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1.
垂柳广泛用于城乡绿化的池塘、道路、公园、河提绿化,形成的景观效果较好,很受人们的喜爱。为满足城乡绿化市场对大规格垂柳的需求,快速培育干形通直、健壮、无病虫害大规格苗木是苗木培育需要解决的生产实际问题,在应用实践中对垂柳的扦插育苗、栽培管理技术及应用经验进行总结,做好扦插育苗苗圃的水肥管理、松土除草、病虫害防治、摸芽等技术是缩短培育周期的关键。  相似文献   

2.
镉在土壤-金丝垂柳系统中的迁移特征   总被引:2,自引:0,他引:2  
张雯  魏虹  孙晓灿  顾艳文 《生态学报》2013,33(19):6147-6153
以金丝垂柳为试验对象,采用盆栽试验方式,设置无植物和金丝垂柳两组试验,分别对两组试验的土壤做梯度浓度Cd处理:0(无镉处理)、2(低浓度处理)、20(中浓度处理)、80(高浓度处理) mg/kg 土壤干重,无植物组各处理分别定义为CK(无镉处理)、L(低浓度处理)、M(中浓度处理)、H(高浓度处理),金丝垂柳组各处理分别定义为CKP(无镉处理)、LP(低浓度处理)、MP(中浓度处理)、HP(高浓度处理)。通过对土壤中各形态Cd含量及金丝垂柳叶、韧皮部、木质部、根部的Cd含量测定,分析了金丝垂柳及不同浓度Cd处理对土壤中中性交换态、螯合态和残渣态Cd含量的影响,并评价了富集指数(BCF)、转移系数(TF)和生物有效性(BF),明确了Cd在土壤-金丝垂柳系统中的转移特征及金丝垂柳对土壤中Cd的清除效果。结果表明:(1)金丝垂柳对土壤中中性交换态、有效态Cd含量及总Cd量的降低具有极显著影响,HP组与无植物H组相比,中性交换态及有效态Cd含量分别降低了52.73%、25.34%,MP、HP组与对应的无植物处理组的总Cd量相比分别降低了11.33%、13.89%;(2)金丝垂柳各处理组的Cd积累量随Cd处理浓度的增加和处理时间的延长而增加,处理90 d后,HP处理中木质部和根部的Cd含量可达170.64 mg/kg、212.49 mg/kg;(3)各浓度Cd处理下,金丝垂柳各部位生物富集系数呈根>木质部>韧皮部、叶,且随着Cd处理浓度的增加而显著降低,随处理时间的延长而升高;与40 d相比,90 d时LP组叶的生物富集系数增加了6.90倍,增幅最大。(4)各部分转移系数均随处理时间的延长而降低,90 d时LP、MP的转移系数分别比40 d时的结果低47.94%、41.34%。(5)金丝垂柳LP、HP组土壤Cd的生物有效性显著低于相应的无植物处理L、H组,分别低70.73%、88.46%,MP组与M组无显著差异。研究结果表明,金丝垂柳能有效地吸收土壤中的有效态Cd,降低土壤中Cd的生物有效性及总Cd量,提高土壤的安全性,并能将吸收的Cd有效地转移至地上部分,尤其是木质部储存。随着植株不断生长,生物量的增加,金丝垂柳可有效地清除土壤中的Cd,适用于对Cd污染地区进行长期植物修复。  相似文献   

3.
以侧柏(Platycladus orientalis)和垂柳(Salix babylonica)为研究对象,采用动态顶空套袋采集法和自动热脱附-气相色谱/质谱联用技术来分析这些植物释放的挥发性有机物(VOCs)的组成和释放模式。选择不同的时间和天气条件下的样本进行采集,并记录相关信息。通过对原始数据的分析,确定有益挥发性有机物(BVOCs)的成分和相对百分含量。研究结果显示,侧柏和垂柳在不同季节释放的BVOCs成分主要包括醇类、醛类、烯烃类等其他类化合物,这些有益BVOCs在植物的生理和生态功能中扮演着重要的角色,对于深入了解植物与环境之间的相互作用具有重要意义。侧柏和垂柳释放BVOCs成分在不同季节会有所变化。其次,研究分析了侧柏和垂柳在不同季节中有益BVOCs成分的含量和变动趋势。侧柏在不同季节的释放模式呈现出明显的差异。春季的释放模式呈现出“单峰单谷”曲线,夏季的释放模式呈现出“单峰”曲线,而秋季的释放模式呈现出“双峰单谷”曲线。这表明侧柏在不同季节中的挥发物释放存在明显的季节性变化。相比之下,垂柳的释放模式在不同季节中相对稳定,呈现出一致的“单峰型”曲线。这说明垂柳的挥发物释放...  相似文献   

