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杨梅根瘤固氮活性和固氮量的评价 总被引：5，自引：0，他引：5
本文对南亚热带山地赤红壤上杨梅幼树根瘤固氮酶活性的日变化和季节变化动态进行了研究。测定了根瘤离体时间对固氮活性的影响。对杨梅年固氮量作出初步评价,7年生杨梅幼树平均结瘤量为51.8g/株,年固氮量为459.8kg/ha,对土壤具有一定的供氮作用。 相似文献
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普通木麻黄抗感青枯病无性系与根瘤固氮活性及生物量关系的研究 总被引：1，自引：0，他引：1
对普通木麻黄不同抗病无性系植株的根瘤固氮活性、结瘤量、植株含氮量及生物量进行了测定。结果表明，抗病性强的无性系植株结瘤量、固氮活性比抗病性差的植株高２一４倍；抗病无性系植株生长高大，生物量和含氮量明显比感病无性系植株高。 相似文献
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施肥对尾叶桉无性系MLA生长影响的研究 总被引：6，自引：3，他引：3
在雷州林业局两个试验点进行了尾叶桉无性系ＭＬＡ施肥试验,林龄３８个月生的结果表明：处理⑥（Ｐ３００ｇ／株＋Ｋ３００ｇ／株＋１５０ｇ／株）的平均蓄积生长量为２９．２４ｍ＾３／ｈｍ＾２．ａ,比处理⑦（常规施肥,滤泥５０００ｇ／株＋Ｐ２５０ｇ／株＋Ｋ１５０ｇ／株）的平均蓄积生长量２６．２６ｍ＾２／ｈｍ＾２．ａ大１１;３％,比ｃｋ（不施肥）的平均蓄积生长量６．３９ｍ＾３／ｈｍ＾２．ａ大３５７．５９％,比总 相似文献
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不同初植密度尾叶桉生长量及经济效益分析 总被引：7，自引：2，他引：5
在雷州半岛的唐家林场设立了尾叶桉５种初植密度：①１ｍ×３ｍ（３３３３株／ｈｍ２）;②１ｍ×４．５ｍ（２２２２株／ｈｍ２）;③２ｍ×３ｍ（１６６７株／ｈｍ２）;④１．５ｍ×４．５ｍ（１４８１株／ｈｍ２）;⑤３ｍ×３ｍ（１１１１株／ｈｍ２）的试验,分别于２年生、３年生和４年生时进行了调查和经济分析。结果表明：⑴尾叶桉初植密度在１１１１～３３３３株／ｈｍ２范围内,林龄４年内,单位面积产量基本上是随着密度的增大而增大,但平均胸径与树高均随着密度的增加而减小。⑵密度３３３３株／ｈｍ２由于株数多,产量最高,利润也最高。⑶从第３年开始,密度１６６７株／ｈｍ２的材积年生长量增幅最大。⑷５种密度的胸径生长的高峰值都出现在前２年;第３年的生长量几乎减少２／３,造林密度越大,减少量越多;至第４年各种密度的年生长量几乎相近。树高生长的高峰值也都出现在前２年,第３年的生长量减少２／３,第４年又减半,至各种密度的树高年生长量几乎相近。除３３３３株／ｈｍ２的材积生长高峰值出现在第２年之外,其它密度的材积峰值都出现在第３年,第４年开始明显减慢。 相似文献
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2,6-二溴-4-硝基苯酚阻燃性能的热动力学研究 总被引：5，自引：0，他引：5
抗流失阻燃剂是当前木材阻燃研究开发的一个重要方向。笔者采用ＴＧ－ＤＴＡ热分析方法研究了２，６－二溴－４－硝基苯酚处理杉木热解过程各阶段的木炭产量和热动力学参数。结果表明：经２，６－二溴－４－硝基苯酚阻燃处理后杉木的产炭率由３１％增加到４５％，炭化阶段的峰温由５４４Ｋ下降到５２４Ｋ，活化能由２７９ｋＪ·ｍｏｌ～（－１）下降到２５６ｋＪ·ｍｏｌ～（－１），热解速率常数由１．２６× １０～（－１９）ｍｉｎ～（－１）增加到６．２３ × １０～（－１８）ｍｏｌ～（－１），淋洗试验的产炭损失率是磷酸氢二铵产炭损失率的１／５。因此，２，６－二溴－４－硝基苯酚不仅对木材具有一定的阻燃作用，同时还具有一定的耐淋洗能力。 相似文献
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固体超强酸催化合成松油醇的研究 总被引：22，自引：7，他引：15
将ＳＯ４＾２－／ＳｎＯ２固体超强酸用于催化合成松油醇，显示出很高的催化活性；获得了ＳＯ４＾２－／ＳｎＯ２制备及松油醇合成的较好工艺条件：硫酸浓度为１．０ｍｏｌ／Ｌ，焙烧温度５５０℃，焙烧时间３ｈ，催化剂用量为松节油重量的８％，一氯乙酸与松节油的摩尔比为１．０￣１．４：１，反应温度６０℃，反应时间８￣１２ｈ。ＳＯ４＾２－／ＳｎＯ２还具有良好的重复使用性能和再生效果。 相似文献
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Inoculation trials were set up in fumigated nursery beds for red alder (Alnus rubra Bong.) bare-root seedling production. Frankia inoculum was applied either as nodule homogenate or as pure culture (strain ArI5). The plots were laid out in 4 blocks of 8 treatments consisting of: control, nodule suspension, and three levels each of cell suspension and cells applied with a peat carrier. Numbers, height, and percentage nodulation on the seedlings were determined at mid-season. Numbers, size, dry weights, and degree of nodulation were determined at lifting. The peat inoculum treatment produced larger seedlings than the other treatments, both at mid-season and at lifting. The other treatments had little effect on growth. Size differences paralleled differences in degree of nodulation. Differences in percentage of seedlings nodulated were most pronounced at midseason, indicating that inoculation confered primarily an early-season advantage. 相似文献
