共查询到19条相似文献，搜索用时 203 毫秒
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对插条长度和部位与杨树扦插生根性状和成活率的关系进行了研究。结果表明,不同长度插穗之间成活率有显著差异,插穗长度为16 cm时,生根率最高,为95%;插穗长度为10 cm时,成活率最低,为65%。插条的不同部位对杨树扦插成活率也有显著影响,中部插穗成活率最高,为94%;稍部插穗成活率最低,为63%。
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在临安城区选择居住区、道路、街旁、带状公园、学校、广场六个不同功能区绿地作为研究对象,通过进行负离子浓度、温湿度、光量子、噪声、粉尘以及二氧化碳等指标含量的测定,以此了解各功能区的生态效益状况,结果表明:负离子与粉尘呈显著性正相关(P<0.05)、与湿度呈极显著性正相关(P<0.01),与温度呈极显著性负相关(P<0.01);湿度与温度呈极显著负相关(P<0.01)。城区内负离子浓度苕溪最高,最低的是浙江农林大学东湖校区,苕溪是学校的1.9倍。二氧化碳浓度浙江农林大学东湖校区最高,最低的为城中街,学校是城中街的1.6倍;粉尘含量最高的是人民广场,最低为苕溪,人民广场是苕溪的1.26倍;而噪声最高是人民广场,最低的是浙江农林大学东湖校区。六种功能绿地中,空气负离子含量、噪声大小差异性最显著(P<0.01),二氧化碳、粉尘、光照及湿度差异性较显著(P<0.05),但是空气温度的差异性不显著。
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文章研究了广州城市绿化树种生物同化、吸储、固定C,P,K,SO2,Pb,Cd的环境净化功能,结果表明:研究区域内森林土壤中有机C储量最高达184 t/hm2,最低为24.6t/hm2;TN储量最高达16.7t/hm2,最低为2.0t/hm2;Pb,Cd储量最高分别达837.4kg/hm2、3.9kg/hm2,最低分别为577kg/hm2、1.2kg/hm2;植物叶对SO 2的积累量以高山榕最高,海芒果最低;小叶榕叶吸收固定Pb量最高为22.6g/hm2,尾叶桉叶和白玉兰叶吸收固定C d量最高达0.15g/hm2。
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研究了广州地区城市绿地系统森林植物-土壤系统生物同化、吸储、固定C,P,K,SO2,Pb,Cd的生态效益,结果表明:研究区域内绿地系统土壤中有机C储量最高达184t/hm2,最低为24.6t/hm2;TN储量最高达16.7t/hm2,最低为2.0t/hm2;Pb,Cd储量最高分别达837.4kg/hm2、3.9kg/hm2,最低分别为577kg/hm2、1.2kg/hm2;植物叶对SO2的积累量以高山榕最高,海芒果最低;小叶榕叶吸收固定Pb量最高为22.6g/hm2,尾叶桉叶和白玉兰叶吸收固定Cd量最高达0.15g/hm2。
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应用ArcGIS判读2012年上海的遥感影像,分析上海浦西外环线内建成区(360 km2)树冠覆盖特征;判读样方218个、面积3 420 hm2,占研究区的9.5%。结果表明,现有树冠覆盖总面积为8 241.82 hm2、树冠覆盖率22.89%。浦西建成区内55所公园的平均覆盖率为53.72%;不同功能区的树冠覆盖率有显著差异,其中公园最高(53.72%),其次是外环林带(50.72%)、一般绿地(34.60%)、校园(24.13%),住宅最低(21.87%)。按树冠覆盖估算,研究区共有乔木810万余株,潜在的树冠覆盖率可达24.56%~25.67%,至少可增植乔木60万株。
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为合理规划城市绿地,有益于人们户外活动,研究了不同类型城市绿地空气负离子浓度的日变化,不同类型城市绿地空气负离子浓度、温度、湿度、可吸入颗粒物、氮氧化物、二氧化硫、噪声的差异。结果表明:空气负离子浓度日变化均较明显,不同类型绿地空气负离子浓度、温度、湿度存在显著差异,生物群落越丰富、树龄越大、植被郁闭度越高则空气负离子浓度、湿度越高,温度越低;由枝叶茂盛的高大乔木组成的林地,其空气负离子水平和空气质量较好。空气可吸入颗粒物、氮氧化物、二氧化硫及噪声污染与植被有一定的相关性,相关关系不显著。
