核桃楸种群果核形态及地理变异

为揭示核桃楸种群果核形态变异及其与地理环境要素间的关系,以东北到华北天然分布的9个核桃楸种群为研究对象,采用相关、回归和聚类等数据处理方法分析其果核长度、横径、棱径、体积和果形指数.结果显示:不同种群间果核性状均存在极显著差异,且各性状的遗传力均大于0.9,表明核桃楸果核形态性状存在着丰富的变异,且受到很强的遗传控制.在种群间和种群内果核体积的变异系数与相对极差均最大,果核宽度值最小,表明体积的变异最大.相关分析表明,果核形态变异主要受经度、温度和相对湿度的影响.基于果核形态指标9个种群的聚类分析表明,各表型性状并未完全按地理距离而聚类.总的来说,果核性状的变异是核桃楸适应不同生境条件的方式之一,且这种变异是不连续的.     

柏木低效林5种改造措施对土壤动物和土壤理化性质的影响

为了解不同柏木低效林改造措施对土壤生态系统结构与功能的影响,采用随机区组设计方法共设置5种改造措施,即柏木林下种核桃+牧草(草木犀,措施Ⅰ;黑麦草,措施Ⅱ)、核桃+覆盖物(遮阴网,措施Ⅲ;玉米秸秆,措施Ⅳ)、核桃(措施V),研究柏木低效林5种改造措施对土壤动物和土壤理化性质的影响.结果表明:与CK和措施Ⅴ相比,措施Ⅰ-Ⅳ增加(P 0.05)了土壤动物个体密度、类群数,改变了土壤动物群落组成,且措施Ⅳ的土壤动物个体密度、类群数最大;措施Ⅴ对土壤动物个体密度和类群数影响不显著(P 0.05),但改变了土壤动物群落组成;不同改造措施对土壤动物垂直分布的影响略有不同;措施Ⅰ-Ⅱ显著影响了土壤全K含量、容重、田间持水率和总孔隙度,措施Ⅲ显著(P0.05)增加了土壤全K含量,措施Ⅳ显著(P0.05)增加了土壤全N、全K含量和总孔隙度,措施Ⅴ显著(P0.05)降低了土壤有机质含量.可见,柏木林下种核桃+牧草、核桃+覆盖物增加了土壤动物多样性和土壤养分含量,改变了土壤动物群落组成和垂直分布,可能会提高土壤生态系统结构与功能,且柏木林下种核桃+玉米秸秆的效果可能更佳.(图4表5参35)     

不同改造措施对柏木低效林中小型土壤动物群落结构的影响

中小型土壤动物可作为生境质量的重要指示生物。为研究柏木(Cupressus funebris)低效林林窗中种植核桃(Juglans regia)且核桃林下铺设不同覆盖物的生态效应,设置柏木林窗中种植核桃且核桃林下铺设覆盖物〔白膜(HB)、黑膜(HH)、遮阴网(HZ)、凋落物(HD)〕处理、柏木林窗中种植核桃且核桃林下无覆盖(HT)处理和柏木(BM)对照。2013年6月至2014年6月分5次对中小型土壤动物多样性进行调查和比较,中小型土壤动物的分离采用干、湿漏斗法,共获得土壤动物4 893头,隶属2门5纲13类。研究发现,不同改造措施处理中小型土壤动物群落优势、常见、稀有和极稀有类群的组成差异较大,相似性分析发现不同改造措施土壤动物群落结构异质性也较大;柏木林窗中种植核桃且核桃林下铺设覆盖物能显著改善中小型土壤动物群落类群数、个体密度、多样性、均匀度和优势度(P0.05),其中,HD处理的改善效果最佳;同时,柏木林窗中种植核桃且核桃林下铺设覆盖物对柏木低效林中小型土壤动物的空间分布影响较大;柏木林窗中种植核桃且核桃林下铺设覆盖物可改善土壤理化属性,且土壤理化属性间相互作用共同影响土壤动物群落结构;HT处理对土壤全钾、速效钾、有机质含量以及中小型土壤动物空间分布的影响显著(P0.05),但对中小型土壤动物群落类群数、个体密度、多样性、均匀度和优势度的影响不显著(P0.05)。因此,柏木林窗中种植核桃且核桃林下铺设覆盖物可改善柏木低效林中小型土壤动物群落结构,且HD处理对柏木低效林的改善效果最佳。     

