几种培养液对水螅种群增长影响探究

通过对水螅的培养来探究了几种培养液对水螅种群增长的影响。结果表明:自来水作为培养液,水螅种群密度及种群瞬时增长率最大,其次为白开水和矿泉水,蒸馏水组水螅种群密度和种群瞬时增长率最小。故自来水最适合作为水螅培养液,其次为白开水和矿泉水,蒸馏水不适合作为水螅培养液。     

半干旱黄土区蓝藻液体培养条件研究

以半干旱黄土区藻类结皮中的蓝藻为研究对象,对其室内液体培养所需营养、光照及温度条件进行研究,揭示不同条件下蓝藻生长的规律。结果表明:N、P浓度不同藻种生长情况不同,N10、P1浓度下藻种生物量最大;不同光照时间对比研究发现,光照12h藻种生长稳定,而且生物量高峰值最大,长时间光照16h繁殖快衰亡也快,生长不稳定;温度也是影响藻种生长的重要条件,15℃、室温和20℃时,藻种生长均比较稳定,但15℃藻种生物量一直比较低,35℃条件下,藻种生长不稳定。     

印度东北地区一种极频危和特有树种(Ilex khasiana Pork.)再生生态学及种群现状

在5个典型自然种群Mylliem(种群1)、Upper Shillong(种群2)、Shillong Peak(种群3)、Laitkor(种群4)和Nongpiyur(种群5)中,详细研究了冬青树(Ilex khasiana)种群结构和再生生态学,旨在探究种群结构和再生能力的影响因素.在全光照(100%),中等光照(50%)和低光照(30%)三种光强度条件下,实验观察表明:在中等和低光照条件下的种苗成活率和生长状态好于在高光照条件下的种苗成活率和生长状态.成年树种群(≥5cm dbh)的密度直径分布揭示了一种再生种群的典型特征.对植被的破坏和人类其他干扰导致森林树冠疏开使光照增强,造成自然种群(L khasiana)幼苗的高死亡率.本研究结果对制定适当的物种保护措施有重要价值.     

后斑小瓢虫对竹茎扁蚜的控害潜能

【目的】通过室内测定后斑小瓢虫[Scymnus(Pullus)posticalis(Coleoptera:Coccinellidae)]对竹茎扁蚜[Pseudoregma bambusicola(Homoptera:Hormaphididae)]的最佳捕食密度、最大捕食量、干扰系数、瞬时攻击率、处理时间等参数,研究后斑小瓢虫对竹茎扁蚜的控害潜能,通过后斑小瓢虫生命表的测定,探明利用竹茎扁蚜饲养后斑小瓢虫的种群增长趋势,为开发利用后斑小瓢虫防治竹茎扁蚜提供科学依据。【方法】在温度(23±1)℃,相对湿度70%~73%条件下,采用塑料盒定时定量饲养观察方法测定后斑小瓢虫对竹茎扁蚜的捕食功能,测试后斑小瓢虫自身密度的干扰效应;使用DPS软件,分别用Holling-Ⅱ型、汪世泽Holling-Ⅲ型功能反应新模型和金开正捕食者-猎物功能反应统计模型等昆虫生态学方法进行拟合,分析后斑小瓢虫对竹茎扁蚜的最佳捕食密度、最大捕食量、干扰系数、瞬时攻击率、处理时间等参数,研究后斑小瓢虫对竹茎扁蚜种群的调节作用;通过在林间设置纱网笼罩饲养法测定后斑小瓢虫实验种群生命表,研究后斑小瓢虫内禀增长力等种群数量特征。【结果】在实验室特定条件下,捕食功能反应测定得出后斑小瓢虫3龄幼虫和成虫对竹茎扁蚜平均日捕食量最大可达75头和81头,表明后斑小瓢虫3龄幼虫和成虫对竹茎扁蚜具有较强的捕食能力;后斑小瓢虫自身密度的干扰效应测定结果反映,后斑小瓢虫释放比例为1∶38.8时可以达到最大的控害效能;生命表参数测定结果表明,室内饲养雌成虫的存活率可以达到63%,经过1个世代种群可以增长85.3638倍,在试验温度范围内种群周限增长率(λ)均大于1,后斑小瓢虫在实验室内饲养的种群成几何级数增长。通过生命表参数比较和功能反应模型分析,表明后斑小瓢虫对竹茎扁蚜具有较强的取食及繁殖能力,对竹茎扁蚜种群具有较强的控制能力。【结论】用竹茎扁蚜饲养的后斑小瓢虫种群成几何级数增长;后斑小瓢虫对竹茎扁蚜具有较大的控害潜能。     

