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本期报道的主题为树木的保健作用。扬州、佛山都有不同程度的环境污染。有关研究用数字说明树木存在抗污功能,还有许多惊人的发现。如侧柏的抗癌作用,对肺癌细胞NCL-H460抑制率高达97%,山茶的抗污效果明显,山茶叶片中硫累积量为7.551g·kg-1DW,氟的累积量为1.622g·kg-1DW。研究结果为城市居民栽植保健树木提供了科学依据,虽然研究尚处于实验室阶段,但已为居民带来了健康福音。松花江下游的苯污染事件告诉我们根治污染必须采取综合措施。如果我国沿江湖和湿地、工业区、人口稠密区构建完整的抗污森林植物体系,居民室内都放置抗污花草,不乏为根治措施之一。松花江污染事件昭示:我们极力倡导的建设城市森林非常及时、绝对必要,向广大居民宣传城市森林知识不可或缺。下面仅向广大读者再介绍一些解毒植物和土壤及地下水污染的植物净化/矫正材料。
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采集福贡县县城林业土壤,分析了其物理性质和速效养分含量。结果表明,福贡县县城林业土壤密度平均值为1.54g·cm-3,孔隙度平均值为40.12%,速效磷含量平均值为18.63 mg·kg-1,速效钾含量平均值为156.51 mg·kg-1,碱解氮含量平均值为25.73 mg·kg-1。数据表明,福贡县县城林业土壤密度和孔隙度偏低,速效钾和速效磷含量丰富,碱解氮缺乏。
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福州市春季风景林美景度评价及营造建议 总被引：1，自引：0，他引：1
采用综合调查和典型调查相结合的方式,对福州市内代表性的园林绿地春季观赏植物进行调查。重点调查区域包括福州国家森林公园、旗山国家森林公园、南北江滨公园、金牛山公园、福建农林大学中华植物园及校内植物等。调查表明,福州市主要春季观赏植物90种,其中观花植物56种,色叶植物34种。福州市春季观花植物中以木兰科、蔷薇科包含的植物较多,另外还有山茶科、杜鹃花科、大戟科、豆科、冬青科、紫葳科等。采用美景度评判法(Scenic Beauty Estimation,SBE)对福州市春花植物进行评判,得到相应的美景度值。其中具有较高观花价值的亚乔木12种,灌木9种,草本或藤本3种。在调查与评价的基础上,从植物选择和配置2方面初步探讨了福州市春季风景林的营造建议。
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连香树为连香树科连香属,别名子母树。乔木,高可达40m,胸径达1.5 m,树干通直,树皮暗灰色,薄片状剥落。全世界共有三种,我国就有一种,而且数量较少。山西中条山和河南太行山、伏牛山也有零星分布,属国家二级保护植物。
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扬州古运河风光带绿地生态环境效应测试表明:绿地树木对空气微尘有着显著的阻挡、截留和吸滞作用,复层林分的滞尘效应优于园路近20个百分点、优于草坪10.7个百分点。绿地群落可较硬质园路区降低噪音约7dB,可较草坪区降低噪音约4dB;林带减弱噪音的效应与林分组成结构有关,一般以阔叶林减噪效果最显著,叶片大而质硬并重叠排列的树种减噪效果较好,低分枝、矮树冠乔木的减噪作用要比高分枝、高树冠的乔木明显。落叶树种的平均固碳释氧量显著高于常绿树种,且常绿乔木的平均固碳释氧能力是落叶乔木的71%、常绿灌木的平均固碳释氧能力是落叶灌木的67%;不同类型树种的平均固碳释氧能力,总体趋势为:落叶灌木 > 落叶乔木 > 常绿乔木 > 常绿灌木。
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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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Free amino acids and protein in Scots pine seedlings cultivated at different nutrient availabilities
Scots pine (Pinus sylvestris L.) seedlings of a provenance from northern Sweden were cultivated hydroponically for 7 weeks in a climate chamber. The nutrient solution contained either 2.5 (low-N) or 50 (high-N) mg N l(-1) with other essential elements added in a fixed optimal proportion to the nitrogen. After 5 and 7 weeks, the seedlings were analyzed for growth, total nitrogen and other essential nutrients, protein and free amino acids. Low-N seedlings grew more slowly and had higher root/shoot ratios than high-N seedlings. With respect to total nitrogen, the effect of the lower nutrient supply was mainly on the nitrogen content of the whole plant and the allocation of nitrogen among tissues, not on tissue nitrogen concentration. This was also the case for potassium, phosphorus, calcium and magnesium. The proportions by weight among these macronutrients in the whole seedlings were similar in both nutrient regimes. The proportion and concentration of sulfur were significantly lower in low-N seedlings than in high-N seedlings, because of a lower net uptake of sulfur than of other macronutrients. The shoot, needles and stem of low-N seedlings had higher concentrations of free amino acids and lower concentrations of protein than the shoot, needles and stem of high-N seedlings. Arginine dominated the pool of free amino acids in the low-N seedlings, whereas glutamine predominated in the high-N seedlings. We conclude that Scots pine seedlings accumulated soluble nitrogen as arginine when net protein synthesis was limited by factors other than nitrogen availability. Nutritional imbalance, as revealed by growth characteristics and a suboptimal proportion and concentration of sulfur in the seedlings, probably affected synthesis of S-amino acids, resulting in the diversion of assimilated nitrogen to arginine instead of protein. 相似文献
