四川野生果树资源种类、地理分布及其开发利用研究

在调查的基础上,结合有关文献和植物标本资料,对四川乡土果树资源的种类、地理分布进行了分析研究。结果表明：四川省有野生果树37科72属825种(含变种、变型和亚种),基本的果实类型有瞢荚果、蒴果、瘦果、坚果、翅果、浆果、柑果、核果、梨果、聚合瘦果、聚合浆果、瘦果类聚花果和核果类聚花果等13种类型;野生果树垂直分布范围在海拔400m～4500m之间,主要集中分布于盆周山地,生境条件严酷的川西北高原区种类最少。此外,还对其开发利用前景进行了分析研究。     

卧龙巴郎山川滇高山栎叶片营养元素的海拔梯度变化特征

本文通过对卧龙自然保护区不同海拔分布梯度上的川滇高山栎不同年龄叶片营养元素含量的研究表明:(1)当年生叶营养元素含量大小排序为NKCaPMg,分别为1.45%、0.75%、0.49%、0.17%和0.13%;N、P含量随海拔呈现先下降后升高的趋势,即在海拔2 400 m和2 800 m较低;K含量随海拔升高而升高;Ca、Mg含量随海拔升高而降低。(2)老叶营养元素含量大小排序为NCaKPMg,分别为1.08%、0.79%、0.40%、0.16%和0.11%;N含量随海拔升高而升高;P、K、Ca、Mg含量呈现先升高后下降的趋势,即在海拔2 400 m和2 800 m较高。(3)N、K、Mg含量呈现当年生叶比老叶高的趋势;P含量除2 600 m以外,老叶的含量比1年生叶低;Ca含量在海拔2 400 m以上出现老叶比1年生叶高,海拔2 000 m为1年生叶比老叶高;(4)N/P比值,当年生叶范围在7.83～9.50,随着海拔的升高而降低;老叶范围在5.25～9.00,具有随着海拔的升高先下降后升高的趋趋势。C/N比值,当年生叶范围在31.91～40.18,老叶范围在44.34～56.04,总趋势为随着海拔的升高而降低。P/K比值,当年生叶范围在0.20～0.28,老叶范围在0.31～0.48;当年生叶随着海拔升高呈现先降低后升高的趋势;老叶随着海拔升高呈现先升高后降低的趋势。K/Ca比值,当年生叶范围在0.83～3.91,老叶范围在0.39～0.65;当年生叶随着海拔的升高而增大,老叶随着海拔升高呈现先升高后降低的趋势。K/Mg比值,当年生叶范围在3.56～10.75,老叶范围在2.50～6.00,总趋势为随着海拔的升高而增大。     

西双版纳兰科植物海拔分布格局

根据实地调查和相关文献资料整理,确定西双版纳野生兰科植物428种。将研究区按200 m海拔段划分为10个海拔梯度,分析兰科植物垂直分布格局。结果表明:①西双版纳兰科植物的垂直分布格局呈"中间膨胀型",峰值出现在1 000~1 200 m海拔段;②相邻海拔段的兰科植物种类相似系数较高(0.31~0.79),海拔段相隔越远相似性系数越小;③随海拔升高各海拔段的兰科植物生活型及区系成分的种类数量也呈现出先升高后下降的垂直分布格局;④地生兰和附生兰的种数在海拔600 m左右达到平衡,600 m以上附生兰占优势;⑤各海拔段兰科植物均以热带种类占主导地位(72%~87.8%),其中又以热带亚洲分布型的种类占优势。     

