滴灌水分亏缺对柑橘前期光合特性的影响

为揭示滴灌水分亏缺及复水对柑橘叶片光合特性的调控效应,以9a生'不知火'柑橘为试材,在抽梢开花期(I期)、幼果期(Ⅱ期)各设置4个亏水处理,即轻度亏水(LD)、中度亏水(MD1)、偏重度亏水(MD2)和重度亏水(SD)处理,灌水定额分别为对照的85％、70％、55％和40％,并设置1个对照处理(CK),分析柑橘叶片光合...     

小陇山锐齿栎天然林的树种多样性和结构特征

运用林分结构参数混交度、角尺度、大小比数、直径分布、林层数和物种多样性指标,对小陇山百花林场王安沟经营区锐齿栎天然林样地的群落结构特征进行了研究.结果表明:锐齿栎天然林群落的树种组成十分丰富,树种多样性较高,群落中具有构成当地森林群落的主要树种,结构特征为复层异龄林;在水平结构方面群落中,林木个体分布的角尺度均值为0.489,林分内林木整体分布格局属随机分布;群落的树种隔离程度较高,平均混交度为0.598,处于强度和极强度混交的林木比例高达78.6%;群落中树种以胸径作为比较指标的林木个体的优势排列顺序为:白桦>湖北花楸>漆树>锐齿栎>三桠乌药>华山松>少脉椴>鹅耳枥>青榨槭>膀胱果;在垂直结构方面,群落的平均林层数为2.3层,垂直结构复杂,分化明显.     

20个茶花品种遗传关系的ISSR分析

采用ISSR分子标记技术对茶花品种群中有代表性的20个国内外茶花品种进行了品种间遗传关系的分析.从60对随机扩增引物中筛选出了21对扩增带型清晰及重复性好的引物序列,共扩增出153条带,其中146条呈现多态性,多态性条带比例为95.4%;Nei's基因多样性指数介于0.40～0.48,Shannon信息指数在0.57～0.67,基因分化系数介于0.5～0.7,基因流值介于0.2～0.5,遗传相似系数介于0.50～0.74,平均为0.63.参试的20个茶花栽培品种间遗传差异相对比较窄;结合花型形态学特征与UPGMA聚类分析结果,可将20个茶花品种分为2个大类群.此外,结果显示:ISSR分子标记适用于分析山茶品种间遗传多样性和亲缘关系.     

Progress in Controlled Breeding of Summer Flounder,Paralichthys dentatus,and Southern Flounder,P. lethostigma

ABSTRACT

The sum mer floun der, Paralichthys dentatus, and the south ern floun der, P. lethostigma, are high value flat fish spe cies and im -por tant can di dates for com mer cial aquaculture in the east ern U.S. Wild-caught adults of both spe cies have been spawned ei ther nat u rally or by hor mone-in duc tion dur ing their first year in cap tiv ity, but spawn ing suc -cess and fre quency of vo li tional spawnings im proves with size/age and ha bit u a tion (>1.5 year) to cap tiv ity. Con trolled-en vi ron ment tanks (2.5-10 m³) sup plied with re cir cu lat ing sea wa ter (32-36 ppt) are used for photo -thermal con di tion ing of broodstock to fa cil i tate en vi ron men tal con trol, ob ser va tion, han dling, and feed ing. Stocking den si ties of 1.7-4.11 kg/m³and sex ra tios of 1-2 males:1 fe male are rec om mended, but op tima have not been de ter mined. In the sum mer floun der, com mer cial hatch er ies use hor mone-in duced spawn ing of photothermally con di tioned fish to sup -ply fingerlings year round. In tra mus cu lar im plan ta tion of a slow-re lease LHRHa pel let (dose ～100 μg/kg) into fe males with max i mum fol li cle diameters >500 μm or with mean oocyte di am e ters rang ing from 258-456 μm in duces re pet i tive ovu la tion and spawn ing. Com mer cial culturists pres ently opt for strip spawn ing, us ing a “light ta ble” to es ti -mate time of ovu la tion, but hor mone-in duced vol un tary spawn ing and nat u ral spawn ing with out hor mone in duc tion could be come more prev a -lent with lon ger-term ac cli ma tion and do mes ti ca tion. In the south ern floun der, im plan ta tion of a slow-re lease LHRHa pel let (～100 μg) has also in duced re pet i tive ovu la tion and spawn ing, al low ing mul ti ple strip spawn ing or vo li tional spawn ing in fe males with max i mum fol li cle di -am e ters > 500 μm. Large num bers of vi a ble em bryos have also been pro -duced through nat u ral spawn ing with out hor mone in duc tion. Through photothermal ma nip u la tion, the nat u ral spawn ing pe riod has been ex -tended by 2-3 months, but ad di tional stud ies are needed to pro duce fingerlings year round. A fun da men tal prob lem in the con trolled re pro -duc tion of both the sum mer floun der and south ern floun der is the vari -abil ity in num ber of eggs and the fer til ity rates among fe males and among con sec u tive spawns from the same fe male. More pre dict able rates of ovu la tion, as well as of fer til iza tion and hatch ing, are needed to lower costs of seed pro duc tion. Vari able spawn ing suc cess can be at trib -uted in large part to in con sis tent male per for mance and in ad e quate spermiation. Hor mone treat ments used to in duce ovu la tion in fe males have been in ef fec tive in in duc ing spermiation in males, and al ter na tive ther a pies are needed. In fe males, egg qual ity may pre sum ably be im -proved by op ti miz ing nutri tions, en vi ron men tal con di tion ing, and hor -mone doses and re lease rates. To date, adult broodstock are ob tained from the wild, and the po ten tial for se lec tive breed ing or for pro duc ing interspecific hy brids re mains un tapped.     