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模拟不同酸雨浓度(pH2.5、4.0、5.6)对杜英幼苗进行喷淋控制实验,研究不同酸梯度条件下杜英幼苗的生长及养分元素含量特征,结果表明:(1)对照组(pH7.0)全株干重约为酸处理组的2倍,酸雨处理对植株生长产生抑制作用,其中对茎部影响最为明显。(2)与pH2.5和pH5.6相比,pH4.0处理组全株干重最大,且根冠比最低,说明植株对pH4.0酸雨有较好的适应性。该处理下,植株体内氮、磷元素含量均较高,钾、镁元素含量在茎中较高,在根中较低。(3)随着酸处理组pH值的降低,植株叶片中钾、硫含量呈明显降低趋势,铁含量呈明显增高趋势;茎中铁含量呈明显增高趋势;根中锌含量呈明显降低趋势。(4)酸雨对杜英幼苗体内硫元素含量有一定的抑制作用,且pH 5.6处理组叶、根中的硫含量显著高于pH 2.5和pH 4.0,即酸雨带来的硫输入在植株体内非但没有出现硫富集现象,反而产生淋失现象。 相似文献
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Geostatistical modeling of the spatial variability of coffee fine roots under Erythrina shade trees and contrasting soil management 总被引：1，自引：0，他引：1
Spatial relationships between root length density of Coffea arabica (coffee RLD) and soil nutrient- related factors at plot scale in a coffee- Erythrina poeppigiana system was studied by geostatistics. In a 24 × 29 m area, (organic and conventional management), coffee and Erythrina fine roots and soil chemical properties were sampled on an irregular grid in the topsoil. A factor analysis explained 83 % of the total variation of the soil attributes. Soil factors were identified: Chemical fertility (CF), Micronutrients, Organic matter, and Acidity (Ac). Based on the spherical model, all the attributes presented a strong spatial structure. The scale of spatial correlation for CF was lesser than for Ac, but similar to coffee RLD. Erythrina RLD had a short-range variation. Patchy areas of high spots of coffee RLD were greater in organic plot. Cross-semivariogram analysis estimated a correlation between soil factors and coffee RLD over a scale of 5.50 m; but 4.23 m with Erythrina RLD. Nutrients linked to P, Zn, exchangeable bases and acidity soil affected the scale of spatial aggregation pattern of coffee RLD. The spatial response of coffee RLD suggests a differential nutrient uptake strategy for acquiring soil nutrients induced by the quality of organic and inorganic fertilizer inputs. The fact that coffee RLD had higher scale of spatial variation than Erythrina RLD and a negative spatial correlation indicate that pruned Erythrina trees are not so competitive for acquiring shared nutrients in an agroforestry system. 相似文献
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运用层次分析法和美景度法对梅州市梅县区景观林带进行综合性评价和美景度评价,结果表明:(1)山杜英(Elaeocarpus sylvestris)、深山含笑(Michelia maudiae)、樟树(Cinnamomum camphora)配置模式的景观效果整齐,鸡冠刺桐(Erythrina crista-galli)、美丽异木棉(Ceiba speciosa)、红花羊蹄甲(Bauhinia blakeana)、樟树配置模式的花色丰富,综合评价较好;山杜英、鸡冠刺桐、美丽异木棉、樟树配置模式的郁闭度低,山杜英、鸡冠刺桐、美丽异木棉配置模式的层次性差,综合评价较差.(2)山杜英、鸡冠刺桐、美丽异木棉和山杜英、深山含笑、樟树配置模式,较受大众喜爱,美景度评价较好;山杜英、鸡冠刺桐、美丽异木棉、樟树和鸡冠刺桐、美丽异木棉、红花羊蹄甲、樟树配置模式,大众喜爱程度低,美景度评价较差. 相似文献
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We studied the effects of excess nitrogen added as nitrate (NO(3) (-)) or ammonium (NH(4) (+)), or both, on mineral nutrition and growth of beech (Fagus sylvatica L.) plants grown at pH 4.2 in Al-free nutrient solution or in solutions containing 0.1 or 1.0 mM AlCl(3). A high external concentration of NH(4) (+) increased the concentration of nitrogen in roots, stems and leaves. The root/shoot dry weight ratio was less in plants grown in the presence of NH(4) (+) than in plants grown in the presence of NO(3) (-). The concentration of phosphorus in the roots was increased and the concentration of potassium in all parts of the plant was decreased by NH(4) (+). A high external concentration of NO(3) (-) caused a decrease in phosphorus concentrations of the root, stem and leaf. Uptake of (45)Ca(2+) by roots was reduced in the presence of high concentrations of NH(4) (+) or NO(3) (-), and a combination of high concentrations of nitrogen and aluminum further reduced the uptake of (45)Ca(2+). Uptake of phosphate ((32)P) and concentrations of phosphorus in root and shoot were increased when plants were grown in the presence of 0.1 mM Al. Exposure to 1.0 mM Al, however, reduced the concentration of phosphorus in roots and shoots and