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An investigation was conducted to quantify fine roots and roots nodules over the four seasons in forestry and agroforestry alder (Alnus rubra) stands in North Wales. Soil samples collected in each season were excavated at three sampling points (0.30 m, 0.57 m and 1.00 m distance from the base of each tree) from nine trees of the agroforestry and forestry plots. Result showed that the density of live fine root had significant differences in between seasons and treatments (P ＜ 0.001). The mean weight density of live fine root over the four seasons in agroforestry and forestry was 0.27±0.01 kg·m-3 and 0.54±0.03 kg·m-3, respectively. Weight density of dead root in each system remained constant throughout the year. The mean weight density of dead root was also significantly different (P ＜ 0.01) between forestry and agroforestry systems. Weight density of live and dead root nodule was both constant throughout the year and between the different sampling distances. The mean weight densities of live and dead root nodule over the four seasons were 0.09±0.03 kg·m-3 and 0.05±0.03 kg·m-3 in agroforestry and 0.08±0.02 kg·m-3 and 0.03±0.01 kg·m-3 in the forestry plots, respectively. 相似文献
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固氮豆科树种和豆科树种根瘤菌资源的研究 总被引：13，自引：0，他引：13
调查观察了４８属１２２种豆科树种的结瘤情况，其中８２种结瘤。采用ＶｍｃｅｎｔＪＭ分离方法，从根瘤中分离获得了１２３个根瘤菌株的纯培养，各菌株的菌落特性和生长速度差异明显。经回接和交叉接种试验进一步确定这们为豆科树种根瘤菌。 相似文献
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氮是除水分之外影响干热河谷生物活性的关键因子,豆科植物生物固氮是该地区氮素的重要来源之一。采用乙炔还原法测定了干热河谷不同季节燥红土和变性土林地中大叶相思、新银合欢、木豆和山合欢根瘤固氮酶活性(NAs)。结果表明:新银合欢(16.25μmol.g-1.h-1)和大叶相思(15.85μmol.g-1.h-1)根瘤NAs显著(P<0.001)高于山合欢(9.60μmol.g-1.h-1)和木豆(9.42μmol.g-1.h-1)。雨季根瘤NAs显著高于旱季,约为旱季的2.3倍。燥红土样地上植物根瘤NAs是变性土样地的1.3 1.6倍。研究揭示:除植被类型外,干热河谷植物根瘤NAs主要受土壤类型、季节和土壤含水量的影响,而受土壤温度的影响较小。 相似文献
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红豆树根瘤的形成时间和根瘤的数量与圃地土壤的质量有关,在土壤水肥条件好的环境中,1 a生苗木中的根瘤少见,且根瘤个体极小;在土壤较贫瘠的圃地中,红豆树根瘤十分发达,数量多且形成时间早。红豆树根瘤能够促进苗木生长,有根瘤生长比无根瘤生长的1年生红豆树植株中,根系的干物质增长率46%、根系鲜重的增长率41.9%、茎干物质增长率40.3%、植株总干物质的增长率35.0%、植株总鲜重增长率22.4%、植株叶的干物质增长率14.8%。截根处理有助于根瘤菌感染苗木植株,苗木生长更健壮:截根处理的苗木径高比为4.1%,未截根处理的为3.4%;截根处理促进根系的发育,截根处理的侧根总长度47cm/株、未截根处理的侧根总长度为26cm/株、侧根增加率为80.8%,截根处理的须根总长度228cm/株、未截根处理的侧根总长度为102cm/株、须根增加比率123.5%;截根处理促进苗木根幅的扩大,比未截根处理的根幅增大27.3%。 相似文献
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This study was carried out to assess the relationship of the status of nodulation （i.e., the number of nodules, their shape and size） in root and biomass production of plant growth parameters （i.e., number of leaves, root and shoot lengths, root biomass and shoot biomass） in Albizia saman and Leucaena leucocephala. The assessment started 60 days after seeding. The study revealed that nodulation response and biomass production in both species showed significant dif- ferences over time （p 〈 0.05） in all variables except in the root-shoot ratio （oven-dry） of L. leucocephala. The study also showed