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上海绿地群落冠层的UVB屏蔽作用 总被引：3，自引：0，他引：3
文章选择上海绿地典型植物群落类型进行UVB屏蔽效率测定,分析绿地类型、植物配置方式对屏蔽效率的影响作用,并对群落优势种高度、枝下高等特征与群落屏蔽效率相关关系进行了初步研究。研究结果表明:(1)所测定植物群落中UVB屏蔽效率较高的为毛竹群落、水杉群落、香樟群落、女贞群落、朴树群落和雪松群落,UVB屏蔽效率最高为98.4%的女贞群落,最低为17.1%的红叶李群落(2)所测定群落UVB平均屏蔽效率为76.9%,即群落内2m高处UVB辐射值仅为全光照旷地20.2%。(3)植物群落内UVB辐射通量与群落郁闭度呈极显著负相关关系,相关系数为0.749,而与群落优势种平均高度和平均冠幅相关性不显著。
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选择20年生的荸荠种、东魁杨梅和水晶种3个杨梅品种雌株各3株,21年生实生雄优株、21年生荸荠种雌雄同株杨梅和12年生实生东魁雄杨梅进行3a授粉试验,研究杨梅授粉坐果的特性及若干果实性状的花粉直感规律.结果表明:杨梅花粉生活力较强,9d后仍达75.8％以上;杨梅坐果率与花粉生活力不成正比.雄株花粉对坐果率的花粉直感效应明显,即雄株花粉以实生东魁杨梅雄株花粉坐果率最高,平均21.47％;品种以水晶种坐果率最高,平均22.47％;年份以2008年坐果率最高,平均16.43％;雄株花粉与杨梅品种之间存在交互作用.人工授粉与自然授粉的坐果率趋势一致,各品种套袋后人工授粉的坐果率略低于自然授粉,套袋不授粉的不结果.不同雄株对不同杨梅品种成熟期和果实品质(如色泽、果实大小、风味等)的花粉直感现象不明显. 相似文献
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华中五味子是重要的中药材。为给野生华中五味子的引种驯化和开发利用提供参考依据,采用电镜扫描技术、纤维素酶法、TTC法、琼脂固体培养法、授粉比较等试验手段,对河南省伏牛山地区华中五味子两个不同野生雄株的花粉形态、花粉量、花粉生活力、花粉离体萌发特征、授粉特性进行了研究。结果表明:华中五味子两个不同野生雄株的花粉均呈辐射对称状,其外壁均具网状雕纹,与雄株B花粉相比,雄株A花粉的萌发沟长、网眼小而网脊宽;雄株A的单药花粉量高于雄株B;两个雄株的花粉均在散粉24 h后失去活性,且其失去活性的趋势相似,但雄株A的花粉活力在其失活前始终强于雄株B的花粉活力;蔗糖浓度、硼酸浓度对华中五味子两个野生雄株花粉萌发率的影响均达到极显著水平;花粉萌发率,雄株A低于雄株B;雄株A花粉的最适萌发培养基为1%琼脂+0.015%硼酸+10%蔗糖,雄株B花粉的最适萌发培养基为1%琼脂+0.020%硼酸+15%蔗糖;雄株A、雄株B人工授粉的花朵结实率、心皮结实率均高于其自然授粉的结实率;花朵结实率,雄株A高于雄株B;而心皮结实率,雄株A低于雄株B。 相似文献
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Studies on reproductive biology are difficult but useful in species like Aegle marmelos (Linn.) Correa which is of considerable socio-economic importance and possess morphogenetic variation and qualities of wider
adaptability to different soils. Cytology, phenology, pollination, breeding system and natural regeneration of wild and cultivated
trees from India revealed the existence of diploid (2n = 18) and tetraploid trees (2n = 36) in Pachmarhi hills and only diploid
trees in Punjab plains and Shiwalik hills. The diploid and tetraploid trees showed normal meiosis and high pollen fertility.