从实验种群生命表的参数分析毛竹害螨暴发成灾的成因

研究分析南京裂爪螨、竹裂爪螨、竹缺爪螨在20℃、25℃、32℃温度条件下实验种群生命表，结果表观：温度是影响这三种害螨总产卵量、世代存活率、生殖力以及种群增长指数的重要因素之一。三种害螨的共同天敌竹盲走螨在25℃条件下分别以这三种害螨为猎物的实验种群生命表，并进行比较，结果表明：①竹盲走螨以南京裂爪螨为猎物其净增殖率(Ro=22．35)，内禀增长率(rm=0．155)，周限增长率(λ=1．168)均高于南京裂爪螨(Ro=20．84，rm=0．089，λ=1．094)，而种群倍增时间（t=4．466)低于南京裂爪螨（t=7．704)，因此在林间能有效地控制南京裂爪螨种群的增长；②竹盲走螨以竹裂爪螨为猎物，其净增殖率(Ro=28．35)、内禀增长率(rm=0．152)、周限增长率(λ=1．164)均低于竹裂爪螨（Ro=39．28，rm=0．192，λ=1．212)，而种群倍增时间（t=4．5659)高于竹裂爪螨(t=3．6037)，因此在林间猎物处于高密度时不能完全有效地控制竹裂爪螨种群的增长；③竹盲走螨以竹缺爪螨为猎物，其净生殖率(Ro=21．89)与竹缺爪螨(Ro=21．89)相近，而内禀增长率(rm=0．148)，周限增长率(λ=1．160)低于竹缺爪螨(rm=0．185，λ=1．203)，种群倍增时间(t=4．6753)高于竹缺爪螨(t=3．752)，因此在林间竹缺爪螨密度较高时不能很好地控制竹缺爪螨种群密度的增长。最后从混交林、纯竹林、地面垦复与天敌的关系进行分析，揭示毛竹林近年害螨暴发成灾的成因之一，提出修复的措施。     

大麻二酚的强制降解研究

为建立适用于大麻二酚的含量和杂质检测的高效液相色谱法(HPLC),进行了大麻二酚强制降解研究,对大麻二酚在酸、碱、氧化、高温、高湿和光照条件下的稳定性做了一系列考察,分析其降解趋势,为大麻二酚类药物的制剂处方设计及产品包装储存条件选择提供依据。将大麻二酚置于不同程度的酸、碱、氧化、高温、高湿和光照条件进行了降解实验,用HPLC测定了各降解条件下CBD的含量和降解杂质。实验表明:大麻二酚固体在高温(45℃),高湿(75%RH),光照(4000Lux)条件下分别存放30d均未出现明显降解。在酸性(1mol/L HCl,室温,3h)条件下降解至94.69%,在碱性(0.1mol/L NaOH,室温,3h)条件下降解至91.93%,在氧化(30%H2O2,室温,1d)条件下降解至96.26%。大麻二酚溶液在高温(45℃),高湿(75%RH)条件分别存放30d均未出现明显降解,在光照(4000Lux)条件下存放10d产生大于0.1%的杂质,且该杂质随光照时间延长而增大。大麻二酚类药物的制剂处方设计及产品包装储存条件设定时应避免接触酸、碱及氧化剂。大麻二酚溶液配置后应及时使用并尽量避免光照。     