川中丘陵区3种林-药复合种植模式土壤呼吸特征

在全球变暖的背景下,陆地生态系统碳循环在大气CO2浓度变化过程中扮演重要角色,而目前大面积推广的林药或农林复合模式在平衡经济发展和维持环境生态的关系中起着举足轻重的作用.2014年1-12月,采用Li-8100对川中丘陵区核桃人工纯林(CK)、核桃-川明参复合模式(HC)、核桃-桔梗复合模式(HJ)、核桃-藿香复合模式(HH)4种林分的土壤呼吸进行定点观测,同时测量土壤温度和湿度.结果发现:各处理土壤呼吸月动态变化呈先增后减趋势,HC最大值出现在6月下旬,而CK、HJ和HH土壤呼吸峰值出现在7月中旬.4种林分最低值都出现在1月,HC、HJ、HH分别是CK的1.36倍、1.61倍和0.89倍.土壤呼吸与土壤温度呈极显著指数增长关系,土壤湿度与土壤呼吸呈倒数关系,但仅HH处理显著.川中丘陵区4种林药模式中,HH模式更有利于减小土壤碳排放.估算各林-药复合模式下土壤呼吸年内总碳排放量大小依次为CK、HJ、HC、HH.本研究表明土壤温度是川中丘陵区土壤呼吸变化的主要因素,不同的人工经营模式对研究区的土壤碳源/汇角色扮演有重要影响.     

三台核桃授粉特性研究

本文研究表明三台核桃可自花授粉、异花授粉、不交自育;花粉传播的水平距离可达350m。     

三台核桃开花的生物学特性

本文观察了三台核桃芽的特性、开花物候期、开花习性、花期分析、落花情况等生物学特性。     

喀斯特特有植物罗甸小米核桃幼苗对光照强度的可塑性响应

研究光照强度对1年生喀斯特特有植物罗甸小米核桃幼苗可塑性的影响,探讨其在个体定居初期如何响应不同光照强度的变化及其生态适应策略.设置约为自然光100％、75％、50％和25％的光照强度处理材料,4个月后收获,比较分析罗甸小米核桃幼苗的形态、生物量分配和生理性状在不同光照强度处理下的差异,并对可塑性指标进行综合评价.结果...     

核桃凋落叶分解对3种作物生长、光合及抗性生理特性的影响

采用盆栽试验,研究了核桃(Juglans regia)凋落叶在土壤中分解对3种受体作物萝卜(Raphanus sativus)、芥菜(Brassica juncea)和白菜(Brasicca pekinensis)生长、光合及抗性生理特性的影响,并比较不同受体作物对核桃凋落叶化感作用的敏感性,筛选可能与核桃套作的作物。试验设置4.5(T1)、9.0(T2)和18.0 g·盆-1(T3)3个凋落叶添加水平,对照(CK)不添加凋落叶。结果表明:(1)核桃凋落叶在其分解过程中对3种受体作物各项生长指标均表现出抑制作用,随着凋落叶量的增加抑制效应逐渐增强,而随着分解时间的延长抑制效应呈减弱趋势;(2)凋落叶分解80 d时,各处理3种受体作物叶片中的叶绿素和类胡萝卜素含量明显低于CK。各植物叶片净光合速率、气孔导度和蒸腾速率均显著低于CK;(3)与CK相比,各凋落叶处理3种受体作物叶片丙二醛含量增加,过氧化物酶和过氧化氢酶活性表现为受抑制作用,而超氧化物歧化酶活性表现为促进作用,可溶性糖含量增加,可溶性蛋白含量降低;(4)3种受体作物对核桃凋落叶化感综合抑制作用的敏感程度由大到小依次为白菜、萝卜和芥菜。综合各项指标可见,核桃凋落叶在分解初期(约80 d时)对3种受体作物产生了强烈的化感作用,主要通过氧化损伤、抑制叶绿素合成和降低其光合能力来阻碍其生长,之后随着凋落叶的进一步分解,释放的化感物质越来越少,对3种受体作物生长的抑制作用减弱。     