甜叶菊组织培养研究进展

从无菌繁殖体系、培养基和培养条件的选择、愈伤组织的诱导与分化、芽分化和继代增殖培养、生根培养及组培苗的移栽等方面综述了甜叶菊组织培养方面的研究。并提出了甜叶菊组织培养的研究方向。     

Neue Art? Invasive Art? Hauptsache Bestimmung!

Zusammenfassung Mit der Bezeichnung Invasive Art werden nicht allein vitale Qualitäten einer gebietsfremden Tier- oder Pflanzenart ausgedrückt, sondern auch die Resultate einer Folgenabschätzung. Neobionten haben nicht nur Einfluss auf das natürliche Artengefüge eines Gebiets, sondern oft auch quantifizierbare wirtschaftliche Auswirkungen. Als besonders problematisch für Land- und Forstwirtschaft haben sich in dieser Hinsicht vor allem die Neozoen erwiesen. Deren unbemerkte Einschleppung und Etablierung hat oft kostenintensive Maßnahmen zur Folge, um Schäden und Einbußen zu verhindern. Sichere Erkennung und Bestimmung neuer Arten ist die unabdingbare Basis für alle weiteren Schritte: für Folgenabschätzungen, rechtliche Regelungen oder Maßnahmen. Den Pflanzenschutzdiensten der Länder kommt hier eine entscheidende Rolle zu: nicht nur mit Durchführung phytosanitärer Kontrollen, sondern vor allem mit sicherer Diagnostik: durch erfahrene Spezialisten für Entomologie und Nematologie mit breitem Kenntnisspektrum und geschult in der Erkennung wirtschaftlich bedeutsamer Tierarten.     

麋鹿同性爬跨的行为研究

麋鹿同性爬跨是其发情季节的一种行为表现。麋鹿同性爬跨有一定的时间性,主要选择在发情季节的5:30—7:30和17:00—18:30,早晨同性爬跨的出现比异性爬跨交配提前1 h,傍晚同性爬跨与异性爬跨交配时段相同。麋鹿同性爬跨与其年龄具有相关性,研究结果表明:6—9岁雄鹿是同性爬跨的主体。麋鹿同性爬跨的行为表现对环境具有一定的选择性,在麋鹿同性爬跨的行为中,同性爬跨的行为主要出现在视野较好的平坦开阔地和鹿群的外周边缘地。     

The role of isolated old oak trees in maintaining beetle diversity within larch plantations in the central mountainous region of Japan

Old oak trees (Quercus crispula Blume) that are remnants of former old-growth forests have been isolated singly or as small patches within a matrix of conifer plantations in the central mountainous region of Japan. Fifty-six aerial Malaise traps were deployed around seven isolated oak trees within larch [Larix kaempferi (Lamb.) Carrière] plantations and at seven larch plots within larch plantations. The species richness and composition of beetles (Cerambycidae, Curculionidae, Elateridae, Chrysomelidae, and Lycidae) around the oak trees were compared to those in the larch plantations. Species richness was higher around the oak trees than in the larch plantations, and the species composition differed. A number of saproxylic beetles were characteristic of isolated old oak trees. These results emphasize the importance of isolated old oak trees for maintaining beetle diversity in larch plantations and raise the possibility that further losses of these isolated oak trees could eliminate many individuals and reduce beetle diversity in larch plantations.     

聚合酶链反应检测4种猪源细胞系中的内源性反转录病毒

为了建立检测猪内源性反转录病毒（porcine endogenous retrovirus,PERV)的特异性方法，根据巳发表的PERV的序列，设计并合成了针对PERV核心蛋白（gag）、多聚酶（pol)、囊膜蛋白（env）基因的3对引物，预期扩增片段分别为361、150、265bp。应用PCR技术检测了PERV在4株猪源细胞中的整合情况。结果表明，在所有被检细胞的基因组中均存在有PERV的前病毒序列，应用RT-PCR检测上述4株猪源细胞中PERV特异性MRNA的表达，结果均为阳性。试验还对建立的上述2种方法的特异性进行了探讨，结果表明试验建立的PERV检测法具有较高的特异性。该方法的建立为进一步研究PERV奠定了基础，还可对异种移植动物模型及异种移植受体进行病原安全性监测。     

Effect of short‐term fasting and re‐feeding on growth,digestive enzyme activities and antioxidant defence in yellowfin seabream,Acanthopagrus latus (Houttuyn, 1782)

An 80‐day feeding trial was conducted to evaluate the influence of different short‐term fasting and re‐feeding strategies on growth and physiological responses in yellowfin seabream, Acanthopagrus latus (2.4 ± 0.2 g) fingerlings. The fish were subjected to four different feeding regimes, and the control group fed four times daily to apparent satiation throughout the whole feeding period, while the other three groups were deprived for 2, 4 and 8 days followed by 8, 16 or 32 days of re‐feeding (F₂R₈, F₄R₁₆ and F₈R₃₂, respectively) in repeated cycles for 80 days. The fish in the control and F₂R₈ groups had the highest and the lowest total length, respectively (p < .05). Moreover, fish exposed to F₄R₁₆ had the highest hepatosomatic indices, while control fish had the lowest hepatosomatic indices (p < .05). Fish in the F₂R₈ group relatively had higher catalase and glutathione‐S‐transferase activities than other groups (p < .05). Furthermore, total protease, α‐amylase and alkaline phosphatase activities in the F₄R₁₆ and F₈R₃₂ were higher than the F₂R₄ and control groups (p < .05). Overall, this study showed that compensatory growth in weight and length and digestive enzyme activities were observed in the F₄R₁₆ and F₈R₃₂; however, the increase in the activity of antioxidant enzymes in the F₈R₃₂ group indicated that oxidative stress remained after 80 days of re‐feeding in the liver.