不同光照时间对欧美杨幼苗生长和光合特性的影响

【目的】研究不同光照时间下欧美杨生长过程中长势及生理适应性,为其优良高光效品种的早期选育及推广栽培提供一定的理论依据。【方法】以16个欧美杨无性系幼苗为研究对象,全遮光条件下,采用LED-100 W全光谱植物生长灯进行人工控光试验,探讨不同光照时间(11、12、13、14和15 h)对欧美杨幼苗生长、生物量、叶绿素相对含量及光合特性等的影响。【结果】1)光照14 h和15 h下幼苗的苗高地径相对增长率、叶生物量显著高于其他光照下(P0.01),而根冠比和叶片SPAD值相对较低,且幼苗光响应曲线走势基本一致,随光合有效辐射(PAR)增加,叶片净光合速率(P_n)先迅速增加,达光饱和点后曲线开始趋于平缓,直角双曲线拟合效果良好(相关系数R~(2 )≥0.948); 2)叶片最大净光合速率(P_(max))随光照时间的延长而增大,其中光照15 h比11 h高104.53%。光照15 h叶片表观量子效率(AQY)、暗呼吸速率(R_d)和光补偿点(LCP)最高,光照14 h光饱和点(LSP)较高,仅次于13 h,而LCP和R_d均低于其他光照时间; 3)叶绿素荧光参数显示,光照11 h幼苗的初始荧光(F_o)最大,最大荧光(F_m)总体差异未达极显著水平(P 0.01),可变荧光(F_v)在光照13 h相对较高。随光照时间延长PSⅡ反应中心原初光能转化效率(F_v/F_m)及潜在光化学活性(F_v/F_o)逐渐增大,且F_v/F_m均在0.83～0.85之间。【结论】随光照时间的延长,欧美杨幼苗的P_(max)、F_m、F_v、F_v/F_o和F_v/F_m均逐渐增大,F_o和根冠比逐渐减小,此外SPAD值、AQY、LSP、LCP和R_d对光照时间也存在不同程度的响应。此结果可作为早期估测欧美杨生长量和生态适应性的参考依据之一,也可作为欧美杨新品种选育、良种推广应用及生产实践过程的重要参考。     

铁皮石斛菌根真菌离体培养条件初探

通过对温度、光照、pH值和碳源等培养条件进行筛选,研究铁皮石斛菌根真菌在不同培养条件下的生长状况。结果表明,铁皮石斛菌根真菌(001)的较佳培养条件为25℃、12 h光照+12 h黑暗、pH6.5、蔗糖、葡萄糖为适宜碳源。     

光周期和温度对美凤蝶滞育诱导的影响

对光周期和温度对美凤蝶峨眉种群滞育诱导的影响进行了研究,结果表明:光周期对美凤蝶滞育的诱导作用与温度有关,在20℃的恒温条件下,光照在12～13 h范围内,随着光照时间的缩短,滞育个体增加,在光照时间短于12.5 h后达到100%;在25℃时,光照时间在11～13.5 h范围内,随光照时间的缩短,滞育率增加,但没有出现全部个体滞育的情况,最高滞育率为94.5%;在30℃时,在实验光周期范围内没有出现滞育个体.温度对滞育的影响受光周期的影响,在相同光照条件下,在一定温度范围内,随着温度的上升,滞育率下降,当温度上升幅度达到30℃,无论长短光照条件下均不出现滞育个体.只有在短光照条件下,低温才有利于滞育,而长光照和高温则有利于个体的发育而抑制滞育产生.短光照对滞育的诱导作用具有累积效应.在20℃恒温条件下,美凤蝶的临界光周期为LD 13 h 11 min:10 h 49 min;而在25℃恒温条件下,美凤蝶的临界光周期为LD 12 h 49 min:11 h 11 min.随着温度的升高,临界光照长度缩短.美凤蝶对光周期的敏感期为5龄幼虫.     

不同发酵条件的白僵菌发酵液对可可毛色二孢的抑制作用

采用菌丝生长速率法测定了不同条件下白僵菌菌株S1-7发酵液对桉树枝枯病菌可可毛色二孢(Lasiodiplodiatheobromae)抑制作用的影响。结果表明,抑菌率最高的培养条件:温度为28℃,培养时间20 d,p H值7.0~8.0,培养基中葡萄糖、蛋白胨、酵母粉含量分别为40、20、20 g/L。此外,60℃以下高温处理发酵液4 h对抑制作用影响不大,温度高于60℃抑菌率显著降低;紫外线照射对发酵液的抑菌率影响不大。     

冻融循环处理对木塑复合材弯曲性能的影响

对两种不同密度的聚丙烯基木塑复合材进行冻融循环处理,研究处理后试件的弯曲性能的变化.研究结果表明：在-29℃～25℃冻融条件下,两种本塑复合材的弯曲性能变化不明显;在-29℃～52℃,-40℃～52℃,-40℃～80 ℃的冻融条件下,两种木塑复合材的弯曲性能随着循环次数增加呈下降趋势;冻融循环处理后,低密度木塑复合材弯曲性能的衰减率要高于高密度的木塑复合材.     