海拔对陇南市油橄榄开花结实的影响

【目的】以陇南市武都区油橄榄为研究对象,研究了不同海拔(1 093 m,1 136 m,117 5 m和1 213 m)对油橄榄开花结实的影响,为油橄榄在陇南地区的增产与引种提供理论依据。【方法】选取当地3个主栽品种(‘莱星’‘皮削利’‘佛奥’),测定油橄榄植株成花生理指标和果实发育指标。测定的成花生理指标包括叶芽数、花芽数、单枝单位长度花芽数、花序长度及每花序平均花朵数;调查的果实发育指标有坐果率、单果平均鲜重、单株果实总产量和果实体积。【结果】试验区油橄榄花芽数、花芽分化率和每花序平均花朵数随着海拔升高先升高后降低,均在1 175 m达到最大值;与最低海拔1 093 m相比,油橄榄单枝单位长度花芽数在最高海拔1 213 m达到最小值;品种‘莱星’和‘佛奥’的花序长度均在1 175 m为最大,‘皮削利’的花序长度在1 136 m为最大。油橄榄果实坐果率、单果平均鲜果重及单株果实总产量均随着海拔升高也呈先上升后下降的趋势,在1 175 m达到最大;油橄榄果实外形变化不明显,‘莱星’‘佛奥’果实体积在1 175 m达到最大,‘皮削利’果实体积在1 213 m最大。【结论】海拔是影响油橄榄成花及果实发育的一个重要因素,在陇南市武都区白龙江河谷地带种植油橄榄,以1 175 m油橄榄开花结实较好。     

地带性木本植物群落功能型的水热分布格局

植物功能型是对环境条件做出相似的反应和对关键生态学过程具有相似影响的植物组合.不同功能型植物对生态系统过程的作用不同,通过植物功能型的分析对揭示生态系统功能至关重要.甘肃省境内5种地带性木本植物群落(亚热带常绿落叶阔叶林、暖温带落叶阔叶林、温带针阔混交林、寒温性针叶林和荒漠旱生灌木群落)依据植物体的高度、叶片的生长对策及果实类型可划分出23种功能型.其分布格局与水热因子的相关分析表明:1)湿热的生境利于乔木、大灌木、藤木、寄生植物和常绿植物及翅果、坚果、核果、NFDA5NFDA6果、颖果类植物的发育,干冷生境利于灌木、小灌木和落叶植物以及蒴果类植物的发育.2)干果类和肉果类的成因可能与植物生长环境中水分供应状况密切相关,即潮湿的生境利于肉果类植物的发育,干旱的生境有利于干果类(如胞果)的发育.3)研究区域地带性木本植物群落物种丰富度和功能型的丰富度格局主要受制于水分梯度影响,而良好的水热组合可孕育木本植物群落最丰富的果实类型.     

广西核桃优良种质分布情况及坚果品质差异性分析

以81株核桃(Juglans regia)优良种质为研究对象,对广西核桃优良种质的分布情况、表型遗传及内在品质进行测定、分析。结果表明:广西核桃优良种质集中分布在海拔700~1500m云贵高原南部边缘地带及红水河两岸。海拔及温度与核桃品质的相关性分析表明,温度与核桃青皮厚度、核壳厚度、亚油酸及硬脂酸呈负相关,核桃品质与海拔总体呈正相关。对不同海拔之间核桃优良种质的青皮厚度、三径、单果重、出仁率和核壳厚度进行单因素方差分析发现,单果重及青皮厚度皆在海拔300~500m最大,而三径均值则在这个海拔时最低,仅有青皮厚度在不同海拔间差异达到显著。核仁蛋白(21.24%)、亚油酸(63.88%)及硬脂酸(3.91%)含量在海拔1301~1500m达到最高,核仁脂肪(63.03%)与亚麻酸(63.76%)含量都在海拔300~500m达到最高。核仁脂肪含量随海拔上升呈先下降再上升趋势;亚油酸含量随海拔上升呈先下降后上升趋势。不同海拔及年均气温皆会对核桃品质产生一定的影响。     

四川卧龙岷江冷杉天然林生物多样性随海拔梯度的响应

采用典型样带调查法,在卧龙自然保护区邓生阴坡的岷江冷杉天然林内设置不同海拔梯度的样带,分析岷江冷杉天然林的生物多样性随海拔梯度的响应规律。研究结果表明:岷江冷杉天然林乔木和草本植物的物种丰富度、Shannon-Wiener多样性指数、Pielou均匀度指数和均优丰多样性指数随着海拔升高呈下降趋势,而生态优势度指数呈上升趋势;灌木种随着海拔梯度上升物种丰富度下降,Shannon-Wiener多样性指数、Pielou均匀度指数和均优丰多样性指数则呈现出先降低后升高的趋势,生态优势度指数的变化与之相反;群落所有植物的α多样性随海拔梯度的变化规律与乔木层一致。从β多样性变化来看:随着海拔上升,岷江冷杉林内乔木、草本和所有群落所有植物的相异系数CD和Cody指数均呈下降趋势;而灌木层因为物种数和优势种的改变形成β多样性的双峰变化,这与灌木植物的实际分布是相符的。群落整体的物种差异和更替速率受物种数较多的植被类型影响较大,随海拔升高呈逐渐减小趋势。     