核桃青皮提取物的抗菌和抗氧化活性

用不同极性的试剂提取核桃青皮成分,用牛津杯法测定各成分抗菌能力,并从总酚含量、DPPH自由基清除能力、还原能力3个方面测定抗氧化能力.结果显示,核桃青皮不同提取物对不同病源菌有不同的抗菌活性,其中乙酸乙酯提取相和氯仿相对试验细菌的抗菌活性较强,乙酸乙酯相和氯仿相对大肠杆菌、铜绿假单胞菌、枯草芽孢杆菌和金黄色葡萄球菌的抗菌作用MIC分别为6.25/6.25、6.25/1.56、3.13/3.13、6.25/3.13 mg/mL;极性较小的石油醚相对试验真菌有明显抗菌活性,石油醚相对青霉菌、绿霉菌、白色念珠菌的抗菌作用MIC分别为3.13、6.25、6.25 mg/mL;同时,核桃青皮各提取相也有不同程度的抗氧化能力,乙酸乙酯相和氯仿相总酚含量(以没食子酸的相当值GAE表示)、清除自由基能力EC50、还原能力EC50分别为193.52/174.64 mg/g、14.05/26.11μg/mL、34.70/44.60μg/mL,乙酸乙酯相和氯仿相抗氧化能力远远高于其他各相.研究证明核桃青皮提取物有着较好的抗菌和抗氧化活性,具有资源化利用前景.     

3个树种凋落叶水浸提液对三叶鬼针草生长及抗性生理的影响

入侵植物三叶鬼针草(Bidens pilosa)对农业生产、生物多样性和生态系统安全有极大的威胁,利用植物间的化感作用抑制有害植物生长或开发植物源除草剂,是减少化学除草剂对环境负面影响的良好措施。常见树种巨桉(Eucalyptus grandis)、香樟(Cinnamomum camphora)和核桃(Juglans regia)叶片所含次生代谢物质对植物和微生物具有较强的化感潜力,可能会在入侵草本植物的防治上起到重要作用。选用巨桉、香樟和核桃凋落叶,分别制成不同浓度水浸提液,结合培养皿萌发试验和盆栽试验,通过测定三叶鬼针草发芽率、发芽速度、幼苗植株鲜质量、抗氧化酶活性以及渗透调节物质含量,综合评价3个树种凋落叶浸提液的作用效果。巨桉和香樟凋落叶浸提液可显著抑制三叶鬼针草的发芽。三叶鬼针草地上部分鲜质量明显受到高浓度巨桉凋落叶浸提液的抑制,而香樟和核桃凋落叶浸提液的抑制作用微弱;3个树种凋落叶浸提液对三叶鬼针草过氧化物酶(POD)和超氧化物歧化酶(SOD)活性具有促进作用,而对其过氧化氢酶(CAT)活性具有抑制作用;巨桉凋落叶浸提液处理三叶鬼针草抗氧化酶系统表现出"钝化"响应,而其体内丙二醛(MDA)含量则显著增加;对巨桉和香樟凋落叶浸提液而言,三叶鬼针草可溶性蛋白和可溶性糖含量均随浸提液剂量的增加而升高,而在核桃凋落叶浸提液处理下则表现出低促高抑的效应。总体来看,3个树种凋落叶含有干扰三叶鬼针草生长的物质,但效应因树种和浸提液浓度而异。相比较而言,巨桉凋落叶浸提液的综合抑制作用最强,香樟次之,核桃最弱。     

大气中痕量挥发性有机物的结构表征和保留时间的估计与预测

采用分子电性距离矢量（MEDV）表征大气中痕量挥发性有机物的分子结构,同时采用逐步回归结合统计检测对模型进行变量筛选,建立了大气中痕量挥发性有机物定量结构-色谱保留（QSRR）关系的8个变量和5个变量模型,两种QSRR模型的建模计算值复相关系数（R）分别为0.937和0.931;留一法（leave-one-out）交互校验复相关系数（RCV）分别为0.901和0.906,表明模型具有良好的估计能力与稳定性.     