the reduction was greater when plants were grown in the presence of a high external NO(3) (-) concentration. Aluminum binds to roots, and plants grown in the presence of 1.0 mM Al had a slightly higher concentration of aluminum in roots than plants grown in the presence of 0.1 mM Al, whereas the concentration of Al in the shoot was increased 2 to 3 times in plants exposed to 1.0 mm Al. Furthermore, the effects of 1.0 mM Al on uptake of other macronutrients were quite different from the effects of 0.1 mM Al. We conclude that 0.1 mM Al facilitates uptake and transport of phosphorus in beech and that between 0.1 and 1.0 mM Al there is a dramatic change in the effects of Al on uptake and transport of divalent cations and phosphorus. 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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【目的】以雌雄异株山鸡椒为研究材料,分析雌雄植株在生殖生长过程中水分及氮素利用策略的性别特异性动态变化规律,以期为雌雄异株植物资源分配动态变化机制提供理论依据。【方法】测定雌雄植株在开花后105～165天共5个时期叶片养分含量(碳含量、氮含量、碳氮比)、稳定碳同位素组成(δ13C)、稳定氮同位素组成(δ15N),并分析其动态变化规律。【结果】1)雌雄株叶片δ13C平均值分别为-29. 38‰和-28. 08‰。性别和发育时期对雌雄株叶片δ13C值影响均显著,5个时期雌株δ13C值均显著低于雄株;且随发育进程雌雄植株δ13C值均不断下降。2)雌雄株叶片δ15N平均值分别为1. 90‰和2. 95‰。性别和发育时期对雌雄株叶片δ15N值均有极显著影响,开花后105～150天(即雌株果实中精油及柠檬醛含量快速积累期)雌株δ15N值显著低于雄株;随着发育进程,雌雄株叶片δ15N值均表现出双峰变化趋势,双峰出现在开花后105天和135天,雌株叶片δ15N在开花后120天达到最低值,雄株叶片在开花后165天时达到最低值。3)雌雄株叶片碳含量平均值分别为49. 44%和49. 28%。开花后105天和120天,雌株叶片C含量高于雄株叶片C含量,开花后135～165天(果实精油快速积累期到稳定期),雌株叶片C含量低于雄株。雄株叶片C含量随发育进程显著升高,而雌株叶片C含量在不同时期无显著差异。4)雌雄株叶片N含量平均值分别为1. 71%和1. 51%。性别对N含量影响显著,雄株叶片N含量均低于雌株(除开花后135天)。5)雌雄株叶片C/N平均值分别为29. 15和33. 72。性别对叶片碳氮比影响显著,雌株C/N值在不同发育时期均小于雄株,但发育时期对其无显著影响;随着发育时期推进,雄株C/N值下降程度高于雌株。6)雌雄植株叶片δ13C与N含量以及δ13C与δ15N之间均无显著相关性。【结论】山鸡椒雌雄植株在养分含量、水分及氮素利用策略存在差异,且在开花后105～165天表现出动态变化规律。雌株水分利用效率低于雄株,从果实精油及柠檬醛含量快速积累期到稳定期,雌株水分利用效率不断下降;雌株氮利用低于雄株,且随着植株发育,雌雄株叶片氮素利用效率均表现出双峰变化趋势;雄株叶片氮含量低于雌株,分配更多的氮素至花芽以保证花粉形成;果实精油快速积累期到稳定期,雌株叶片碳含量低于雄株,为果实及种子的形成提供更多的碳元素。 相似文献
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《Forest Ecology and Management》1987,18(2):103-112
Uniform nursery stocks of Eucalyptus tereticornis were used to establish an experiment factorially combining site preparation (three levels—bedding; disking; neither bedding nor disking), initial nitrogen applications (two levels—75 g ammonium sulphate per plant; 0 g ammonium sulphate per plant) and initial phosphorus applications (150 g triple super phosphate per plant; 0 g triple super phosphate per plant).Monitoring was carried out for 2 years by which time trees were up to 3.2 m tall and 5.0 cm in diameter at the root collar. Survival at 2 years was significantly higher among plants that had received nitrogen (65%) than those which had not (53%) and among plants on disked or bedded sites (62%) than those on unworked soil (53%). Monthly height increment was briefly, but significantly, increased in plants supplied with additional nitrogen and further enhanced if there was also additional phosphorus. Monthly diameter increment was, over most of the 1st year, significantly greater on sites prepared by bedding; significant increases also resulted, though for more restricted periods, from site preparation by disking and from provision of additional nitrogen. At the end of 1 year significantly higher concentrations of foliar potassium, suggesting enhanced drought hardiness, were detected for plants on bedded or disked ground. The concentration in these was 1%; on unworked ground the corresponding value was 0.8%. Combining bedding or disking with an initial application of nitrogen offset this effect.The short period over which growth benefits from the site preparation and nitrogen application treatments is noted but it is stressed that initial growth encouragement is desirable with Eucalyptus and that overall benefits, as an improved survial, may be long term. The value of phosphorus applications under the prevailing conditions is considered unproven. 相似文献