Phenological events which included leaf fall, leaf emergence, floral bud break, flowering and fruiting are nearly the same
in wild and cultivated trees. Natural pollen transfer in the species was highly efficient. Levels of fruit set following open
pollination was quite high and is reduced considerably following hand pollination probably due to some injury caused to stigma
during experiments. Inspite of synchronous nature of anther dehiscence and stigmatic receptivity, selfing in a flower was
avoided due to herkogamy. Some selfing, however, occurred through geitonogamous mode as bagging of panicles yielded 12.21 ± 0.99
to 14.12 ± 0.91% fruit set. High pollen ovule ratio (9,250–10,600) indicated toward the obligate outbreeding nature. The species
suited to insect and wind mode of pollination. High amount of air borne pollen grains deposited on glycerine smeared glass
microscopic slides suggested towards the wind mode of pollination. Though flowers are dull coloured a variety of insects visited
the flowers due to sweet fragrance and stamen/pollen as food reward. Among insect pollinators, honey bee (Apis dorsata) was the major and legitimate pollinator while the rest were either minor pollinators or mere visitors. Inspite of high fruit/seed
set, natural regeneration through seeds was poor as fallen fruits were destroyed by fungal pathogens and white ants. The species
also propagated vegetatively through coppices and root suckers. It lacks agamospermy as bagging of emasculated flowers yielded
no fruit. It is inferred that ‘bael’ which lacks agamospermy reproduced successfully through gamospermy (xenogamy and geitonogamy)
and vegetative mode (coppices and root suckers). We also concluded that tetraploid trees growing in the Pachmarhi hills with
large sized fruits possessed better potentialities in horticulture if planted through root suckers or coppices. 相似文献
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落叶松种间交配结实力变异和自交衰退的研究 总被引：5，自引：1，他引：5
落叶松种间杂交的结实率普遍较高，但不同种之间有一定差异，其中日本落叶松与兴安落叶松交配结实率最低。种内自由授粉和自交的对比试验显示，示粒种子产生的主要原因是自交。本文讨论了自交不孕无性系的可能利用途径。在不同交配组合下研究了华北落叶松捕捉花粉的过程，确定在传粉期花粉和雌性生殖器官存在一定的相互作用，但无特异性。传粉后约4周，珠心顶端破裂，分泌物进入珠孔道，并与珠被分泌物共同作用于花粉，使花粉向珠心移动。组织化学分析表明，从传粉到受精期间，蛋白质的分布发生区域性变化，传粉期蛋白质几乎分布于整个胚珠，而在受精期则主要集中在颈卵器之上的珠心组织中。初步确定在花粉萌发和受精期，华北落叶松中存在花粉识别与选择系统。 相似文献
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Controlled pollination (CP) is a labour-intensive, but useful procedure applied in tree improvement programmes. However, the
high costs involved and relatively low seed yields often obtained has, in most cases, necessitated the use of lower quality,
open pollinated seed. The aim of the present study was to compare control-pollination methods for combinations among small-flowered
eucalypt species. By making crosses within and among Eucalyptus grandis, E. smithii and E. macarthurii, we compared effectiveness, in terms of seed production and level of genetic contamination, of three CP techniques, namely
emasculation of bagged flowers and subsequent pollination of receptive stigmas (Conventional method), emasculation and immediate
pollination of stigmas with induced receptivity followed by bagging (One Stop Pollination), and pollination of cut styles
without emasculation and bagging (Artificially Induced Protogyny). One tree of each species was used as the female in these
crosses. Although Artificially Induced Protogyny using ripe and semi-ripe buds produced the highest seeds/flower pollinated
in the majority of crosses carried out in this study, the technique, when performed on green buds, resulted in the highest
capsule abortion. Molecular analysis using microsatellite markers also revealed that progeny from the Artificially Induced
Protogyny method, when using green and semi-ripe buds, were highly contaminated by self- and external pollen. Of the three
CP-techniques tested, One Stop Pollination had the lowest genetic contamination. However, this technique also had one of the
lowest seed yields, while the Conventional method was intermediate in performance. 相似文献
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日光节能温室内种植的矮甜李选择授粉方法是获得高产的关键。通过人工点授、自然授粉、室内放蜂、液体授粉 4种方法的对比 ,总结出 4种授粉方法的坐果率为人工点授 (3 1 .0 7% ) >室内放蜂 (2 1 % ) >液体授粉 (9.5 3 % ) >自然授粉 (0 .1 6% ) ,从试验结果看出 ,保护地种植矮甜李必须进行辅助授粉 ,否则无产量。从经济、快捷、简便的角度出发 ,以室内放蜂为最佳授粉方法 ,放蜂量为 1 0 0 0头 /棚。 相似文献
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通过未脱袋去除容器底部、脱袋保留土球、脱袋抖落土球和未脱袋4种栽植方式进行容器苗造林,研究白蜡在晋北地区脱袋造林的效果。结果表明,在晋北地区,脱袋与不脱袋造林对白蜡株高与生物量的影响不显著。但脱袋后白蜡地上部分与地下部分生物量显著提高,根系生长更好。容器袋限制侧根生长,脱袋面积越大,侧根发育越好;保留土球(基质)能够提升地上部分与地下部分联系,促进根系发育,提高苗木抗逆性。因此,在晋北地区种植白蜡宜采用脱袋保留土球的造林方法。 相似文献
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通过对刚竹属3个竹种粉绿竹、黄条早竹、黄槽石绿竹的开花生物学特性及其花粉活力观察及比较,结果表明:在扫描电镜下各竹种间花粉形态比较一致,为球形或近球形,单极孔;外壁纹饰为细颗粒状.花粉活力的测定说明存在不同类型的花粉败育现象.竹子花粉的萌发试验说明竹花粉萌发率普遍较低,最高萌发率为58.7%,最低为21.7%.这些结果也为研究各竹种的不结实和实行人工授粉等研究提供基本的参考依据. 相似文献