虫效果。结果表明,0.01、0.1和1.0 mmol/L茉莉酸都能在2周内诱导棉花单宁和胰蛋白酶抑制素(Proteinase inhibitors,PIs)含量增加,诱导多酚氧化酶(Polyphenol oxidase,PPO)、苯丙氨酸解氨酶(Phenylalanine ammonia-lyase,PAL)、过氧化物酶(Peroxidase,POD)和过氧化氢酶(Catalase,CAT)活性升高。对3种浓度茉莉酸的诱导效应进行分析表明,0.1 mmol/L茉莉酸对于诱导PIs、PPO、POD和CAT最有效,0.1和1.0 mmol/L茉莉酸对于诱导棉花单宁和苯丙氨酸解氨酶等效,二者的诱导效应均高于0.01 mmol/L。对茉莉酸诱导抗性的持久性进行分析表明,最佳诱导效应发生的时间各不相同:POD活性在JA处理后第1天最高,随后呈下降趋势,PIs和单宁含量分别在JA处理后第7天和第14天达最大值;JA处理后第1天和第7天的PPO活性无明显差异,但明显高于第14天;JA处理后第7天和第14天的PAL活性无明显差异,但明显高于第1天;JA处理后第1、7和14天棉花叶片的CAT活性均无明显差异。以上结果表明,茉莉酸可通过增加棉叶单宁和PIs含量、提高棉叶PAL、PPO、POD和CAT活性等增强棉花幼苗的抗虫性。

染料木素对体外培养胎鼠海马神经元细胞活力及其形态的影响

目的:观察染料木素(Genistein,Gen)对正常胎鼠海马神经元细胞培养条件下的活力及其形态影响。方法:取16～18d孕龄SD胎鼠海马组织进行原代培养海马神经元。采用MTT比色法检测0.01μg/ml、0.02μg/ml、0.04μg/ml、0.08μg/ml、0.16μg/ml、0.32μg/ml、0.64μg/ml、1.28μg/ml、2.56μg/ml、5.12μg/mlGen组及空白组对海马神经元分别作用24h、48h、72h的细胞活力及其形态变化。结果:1Gen对海马神经元细胞活力的最佳剂量为0.32μg/ml;Gen在0.01μg/ml、0.02μg/ml、0.04μg/ml、0.08μg/ml、0.16μg/ml、0.32μg/ml呈剂量依赖性增强;而0.64μg/ml、1.28μg/ml、2.56μg/ml、5.12μg/mlGen各组的细胞活性呈剂量依赖性下降。2Gen各剂量度组对海马神经元细胞的最明显促进生长时间是24h;Gen作用48h和72h时细胞活力则呈下降趋势。30.32μg/mlGen干预24h海马神经元细胞的形态最佳;0.01μg/ml、0.02μg/ml、0.04μg/ml、0.08μg/ml、0.16μg/ml、0.32μg/mlGen各组随剂量的增加对海马神经元细胞的生长促进作用明显增强,细胞形态呈轴突树突明显连接成网,胞体折光性好,细胞碎片少;大于0.32μg/mlGen剂量的效应结果则反之,随剂量增大其作用明显呈副效应变化,其细胞形态的轴突树突网状结构不明显,胞体折光性差,且呈崩解趋势,细胞碎片明显增。结论:Gen对体外培养胎鼠海马神经元细胞生长活力作用的最佳剂量为0.32μg/ml,最佳效应时间是24h。

Efficient in vitro Propagation of an Endangered Species Kolkwitzia amabilis Graebn

This study developed an efficient in vitro cultivation and propagation sys- tem for an endangered species Kolkwitzia amabilis using nodal segments as ex- plants. Multiple shoots were induced through axillary bud formation. The highest fre- quency of multiple shoot induction was achieved when the nodal segment explants were incubated in Murashige and Skoog （MS） medium supplemented with 4.44 pM 6-benzyladenine （6-BA） in combination with 0.54 μM a-naphthaleneacetic acid （NAA）, followed by treatment with 4.44 μM 6-BA in combination with 0.27 μM NAA. Shoot multiplication could be induced in MS medium supplemented with stand-alone 6-BA or 6-BA in combination with indole-3-acetic acid （1.71 μM） or NAA （0.27 or 0.54 μM）, with 6-BA and either compound, exhibiting a stronger effect on shoot multiplication. The optimum combination of plant growth regulators for shoot multiplication was 4.44 μM 6-BA with 0.27 μM NAA. The maximum rooting percentage was obtained in a half-strength MS medium supplemented with indole-3-butyric acid alone and in com- bination with NAA and 2,4-dichlorophenoxyacetic acid, but the best combination of plant growth regulators for rooting was 1.48 μM indole-3-butyric acid with 1.08 μM NAA and 0.05 μM 2,4-dichlorophenoxyacetic acid. The rooted shoots were trans- ferred to a greenhouse with a success rate of 100%.