有机物料与~(32)P标记过磷酸钙混合施用对磷有效性的影响

本试验利用~(32)P示踪法研究赤红壤上两种有机物料与过磷酸钙混合施用对磷有效性的影响。盆栽试验表明,纸厂废料蔗渣或猪粪与磷肥混合施用比磷肥单独施用更有利于提高格拉姆柱花草的含磷量和总吸磷量。单位施磷量引起的土壤有效磷和植株吸磷量的增加量也是有机物料单施或与磷肥混施高于磷肥单施。在前39d,~(32)P标记过磷酸钙的利用率在单独施用时为2.14％,比混合施用高一倍左右;在80d时,混合施用的磷利用率较快提高,蔗渣与磷肥混施处理超过单独施用,达22.88％。     

Biosorption and biotransformation of crystal violet by Aeromonas hydrophila DN322p

DN322p, an offspring of Aeromonas hydrophila DN322, has the capacity to adsorb and decolorize triphenylmethane dyes in wastewater simultaneously. As a common triphenylmethane dye, crystal violet (CV) was chosen to test the decolorization characteristics of DN322p. Within 0.5 h, the strain DN322p adsorbed a large amount of CV, producing a deep-colored cell pellet and colorless supernatant. The colors of the cell pellet and supernatant lightened over time. The supernatant and dichloromethane extract of the cell pellet both showed conspicuous CV and leuco CV (LCV) characteristic absorbance peaks at 590 nm and 260 nm, respectively, in the UV-vis spectral analysis. This finding indicated that the DN322p cells can adsorb the two dyes. A 99% (w/w) decolorization rate was achieved within 2.5 h with shaking at 30°C for 50 mg CV·L^?1. High Performance Liquid Chromatography (HPLC) analysis of the dichloromethane extract of the supernatant and cell pellet confirmed that CV was mainly converted into its leuco form. Dead cells had a similar adsorption capacity with living cells. About 90% of CV in the dye solution (50 mg·L^?1) was removed by autoclaved cells with an optical delnsity at 600 nm (OD₆₀₀) above 1.0.     

Coefficient of variation of sea surface temperature (SST) as an indicator of coral bleaching

Coral bleaching has become a major problem on reefs around the world in recent decades. It is believed that mean temperature alone is the primary force driving this ecological phenomenon. We propose that variance in temperature in the short term is just as important as the mean. Thirty years of daily sea surface temperature (SST) data have been collected by the University of Puerto Rico at Mayaguez Marine Laboratory in La Parguera, PR. These data were collated and analyzed initially (by Amos Winter) for their relationship to coral bleaching in this area. We found that the data fell into three categories: high mean temperatures associated with severe bleaching, cooler mean temperatures associated with no bleaching, and years of high SSTs but with no coral bleaching. Here, we examined the relationship between mean temperature during those months in which bleaching occurred, temperature variance (as measured by standard deviation), and coefficient of variation (CV; i.e., SD standardized by the mean). We also derived a critical threshold temperature and level of resolution in time for calculating these statistics to clearly describe the circumstances of bleaching versus non-bleaching events, particularly at marginal bleaching temperatures. These characteristics were compared for the four warmest months of the year (July–October) for four warm bleaching years (1969, 1987, 1990, and 1995), four cool non-bleaching years (1984, 1985, 1986, and 1988), and two warm non-bleaching years (1994 and 2000). No relationship was found between the mean SST and SD in terms of predicting bleaching. The two primary statistics which, in concert, did indicate bleaching, however, were the short-term, biweekly mean temperature and its the associated CV. Bleaching occurs in association with both high temperatures and a high CV. The CV becomes a critical determinant of bleaching only when temperatures are ∼29.1–29.8°C. The warm, non-bleaching years were generally characterized by a CV of < 1.9 and a temperature range between 28.5 and 29.9°C. We conclude that increased mean SSTs alone are not sufficient to induce coral bleaching; a high variance in SST at marginal, lower bleaching temperatures can induce bleaching, and likewise, a low variance of such will not induce bleaching. This variance is most clearly described by the CV.     

