坝光银叶树湿地园空气颗粒物浓度变化研究

在不同季节对深圳坝光银叶树（Heritiera littoralis）湿地园内不同地点的空气颗粒物浓度 （TSP、PM10、PM2.5 及 PM1.0）进行了 8:00、10:00、12:00、14:00 及 16:00 时共 5 个时间点的观测。结果表 明,空气颗粒物浓度在不同监测区域、季节和时间均存在显著差异（P<0.001）。深圳坝光银叶树湿地园 TSP、PM10 和 PM2.5 年均值低于II 级标准浓度限值,TSP 和 PM10 日均值低于II 级标准浓度限值,PM2.5 日均值低于I 级标准浓度限值。在空间上表现为古银叶树群落区域的空气颗粒物浓度最高,海边区域最 低;在季节上,较高浓度的TSP、PM10、PM2.5 出现在夏秋季,较高浓度的PM1.0 则出现在秋冬季;在时 间上表现为正午的空气颗粒物浓度最低。     

濒危植物珊瑚菜果实形态和解剖结构观察

[目的]为了能够全面了解国家Ⅱ级濒危植物珊瑚菜的果实形态解剖特征,探讨其在当归亚族乃至整个伞形科的起源与演化地位。[方法]利用普通电镜观察和石蜡切片法,对珊瑚菜的成熟果实外观及果实横切面解剖结构进行了观察。[结果]珊瑚菜分生果压扁类型为背腹轻度压扁,横切面呈近五角星状;分生果5个果棱比较发达,呈角状突起;果壁较其他伞形科植物发达,中果皮细胞层数较多,排列较紧密;果实维管束数目较多且比较发达。[结论]与其他伞形科植物相比,珊瑚菜特殊之处在于果棱具木栓质翅。这是由珊瑚菜果实横切面中维管束较发达造成的。通过与当归亚族中其他属的比较,推测珊瑚菜属在当归亚族中处于相对比较原始的位置。     

松嫩平原碱化草甸獐毛种群有性生殖的数量特征及营养繁殖特性的研究

通过对单优群落随机取样的调查与测定，分析了松嫩平原碱化草甸漳毛种群有性生殖的数量特征及营养繁殖特性。樟毛种群以营养生长和营养繁殖为主，成穗率仅为１５．７％，结实率为４１．６％。獐毛的匍匐茎在整个生长季均不断地增节伸长。至生长季末期，大多数匍匐茎可产生２０～２２个节，总长度可达２６９．５～３０４．５ｃｍ，节上可共产生８５．５～ｌ１１．４个营养繁殖株。不同月份的匍匐茎，其营养繁殖具有相同的规律性。匍匐茎的营养繁殖株在翌春存活与繁殖的数量最少者为１０株，多者达１３１株，基部１～２节无存活，３～１９节可形成１～２３株的营养繁殖株丛，最远存活的节营养繁殖株距母株２９４ｍ。     

Insecticidal and fungicidal activity of new synthesized chitosan derivatives

Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5 g kg(-1) in artificial diet. The most active was N-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625 g kg(-1), with an estimated LC50 of 0.32 g kg(-1). Treated larvae ceased feeding after 2-3 days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl)chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea, with EC50 values of 0.57, 0.57 and 0.52 g litre(-1), respectively. Against P grisea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5 g litre(-1). The effect of different substitutions is discussed in relation to insecticidal and fungicidal activity.     

深圳坝光银叶树湿地园林木有害生物调查及防控

对坝光银叶树Heritiera littoralis 湿地园开展有害生物调查,收集并鉴定有害生物72 种,其中有害杂草5 种、寄生植物2 种、病害20 种、虫害45 种。红火蚁Solenopsis invicta 和薇甘菊Mikania micrantha 属于外来入侵检疫性有害生物,八点广翅蜡蝉Ricania speculum 在公园内危害严重,对主要有害生物应加强预测预报、及时防治。     

DPX-MP062—a potent compound for controlling the Egyptian cotton leafworm Spodoptera littoralis (Boisd.)