4.
【目的】考察星天牛Anoplophora chinensis对不同生理状态青皮垂柳Salix ohsidare挥发物的选择偏好性,深入探究星天牛对虫害青皮垂柳与健康青皮垂柳行为选择差异的原因。【方法】利用动态顶空吸附法,分别收集虫害和健康两种生理状态下的青皮垂柳枝条挥发物,通过气相色谱 质谱联用仪(GC-MS)对收集的挥发物样品进行鉴定与分析,采用触角电位仪(EAG)和Y型嗅觉仪分别分析星天牛对挥发物样品中鉴定的主要化合物的标准化合物的电生理以及行为反应,通过大笼行为实验和林间诱捕试验分析单一挥发性化合物及其双组分和三组分配方对星天牛成虫的诱捕效果。【结果】健康青皮垂柳枝条挥发物中共鉴定出3种主要化合物,包括α-蒎烯、3-蒈烯和樟脑,而虫害青皮垂柳枝条挥发物中鉴定出5种主要化合物包括α-蒎烯、β-蒎烯、3-蒈烯、β-罗勒烯和樟脑。另外虫害青皮垂柳枝条挥发物中的樟脑含量显著高于健康青皮垂柳枝条中的,3-蒈烯在两种挥发物中含量差异不显著,而健康青皮垂柳枝条挥发物中的α-蒎烯含量显著高于虫害青皮垂柳枝条中的。EAG实验表明,星天牛成虫对α-蒎烯、3-蒈烯和β-罗勒烯3种化合物的EAG反应相对值较高,并且随这3个化合物浓度的升高而逐渐增大;星天牛成虫对β-蒎烯和樟脑的EAG反应相对值差异不大,且这2个化合物浓度变化对EAG反应相对值无明显影响。Y型嗅觉仪实验表明,在1 mg/mL浓度下,α-蒎烯、3-蒈烯和β-罗勒烯吸引星天牛雄成虫数量均显著高于对照组(石蜡油),β-罗勒烯吸引的星天牛雌成虫数量显著高于对照组;在10 mg/mL浓度下,3-蒈烯吸引的星天牛雄成虫数量显著高于对照组。大笼行为实验表明,三组分虫害配方D(α-蒎烯∶3-蒈烯∶β-罗勒烯=42∶30∶103)、α-蒎烯和β-罗勒烯吸引的星天牛成虫数量最多,显著高于双组分健康配方H(α-蒎烯∶3-蒈烯=105∶38)和3-蒈烯吸引的成虫数量。林间诱捕试验表明,α-蒎烯和虫害配方D对星天牛成虫的诱捕效果最好,诱捕的成虫数显著高于β-罗勒烯和健康配方H诱捕的成虫数,而3-蒈烯和空白对照组没有诱捕到星天牛成虫。【结论】虫害和健康青皮垂柳枝条挥发物中共有的α-蒎烯和虫害青皮垂柳枝条挥发物中特有的β-罗勒烯是对星天牛成虫具有引诱作用的两种重要寄主植物挥发性化合物,而3-蒈烯抑制了α-蒎烯对星天牛成虫的引诱作用。我们推测,虫害青皮垂柳挥发物中特有的β 罗勒烯是造成虫害青皮垂柳比健康青皮垂柳更容易受到星天牛危害的原因之一。  相似文献   

5.
垂柳雌花蜜腺一枚,位于于房与花序轴之间,多呈扁平广卵形,由分泌表皮、泌蜜组织和维管束组成。雄花蜜腺呈基部相连的两枚突起,一枚位于花丝与花序轴之间,基部宽扁,上部棒状;另一枚位于花丝与苞片之间,棒状,仅由分泌表皮和泌蜜组织组成。雌、雄花蜜腺均起源于花托表面2—3层细胞。在蜜腺发育过程中,雌、雄花蜜腺泌蜜组织细胞的液泡发生规律性变化.雌花蜜腺为淀粉型蜜腺,而雄花蜜腺为非淀粉型蜜腺。雌、雄花蜜腺的原宜汁分别由蜜腺维管束韧应部或花丝维管束韧皮部提供,其蜜计最后均由分泌表皮细胞和变态气孔排出。  相似文献   

