Caulogenic callus induction and adventitious bud formation from embryos of long-term stored seeds ofPicea jezoensis

Caulogenic calli with a high differentiation potency were induced from mature embryos ofPicea jezoensis seeds stored over a long time, for 29 years, resulting in the active formation of adventitious buds. Embryos began to induce calli within 3 weeks of cultivating on LP medium containing 3 μM BAP and 1 μM 2,4-D. Then, the calli proliferated and transformed into caulogenic calli with bud primordia in 8 weeks. The caulogenic calli increased actively with the addition of 500 mg/l ofl-glutamine in the medium. Furthermore, caulogenic calli, induced on LP medium containingl-glutamine, resulted in the formation of adventitious buds, which elongated after transferring the calli into LP medium with 0.1 μM BAP, but withoutl-glutamine. It appears that the number of adventitious buds and the process of shoot elongation are influenced by the kind of nitrogen contained in the medium for callus induction. A part of this study was presented at the 107th Annual Meeting of the Japanese Forestry Society (1996).     

丙硫磷对乙酰胆碱酯酶的抑制能力及其毒力与药效研究*

以两种对称型有机磷杀虫剂倍硫磷和敌敌畏为对照，利用Ｅｌｌｍａｎ法测定了不对称有机磷杀虫剂丙硫磷（Ｐｒｏｔｈｉｏｆｏｓ）对体外乙酰胆碱酯酶（ＡｃｈＥ）的抑制能力，并对褐刺蛾（Ｓｅｔｏｒａｐｏｓｔｏｒ－ｎａｔａＨａｍｐｓｏｎ）进行了３种杀虫剂的触杀毒力测定和野外药效试验。结果表明，丙硫磷为弱的ＡｃｈＥ体外抑制剂，酶抑制能力与毒力和药效间无相关性，抑制能力最差的丙硫磷对褐刺蛾幼虫毒力最强，野外药效也最好。说明丙硫磷的三元不对称结构和特殊的毒效基团与其高效低毒的特点之间可能有着密切的联系。     

植物铝毒害的产生及防治研究进展

土壤中的活性铝积累到一定程度时,即对植物产生毒害。土壤酸化是引起活性铝浓度增加的主要原因。土壤的酸度、富铝化程度、阳离子交换量、有机质含量、微生物种群和数量等因素都会影响到土壤中活性铝的释放,而增加钙的供应、施入有机质、增施磷肥或硅酸、种植牧草和绿肥、接种菌根菌剂、选育和种植耐铝植物等可防治铝对植物的毒害。     

怀槐心材提取物的防腐性能及其急性毒性试验研究

以怀槐的心材和树皮为原料,用乙醚、氯仿、丙酮、甲醇和水5种溶剂对其进行浸提,得到10种提取物.这10种提取物对白腐菌和褐腐菌的抑菌性能研究表明,怀槐心材的甲醇和丙酮提取物的抑菌性能良好.将心材的甲醇提取物和无机木材防腐剂酸性铬酸铜(ACC)用于对木材的室内防腐实验,根据腐朽后试样的失重率和扫描电子显微镜(SEM)的照片观测,得出甲醇提取物对白腐菌的防腐作用较好,对褐腐菌的防腐作用很弱,而ACC对两种菌的防腐作用较强.将心材甲醇提取物和ACC用于对斑马鱼的急性毒性试验,测得两者在24、48和 72 h 的半致死浓度,甲醇提取物分别为16.5、12.7、12.0 mg/L,ACC分别为3.2、2.5、2.0 mg/L;两者的安全质量浓度分别为2.26和 0.46 mg/L.     

6种氨基甲酸酯类农药对绿藻的毒性试验

以羊角月牙藻、四尾栅藻、斜生栅藻、普通小球藻和蛋白核小球藻5种绿藻作为供试生物,用6种氨基甲酸酯类农药对其进行96 h的急性毒性实验研究。结果表明,6种氨基甲酸酯类农药对5种绿藻都有不同程度的毒性,但不同藻类对不同农药的敏感性不同,四尾栅藻对速灭威、叶蝉散较为敏感,普通小球藻对这6种农药均较敏感,而蛋白核小球藻对6种农药均不敏感。     