A Note on Consistent Estimation of Mean WTP Using a Misspecified Logit Contingent Valuation Model

Monte Carlo evidence has shown that simple, misspecified referendum contingent valuation (CV) models sometimes lead to good estimates of mean willingness to pay (WTP). Empirical studies have found that estimates of mean WTP derived from simple parametric models often differ little from those derived from nonparametric methods. This indicates that simple models can potentially yield WTP estimators that are relatively unbiased. This note shows that very simple logit referendum CV models will estimate mean WTP consistently if the survey bids are drawn randomly from a uniform distribution.     

库布齐沙漠自然植被与人工植被土壤水盐的空间异质性比较研究

干旱半干旱地区土壤水盐的空间分布对土地利用和生态恢复具有重要作用。运用传统统计学和地统计学对库布齐沙漠5种自然植被和5种人工植被0～10和10～20cm深度土壤水分和盐分的空间异质性进行了小尺度比较分析。结果表明：9种群落的土壤水盐平均值下层大于表层,且盐分的空间相关性较水分更高;人工植被土壤水分（CV=5.3%～22.7%）和盐分（CV=15.7%～51.2%）具有空间分布均匀、层间差异不明显等特征,而自然植被水分（CV=9.9%～32.6%）和盐分的（CV=26.9%～180.0%）却与之相反;小尺度上,人工植被土壤不同层间的水分关系、盐分关系以及水盐关系可能随建植时间的增加会越来越不明显,格局强度将不断减弱,这也极有可能改变大尺度上的水盐运移状况,进而影响研究区生态系统的稳定性和安全性。     

Lipid deposition and sexual maturation in cohorts of<Emphasis Type="Italic"> Calanus finmarchicus</Emphasis> (Gunnerus) originating from Bergen (60°N) and Tromsø (69°N) reared in Tromsø, Norway

Two cohorts of Calanus finmarchicus (Gunnerus), with habitats in Bergen (60°N) and Tromsø (69°N), were reared from copepodite stage III (CIII) in mesocosms in Tromsø from April 24 1998 to June 30 1998. The aim was to study whether the two cohorts diverged phenotypically with respect to indication of physiological preparation for diapause as opposed to initiating another generation. At the end of the experiment the fractions of the cohorts that had reached sexual maturation, based on observed stage shifts to adults, was ~45% within the Bergen cohort and ~35% for the Tromsø cohort, within which males appeared before females. Examination of the mandibular gnathobase of copepodites at stage V (CV) revealed that <10% of the Bergen cohort, but >40% of the Tromsø cohort were ready for ecdysis, eventually to become adults in the same year. The physiological expression of the range in individual maturity within the cohorts was revealed in individual carbon and nitrogen content. Both cohorts incorporated the storage lipids wax esters (WE) and triacylglycerols (TAG) rapidly, primarily during CV (0.16–0.21 µg total neutral lipid ind ^-1 day ^-1), with no significant difference. Lipid storage was incorporated from CIII and the maximum was reached at the CV stage. Presumably due to excess food, high WE, TAG and free fatty acid levels were observed in both cohorts. A relative decrease in neutral lipids was observed later in females from both cohorts. We suggest that part of the Bergen population, but also a fraction of the Tromsø population, prepared for diapause in CV. A possible reason for the sexual maturation among the rest of the CV copepodites could be a shift in life "strategy" caused by an unusually high rise in temperature in the mesocosms during the last 10 days of the experiment.