晋西黄土高原天然次生林木本植物垂直分布格局

对晋西黄土高原土石山区天然次生林乔灌层优势种组成及其多样性进行了研究,结果表明:木本植物优势种组成受海拔梯度影响明显,丰富度沿海拔梯度升高而呈下降趋势,总体上灌木的丰富度比乔木高,且乔木树种与灌木树种丰富度的变化规律存在明显差异,乔木树种在海拔较高地段丰富度较大,而灌木树种则是在海拔较低地段丰富度较大;乔木层α多样性指数随海拔升高而递增,而灌木层α多样性指数则随海拔升高呈缓慢下降趋势.采用Cody指数和Whittaker指数计算了各海拔群落的β多样性指数,得出各海拔群落的β多样性指数多以相邻海拔群落的指数值最小,群落间海拔差异越大指数值越大,其中在海拔高度1 650 m左右β多样性指数变化最为显著.     

青海云杉林生物量及地上径向密度随海拔的变化特征

以祁连山乔木建群种青海云杉(Picea crassifolia)为研究对象,通过野外调查取样和室内试验分析,研究了青海云杉林分因子、生物量及地上径向密度沿海拔梯度的变化特征,为探索祁连山水源涵养功能提供科学依据。结果表明:树高随着海拔的升高呈现先增加后减小的趋势,2 800 m处树高最大,2 900 m处树高最小,平均胸径随着海拔的升高呈现递增的趋势,3 100 m处胸径最大,2 700 m处胸径最小;林分密度随着海拔的升高呈现递减趋势,2 700 m处林分密度最大,3 100 m处林分密度最小。各海拔区段树高和平均胸径差异不显著,各海拔区段林分密度差异显著。青海云杉地上生物量随着海拔的升高呈现先减小再增大的趋势,海拔2 900 m的青海云杉地上生物量最少,地下生物量随着海拔的升高先减小再增大,变化幅度较为平缓,海拔3 100 m地下生物量最大。地上径向密度随着海拔的升高呈现先减小后增大的变化趋势,海拔3 100 m地上径向密度最大,海拔2 800 m地上径向密度最小;海拔3 100 m是青海云杉的最佳生长海拔区段,最能反应森林水源涵养能力的强弱。     

地带性木本植物群落功能型的水热分布格局

植物功能型是对环境条件做出相似的反应和对关键生态学过程具有相似影响的植物组合。不同功能型植物对生态系统过程的作用不同 ,通过植物功能型的分析对揭示生态系统功能至关重要。甘肃省境内 5种地带性木本植物群落 (亚热带常绿落叶阔叶林、暖温带落叶阔叶林、温带针阔混交林、寒温性针叶林和荒漠旱生灌木群落 )依据植物体的高度、叶片的生长对策及果实类型可划分出 2 3种功能型。其分布格局与水热因子的相关分析表明 :1)湿热的生境利于乔木、大灌木、藤木、寄生植物和常绿植物及翅果、坚果、核果、果、颖果类植物的发育 ,干冷生境利于灌木、小灌木和落叶植物以及蒴果类植物的发育。 2 )干果类和肉果类的成因可能与植物生长环境中水分供应状况密切相关 ,即潮湿的生境利于肉果类植物的发育 ,干旱的生境有利于干果类 (如胞果 )的发育。 3)研究区域地带性木本植物群落物种丰富度和功能型的丰富度格局主要受制于水分梯度影响 ,而良好的水热组合可孕育木本植物群落最丰富的果实类型。     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.