基于生命表技术的胭脂虫适生性研究

运用生命表技术,结合采样测定,对胭脂虫在干热河谷区、南亚热带区及中亚热带区的代表点上的生长情况进行了研究。结果表明：南亚热带地区胭脂虫雌成虫虫体较大,怀卵量较多,质量较大,种群趋势指数最大,为最适生区域;中亚热带区域胭脂虫最大,怀卵量最多,质量最大,但种群趋势指数小,世代历期长,年世代数少,为次适生区域;干热河谷区培育的胭脂虫雌成虫虫体小,怀卵量少,质量小,种群趋势指数较小,为适生区域;在各气候条件下,影响胭脂虫种群数量变动的主导因素为卵的孵化率及1龄若虫或2龄若虫期的强降雨。各试验点均未发现大量胭脂虫天敌。     

Regeneration ecology and population status of a critically endangered and endemic tree species （Ilex khasiana Purk.） in north-eastern India

Detailed studies on population structure and regeneration ecology of Ilex khasiana were carried out at five representative natural populations i.e. Mylliem (Population - I), Upper Shillong (Population - II), Shillong Peak (Population - III), Laitkor (Population - IV) and Nongpiyur (Population - V) to probe into the responsible affecting factors for its population structure and regeneration ability in these populations. Experimental observation under three controlled light conditions (full sunlight (100%), intermediate sunlight (50%) and low sunlight (30%)) showed that the growth status and survival rates of seedlings under intermediate and low light were better than those under the high light condition. The density-diameter distribution in population of adult trees (≥5cm dbh) exhibited a typical character of a regenerating population. A higher seedling mortality rate in natural populations of I. khasiana was most probably due to increase in light intensity following vegetation destruction and other anthropogenic disturbances that cause opening of forest canopy. The findings of the present study would be of immense value in formulating appropriate conservation measures for the species.     

合欢枯萎病菌的生物学特性研究

通过组织分离法获得合欢枯萎病纯茵种，并以常规方法对合欢枯萎病病茵的生物学特性进行了研究，其结果表明，该茵可在PDA、PSA以及合欢的根、茎、叶培养基上生长，在PDA及PSA上的生长情况基本一致，且茵丝旺盛，而在合欢根、茎、叶培养基中的生长情况稍差；该茵的生长温度为5～32℃，最适生长温度为23—29℃；孢子在葡萄糖培养...     

Controlling growth and chemical composition of saplings by iteratively matching nutrient supply to demand: a bootstrap fertilization technique

We developed a fertilization technique that results in the control, and maintenance at defined rates and levels, of growth and tissue composition of plants of different sizes and developmental stages growing at exponential and nonexponential rates in solid media under naturally fluctuating light and temperature regimes. Clonal cottonwood (Populus deltoides Bartr.) saplings were grown in sand. Low concentrations of nutrient solution were added daily at different constant exponentially increasing rates for 20-30 days to produce plants with different growth rates and tissue nutrient composition. Matching nutrient supply to measured growth demand by bootstrapping, where bootstrapping is the use of an iterative equation that calculates demand from either actual or desired growth rates, maintained these differences for 20-40 days. Nutrient additions controlled growth of saplings with growth rates between 2.0 and 4.0% day(-1), heights between 13.9 and 37.5 cm, dry weights between 0.70 and 3.90 g, leaf nitrogen contents between 1.2 and 3.9%, and leaf carbon/nitrogen ratios between 42.1 and 12.5. The technique was reproducible in a greenhouse without temperature, humidity, or light control, and is easily modified to suit different plant species, plants of various sizes, and various growing conditions.     