杉木及其人工林自身特性对长期立地生产力的影响

本文系统地研究并综合了有关杉木及其人工林自身特性对长期立地生产力的影响的研究资料,认为杉木及其人工林自身的特性存在许多对地力维护不利的因素：（1）杉木凋落物发生晚,大量凋落物发生在14－15a前后;（2）杉木枯死枝叶具宿存特性,10－15a期间大部分枯死枝叶在树上,影响枯死枝叶的分解;（3）杉木凋落物养分含量低,如N含量只有阔叶树的30％－50％,因此枯落物营养元素积累低;（4）凋落物分解速率慢,分解速度在45％以下,而宿存于树上的枯死枝叶分解速率更慢;（5）杉木为速生树种,尤其在15a年前生长量大,吸收养分多,而养分归还少,杉木人工林养分循环速率不及40％;（6）杉木人工林培育密度较大,在15a前很少有林下植物生长,在20a后才有较好的林下植被发育,人工林长期处在单一的群落结构,很难发挥林下植被对地力的维护和改良作用。从现有的研究资料看,杉木及其人工林自身对地力维护有不利影响,是引起杉木林地土壤肥力及长期生产力下降的重要因素之一。     

生物措施缓解酸性土壤铝毒害研究进展

酸性土壤在世界上广泛存在,Al毒是酸性土壤限制作物生长和产量的主要限制因子之一.本文概述了酸性土壤Al毒害问题以及作物的耐Al机制,总结了遗传改良植物的耐Al性、向土壤或植物根际接种外生菌根真菌和其他耐Al微生物以缓解酸性土壤Al毒害的研究进展.以上措施在酸性土壤中的生态系统恢复具有应用前景.     

Effect of pyriproxyfen on developing stages and embryogenesis of California red scale (CRS), Aonidiella aurantii

During the past decade, the insect growth regulator pyriproxyfen has been the most used insecticide for controlling the California red scale (CRS), Aonidiella aurantii (Maskell), an important pest in citrus groves worldwide. The aim of the present research was to develop bioassays for determining the effect of pyriproxyfen on developing stages and embryogenesis of CRS that can serve as baselines for monitoring resistance. Pyriproxyfen was very effective against first- and second-instar nymphs of a susceptible strain of CRS; 0.1 and 0.2 mg AI L(-1), resulting in 80 and 100% mortality of first-instar nymphs, and in 62.5 and 91.7% mortality of second-instar nymphs respectively. According to probit analysis, the LC(50) and LC(90) values of pyriproxyfen for first-instar nymphs were 0.03 and 0.15 mg AI L(-1), and for second-instar nymphs they were 0.05 and 0.25 mg AI L(-1) respectively. Pyriproxyfen was quite effective on first-instar nymphs of a CRS field strain originating from a citrus grove where two successive applications of the compound had been applied. Mortality rates were 86 and 100% at concentrations of 0.2 and 0.4 mg AI L(-1) respectively. Pyriproxyfen suppressed embryogenesis when CRS females were treated with pyriproxyfen. Young CRS females treated with 1.0 and 5.0 mg AI L(-1) pyriproxyfen produced 6.6 N(1)/F and 2.4 N(1)/F as compared with 10.9 N(1)/F in untreated control.     

Residual toxicity of two insecticides on three field populations of Lygus lineolaris (Hemiptera: Miridae) collected along the St Lawrence valley in eastern Canada

Insecticides are still the single main pest control method employed today by most growers to mitigate damage done by the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae). In eastern Canada, the complex agricultural ecosystem, which may be described as a mosaic of farmlands dispersed among natural habitats (forest, prairies), allows tarnished plant bug adults to fly and move from sprayed to non-sprayed areas. In 2004 (late August to early September), three populations of L. lineolaris were collected from three mixed vegetation strips adjacent to orchards and vineyards along the St Lawrence valley: the Niagara Peninsula (Ontario), Dunham (Quebec) and La Pocatière (Quebec). Assays were done in the laboratory by confining adults in glass vials coated with dried residues. The estimated LC(50) values for the three populations varied from 11.2 to 16.8 x 10(-5) g L(-1) for azinphos-methyl and from 0.8 to 1.4 x 10(-5) g L(-1) for cypermethrin. In contrast to the Mississippi delta, no tolerance to insecticides was found in the populations collected. Possible explanations for this non-tolerance to insecticides includes a very low selection pressure as a result of the reduced number of insecticide treatments done in the context of the diversified agricultural landscapes encountered in eastern Canada which allow movements of adults from treated to non-treated areas.