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Cordero RA 《Tree physiology》1999,19(3):153-163
The hypothesis that the short, stunted development of elfin cloud forest trees is influenced by strong winds was tested by studying growth, gas exchange and biomechanics of potted saplings of Cecropia schreberiana Miq. ex. C. peltata L. (Cecropiaceae) exposed to two natural wind regimes (exposed and protected) at high elevation sites in the Luquillo Experimental Forest, Puerto Rico. The wind-exposure treatment produced several thigmomorphogenetic responses, including reductions in plant stature and crown area, changes in allocation patterns, and increased root to shoot ratio, leaf abrasion and leaf epinasty. Wind-exposure decreased maximum photosynthetic rate and respiration on an area basis, but not on a leaf-mass basis. Wind-exposed plants had lower apparent quantum yields, and higher light compensation points than wind-protected plants. Photosynthetic nitrogen-use efficiency was lower in wind-exposed plants, but such plants had higher leaf nitrogen concentration than wind-protected plants. There were no effects of treatments on stomatal conductance, transpiration rate and water-use efficiency. Stems of wind-exposed plants had lower second moment of area, apparent modulus of elasticity, flexural stiffness and stem density, but higher water content than wind-protected plants. Tissue-density-specific stiffness and the calculated critical height were not affected by the treatments. Wind-exposed plants were biomechanically less predisposed to bending and failing under their own weight than wind-protected plants because their safety factors were smaller, indicating that maintenance of an ontogenetically less developed structure enables plants to cope with wind loading. Windward trees showed a lower scaling component of the allometric relationship between diameter and height than leeward trees. 相似文献
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We studied carbon and nitrogen allocation in mycorrhizal and non-mycorrhizal Scots pine (Pinus sylvestris L.) seedlings grown in a semi-hydroponic system with nitrogen as the growth limiting factor. Three ectomycorrhizal fungi were compared: one pioneer species (Thelephora terrestris Ehrh.: Fr.) and two late-stage fungi (Suillus bovinus (L.: Fr.) O. Kuntze, and Scleroderma citrinum Pers.). By giving all plants in each treatment the same amount of readily available nitrogen, we ensured that the external mycelium could not increase the total nitrogen content of the plants, thereby guaranteeing that any change in carbon or nitrogen partitioning was a direct effect of the mycorrhizal infection itself. Carbon and nitrogen partitioning were measured at an early and a late stage of mycorrhizal development, and at a low and a high N addition rate. Although mycorrhizal seedlings had a higher net assimilation rate and a higher shoot/root ratio than non-mycorrhizal seedlings, they had a lower rate of shoot growth. The high carbon demand of the mycobionts was consistent with the large biomass of external mycelia and the increased belowground respiration of the mycorrhizal plants. The carbon cost to the host was similar for pioneer and late-stage fungi. Above- and belowground partitioning of nitrogen was also affected by mycorrhizal infection. The external mycelia of Scleroderma citrinum retained 32% of the nitrogen supplied to the plants, thus significantly reducing nitrogen assimilation by the host plants and consequently reducing their growth rate. By contrast, the external mycelia of T. terrestris and Suillus bovinus retained less nitrogen than the mycelia of Scleroderma citrinum, hence we attributed the decreased growth rates of their host plants to a carbon drain rather than a nitrogen deficiency. 相似文献