Arabidopsis RAV1 is down-regulated by brassinosteroid and may act as a negative regulator during plant development

RAV1 is a novel DNA-binding protein with two distinct DNA-binding domains unique in higher plants,but its role in plant growth and development remains unknown. Using cDNA array,we found that transcription of RAV1 is downregulated by epibrassinolide (epiBL) in Arabidopsis suspension cells. RNA gel blot analysis revealed that epiBL-regulated RAV1 transcription involves neither protein phosphorylation/dephosphorylation nor newly synthesized protein,and does not require the functional BRI1,suggesting that this regulation might be through a new BR signaling pathway.Overexpressing RAV1 in Arabidopsis results in a retardation of lateral root and rosette leaf development,and the underexpression causes an earlier flowering phenotype,implying that RAV1 may function as a negative regulatory component of growth and development.

Responses of Halophyte Salicornia bigelovii to Different Forms of Nitrogen Source

Salt-affected soils are agricultural and environmental problems on a global scale. Plants suffer from saline stresses in these soils and show nitrogen （N） deficiency symptoms. However, halophytes grow soundly under saline conditions. In order to clarify the N nutrition of the halophyte Salicornia bigelovii, it was grown at several N levels （1, 2, 3, and 4 mmol L-1）, supplied in the form of NO3 or ammonium （NH4＋）, under high NaCl conditions （200 mmol L-l）. NH4^＋- fed plants showed better growth than NO3-fed plants at 1-3 mmol L-1N, and plants in both treatments showed the same growth at 4 mmol L-1 N. Nitrogen contents in NO3-fed plants increased with the N concentrations in solution; competitive inhibition of NO3- absorption by Cl- was observed under lower N conditions. In addition, shoot dry weight was significantly correlated only with shoot N content. Therefore, growth of NO3-fed plants was regulated by N absorption. In contrast, N contents of shoots in NH4＋-fed plants did not change with N concentration. Shoot Na content decreased with increasing N concentration, while K content increased. Dry weight was highly correlated only with K content in NH4＋-fed plants. These observations indicated that growth of NH4＋-fed plants was mainly regulated by K absorption.

Chlorocholine Chloride Induces Cacao Reproductive Development Leading to Improved Fruitlets Productivity of Cacao Trees in the Field

Fruitlet abscission （cherelle wilt） is a major factor contributing to lower productivity of cacao plantation in Indonesia. An attempt was made to reduce such cherelle wilt by spraying plant growth retardants （PGRs） on cacao trees at about 10 weeks before flowering session. The treatment was repeated every three weeks. Both the flowering initiation time and the number of flowers on the treated trees were improved significantly. With the most effective composition, flowers were initiated at 24 days after spraying （DAS）, where as the flowering initiation was 11-day later in the controls. At the 35 DAS, the chlorocholine chloride （CCC） 2,000 treatment induced about 20-80 folds more flowers than the controls. Extended observation was made to assess the treatment effect on the fruiting capacity. The treatments were found to improve fruiting ability by increasing the number of fruits set on the trees and shortening the time for fruit setting. At 20 weeks after the first spraying （WAS） there were on average 12.57 fruits per CCC 2,000-treated tree, as opposed to only 4.14 fruits per untreated tree. Analyses of the metabolites content in the flower cushions of the trees indicated that the reproductive growth is significantly correlated with the increased metabolites particularly the reduced sugar. Exogenous addition of sucrose to the PGR treatment gave greater improvement mainly in the fruiting. In conclusion, foliar spray of CCC induces flowering of cacao tress in the field that leads to improve the fruitlets productivity.

Development of an Efficient Plant Regeneration System for Pelargonium×Citrosum Vanleenii

[Objective]As a mosquito-repelling ornamental plant,Pelargonium×Citrosum Vanleenii(P.× Citrosum Vanleenii)is hard to be acquired because of its hybrid background,the paper was to a new regeneration system of(P.× Citrosum Vanleenii).[Method] By studying the influence of plant growth regulators(PGRs)on explant type(leaves and petioles),the optimal combinations of PGRs to maximize SELSs(somatic embryo-like structure)and buds were established.[Result]0.2 mg/L NAA+1.0 mg/L BA was best for LS(leaves segments)and 0.2 mg/L NAA + 1.5 mg/L BAs was best for PS(petioles segments).Cultured plantlets were successfully acclimatized in soil where they grew normally without any morphological variation.Although both LS and PS were usable,the leaf was a better explant for induction of embryogenic calli,somatic embryo-like structures and buds.[Conclusion]This work offered a rapid and efficient system for plant regeneration of P.×Citrosum Vanleenii.

助壮素中毒12例救治分析

目的总结助壮素中毒的抢救与治疗临床经验,提高抢救效率。方法 12例患者均给予洗胃、导泻、营养支持、生命体征监测等治疗,4例危重患者给予呼吸支持。结果 1例呼吸心跳骤停抢救无效死亡,11例救治成功痊愈出院。结论同其他中毒一样,洗胃、导泻、对症支持、加速药物排泄等观察治疗是救治成功的保证,出现呼吸衰竭积极给予呼吸支持,大多预后好,病死率低。