The effects of DPX-MP062 [methyl 7-chloro-2,3,4a,5-tetrahydro-2-[methoxycarbonyl(4-trifluoromethoxyphenyl)carbamoyl] indeno[1,2-e][1,3,4] oxadiazine-4a-carboxylate] a broad-spectrum insecticide with a novel mode of action, on the Egyptian cotton leafworm, Spodoptera littoralis, were studied in laboratory experiments. Egg hatch was affected by high concentrations (125 mg AI litre^-1) of DPX-MP062. Larvae that hatched from treated eggs were significantly affected at concentrations of 12·5 mg AI litre^-1 and greater. Larvae were fed castor bean leaves treated with DPX-MP062; 1st-instar larvae were the most susceptible development stage. Pupation and adult formation were determined in assays with 5th-instar larvae. There was strong suppression of adult formation; 65 and 91% at 0·5 and 0·75 mg AI litre^-1, respectively. Highly affected larvae died before pupation; slightly affected ones reached pupation 2–4 days later, were smaller than larvae in the untreated control, and were sometimes unable to develop into normal adults. Comparatively high concentrations (50 and 100 mg AI litre^-1) of the test compound were necessary to affect adults by ingestion, but no effects from contact application could be determined at a concentration of 100 mg AI litre^-1. © 1998 Society of Chemical Industry     

北沙参外植体消毒方法研究

分别以北沙参田间栽培苗及温室盆栽苗的幼嫩叶片、田间高畦栽培苗的幼嫩根尖和温室水培苗的幼嫩叶柄为外植体,研究不同消毒组合对外植体污染率的影响。结果表明,75%酒精消毒20 s后再用0.1%升汞消毒5 min,接种外植体的存活率较高,且污染率较低。     

深圳盐灶银叶树种群的生物学特性研究

对深圳盐灶银叶树种群的生物学特性进行研究,发现该种群的实际分布面积仅0．7hm^2,个体数不足1500,且还在减少;年龄结构虽然呈近似金字塔形,但幼龄及中等个体数少,呈一定的瓶颈现象,其陆生亚种群年龄结构呈倒金字塔形．自然情况下,产种子少,种子萌发率低,幼苗向成苗转化率低;去外壳能缩短银叶树种子的萌发时间,但一定程度上增大银叶树幼苗的死亡率．研究结果表明,深圳盐灶银叶树种群已处于严重受威胁状况,亟需保护．     

银叶树育苗试验研究

银叶树是一种既能生长在潮间带,也能在陆地上生长的两栖性红树珍稀植物,我国野生种群数量少。试验表明:银叶树果实育苗宜采集成熟果实,即自然凋落在母树下的风干果,其成苗率显著优于直接采集自母树上的鲜果。风干果采集后应保湿处理,以城市自来水浸泡7 d后立即播种为佳。切除部分果皮有利于获得整齐苗与壮苗。果实不宜冷藏,建议保存温度不低于7℃。     

Impact of a Turkish isolate and a plaque-purified variant of SpliNPV-B on larval stage development of Spodoptera littoralis (Lepidoptera: Noctuidae) Boisd

Baculoviruses can alter the development and physiological status of their insect hosts. In the present study, two Spodoptera littoralis nucleopolyhedroviruses (SpliNPV-TR1 and SpliNPV-M2) were examined in terms of their effect on the stage development of S. littoralis at two doses/concentrations by inoculation of neonates or third instars. Both isolates had an acute pathological effect on neonates. However, larval development was prolonged (6-36 h) by either infection when neonates were infected. When third-instar larvae were inoculated, no mortality occurred until insects moulted to later stages. When the isolates were compared, more mortality occurred in the fifth instar with SpliNPV-M2 than with SpliNPV-TR1, whereas less mortality occurred in the sixth instar with SpliNPV-M2 than with SpliNPV-TR1. However, none of the isolates demonstrated a dose effect. Larvae died at 108-198 h post-inoculation at all infections, and none of them pupated. Larval development was retarded (0-126 h) for each stage when third-instar larvae were inoculated. Consequently, SpliNPV-M2 would be a more effective control agent than SpliNPV-TR1 for control of S. littoralis since it kills larvae at earlier developmental stages.