银杏愈伤组织超低温保存的研究

本文对银杏子叶愈伤组织进行了超低温保存研究。结果表明 ,冰冻保护剂、冷冻速度对解冻后材料相对存活率影响较大 ,冻前预培养和预冻至某一温度停留一段时间也较为重要。在含高浓度山梨醇或甘露醇的培养基上预培养 2d的愈伤组织 ,用 10 %二甲基亚砜 +0 .5mol·L- 1 山梨醇作为冰冻保护剂 ,以 1℃·min- 1 速度降温 ,在 - 15℃、- 35℃分别停留 10min和 30min后 ,投入液氮中保存 1d ,细胞相对存活率可达 6 0 %以上。再培养时 ,细胞能恢复生长。     

Effects of sika deer (Cervus nippon yakushimae) population growth on saplings in an evergreen broad-leaved forest

An increase in size of sika deer populations has caused severe damage to forest vegetation in many regions of Japan. In a Natural World Heritage area on the western part of Yakushima Island, existing high densities of deer are thought to be increasing, but the impact of deer on forest vegetation has not been estimated. Roadside censuses of deer between 1988 and 2006 showed that encounter rates are continuing to increase. Long-term monitoring of individual tree saplings in a 0.13 ha area of the forest between 1992 and 2005 showed that many saplings still remain despite increases in sika deer density. However, differences in growth and mortality rates of preferred, neutral (neither preferred nor avoided) and avoided sika deer food species varied over time. As a group, preferred species continuously had a low growth rate, while their mortality rate increased through time. The growth rates of the neutral and avoided groups decreased especially in the second half of our study period at the same time that their mortality rates increased. These data suggest that in spite of food species preference, direct feeding pressures as well as indirect physical effects by increasing sika deer density are affecting growth and mortality of tree saplings. Clearly, it is difficult to predict how plant communities will respond to possible continued sika deer population growth, and it is therefore important to continue monitoring these forest communities in the interest of preserving the unique ecosystems on Yakushima Island.     

Green spruce aphid infestations cause larger growth reductions to Sitka spruce under shade

Light availability and infestation by the green spruce aphid (Elatobium abietinum) are key factors affecting the growth of Sitka spruce (Picea sitchensis) seedlings under a mature tree canopy, but their combined effect on seedling growth has not previously been quantified. A controlled outdoor experiment in which light levels (high light (HL): 100%, intermediate light (IL): 24%) and aphid infestation (absence/presence) were manipulated was conducted over 2 years to look at the effects on seedling growth and biomass distribution patterns. Aphid population assessments showed a significantly increased population density under IL, with three to four times higher cumulative aphid densities than that under HL. Defoliation rates of infested seedlings were directly related to aphid density. Total seedling biomass was strongly reduced in IL, and aphid infestation caused additional reductions in the biomass of particular components of the seedlings. Dry weight (DW) of older (≥1-year-old) needles in infested trees was significantly decreased in both years. Total root DW at the end of the second year was significantly affected by aphid infestation, and the reduction (14-18%) was similar in IL and HL treatments despite large differences in aphid density. Biomass distribution patterns in infested trees were similar to that of uninfested trees within each light treatment, indicating that the relative decreases in root biomass were accompanied by similar reductions in distribution to the above-ground parts of the seedlings. Leader extension growth of infested seedlings was reduced by 15-17% compared with uninfested seedlings under IL, whereas only a 2-3% reduction in leader extension of infested seedlings under HL was observed. The results showed that the response of seedlings to E. abietinum were primarily dependent on the light environment. The significant reduction caused by aphids on the total DW of older needles and roots, and on leader extension growth, does suggest the potential for effects to accumulate over time.     

白千层组培苗移植技术研究

运用正交试验设计研究组培瓶苗不同炼苗时间、不同基质和不同遮光率的遮阳网对白千层组培瓶苗移植成活率的影响及作用.结果表明,不同炼苗时间和不同基质配比以及不同遮光率的遮阳网对白千层组培瓶苗移植成活率有较显著影响,炼苗时间为15 d,基质采用泥炭土:红心土(3∶1),遮阳网遮光率为60%的设计组合效果最好,成活率达96.3%.     

不同环境因子对落叶女贞种子萌发特性影响的研究

为了给落叶女贞快速繁殖提供理论依据,以落叶女贞种子为试验材料,采用纸上发芽法,研究了不同赤霉素浓度、温度、光照和土壤湿度对落叶女贞种子萌发的影响,结果表明:25℃是落叶女贞种子的最适发芽温度,发芽率达92%,有光时的种子发芽率高于无光时的,但落叶女贞种子在有光和无光时发芽率差异不显著;200mg/L赤霉素处理落叶女贞种子的发芽率最高,达78.56%;在土壤湿度为20%时,落叶女贞种子发芽率最高,达93.52%,萌芽速度最快。