significant differences （p 〈 0.05） in nodule formation and biomass production at the end of the study period be- tween the two species except in the number of nodules and leaves and the green root-shoot ratio. There were strong pos- itive correlations between nodule formation and biomass production, i.e., the number of nodules and the age of plants, the number of nodules and leaves, as well as the number of nodules and biomass （root biomass and shoot biomass） in both species. The results obtained using principal component analysis （PCA） and correlation coefficients of the different characteristics of nodulation and biomass production were similar in both species. The PCA showed that shoot biomass （shoot green weight and shoot oven-dry weight） is positively correlated with PC1 （with an eigenvalue of 7.50） and root length is positively correlated with PC2 （with an eigenvalue of 0.19） in the case of A. saman. In the case of L. leucocephala, the PCA revealed that root biomass （root green weight and root oven-dry weight）, shoot biomass and shoot length are also positively correlated with PC1, while nodule formation and the number of leaves are positively correlated with PC2 （with an eigenvalue PC1 of 6.92 and PC2 of 0.49）. 相似文献
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The effects of two pruning regimes on the above-ground biomass allocation and nodulation of Gliricidia sepium (Jacq.) Walp.
(Leguminosae: Robinieae) were studied in a cut-and-carry forage production system under humid tropical conditions in Guadeloupe,
French Antilles. The grass layer composed of a mixture dominated by Paspalum notatum Flügge (80%) and Digitaria decumbens
Stent. The pruning regimes were partial pruning (ca. 50%) every two months and complete pruning every six months. The complete
pruning caused an almost complete turnover of N2 fixing nodules. The nodule biomass decreased after the partial pruning, but
the turnover was not complete. The nodule to foliage biomass ratio followed the same pattern under both treatments, and the
values of the ratio converged towards the end of the experimental period. The maxima of standing nodule biomass were 7.2 and
13.0 kg ha−1 in the partially and completely pruned trees, respectively. The cumulative leaf fodder harvest was higher under
partial pruning management, due to smaller litter loss. The branch biomass production was higher under complete pruning management.
Grass production was not affected by the pruning pattern of G. sepium. It was concluded that the partial pruning management
produces more fodder in the studied association, and the nodulation probably adjusts to the canopy N requirements. The potential
N release to soil in the turnover of nodules of G. sepium (max. 0.82 kg ha−1) is negligible compared to the N export in tree
and grass fodder harvest, 190 and 215 kg ha−1 in partially and completely pruned plots, respectively.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献