6.
为探讨垂柳(Salix babylonica)对苯酚污染物的耐受程度及其应用于苯酚污染环境修复的可行性,了解苯酚胁迫对垂柳光合作用生理过程的影响与限制机理,采用水培模拟胁迫实验方法,在5种苯酚溶液浓度(50、100、200、400和800mg·L–1)下,测定垂柳植株叶片光合气体交换及叶绿素荧光参数。结果表明,苯酚对垂柳光合作用具有显著的抑制作用,表现为叶片净光合速率(Pn)、最大光合速率(Pnmax)、光合量子效率(Φ)、PSII最大和实际光化学效率(Fv/Fm和ФPSII)等均明显下降。苯酚胁迫浓度越高,对垂柳光合作用的抑制程度越大;苯酚胁迫限制光合作用主要由非气孔因素引起。将垂柳用于苯酚污染的水体环境修复时,苯酚浓度应在200 mg·L–1以下,否则垂柳的光合作用效能会明显降低。垂柳光合作用生理活性耐受苯酚胁迫的极限浓度还需进一步实验研究。  相似文献   

7.
苏柳172和垂柳对Cu2+的吸收特性及有机酸影响   总被引:1,自引:0,他引:1  
采用溶液培养的方法,研究了苏柳172和垂柳对Cu2+吸收的动力学特性及低分子量有机酸(乙酸和苹果酸)对Cu2+吸收的影响。结果表明:苏柳172和垂柳根系对Cu2+的吸收量随溶液Cu2+浓度的升高及吸收时间的延长而增加。苏柳172和垂柳对Cu2+吸收的浓度动力学曲线呈线性,非饱和曲线,可以用米氏方程很好地拟合。米氏方程拟合的结果说明,垂柳根系的Cu2+吸收能力要稍强于苏柳172。Cu2+浓度为20 μmol/L时,随着乙酸和苹果酸浓度的增加,对苏柳172和垂柳根系吸收Cu2+的促进作用呈先上升后下降的趋势,其中,乙酸在10:1(乙酸∶ Cu2+)、苹果酸在5:1(苹果酸∶ Cu2+)时促进作用最强。Cu2+在根尖区的含量远远大于成熟区,说明根尖区是吸收Cu2+最活跃的区域。在Cu2+浓度为20 μmol/L的吸收液中加入乙酸或苹果酸(有机酸∶ Cu2+= 10:1)时,苏柳172根尖区的Cu2+含量分别增加了16.5%和33.7%,根成熟区的Cu2+含量增加了23.7%和43.0%,但根尖区和成熟区的Cu2+含量比值分别是1.40 和1.39,略小于不加有机酸时的1.49。乙酸与Cu2+的比例为10:1时,当Cu2+浓度小于20 μmol/L时乙酸促进垂柳根系对Cu2+的吸收,当Cu2+浓度大于20 μmol/L时,乙酸抑制垂柳根系对Cu2+的吸收,抑制作用随Cu2+浓度的升高而加强,说明低浓度的乙酸可以促进垂柳根对Cu2+的吸收,而高浓度的乙酸能够抑制垂柳根吸收Cu2+。同时,乙酸抑制了Cu2+在垂柳地上部的积累,抑制作用随着Cu2+浓度的增加而加强,说明乙酸能够抑制Cu2+由根向地上部的运输。  相似文献   

8.
采用盆栽试验的方法,研究土壤中不同浓度的镉(0、2、20、80 mg·kg-1)胁迫条件对金丝垂柳幼苗的生长、净光合速率(Pn)、光合色素含量及叶绿素荧光参数(Fv/Fm、φPsⅡ和qP)的影响.结果表明:(1)2 mg·kg-1处理组植物的生长、净光合速率及叶绿素荧光参数随着处理时间的增加呈先下降后上升的趋势,说明2...  相似文献   

9.
研究了CO_2浓度倍增对垂柳(Salix babylonica L.)和杜仲(Eucommia ulmoides Oliv.)叶片光合色素含量、叶绿体对光能吸收能力和激发能在两个光系统之间分配的影响。结果表明,CO_2 浓度倍增能提高垂柳叶片单位鲜重和单位叶面积叶绿素(Chl)和类胡萝卜素(Car)的含量;提高杜仲Chl含量,降低Car含量。CO_2浓度倍增能提高含等量Chl的叶绿体对光能的吸收和激发能在两个光系统间分配的调节能力。  相似文献   

10.
不同秸秆填埋量对盐碱土水盐运移及垂柳反射光谱的影响   总被引:1,自引:0,他引:1  
乔雪涛  何欣燕  何俊  范秀华 《生态学报》2018,38(22):8107-8117
在宁夏西北盐化生态脆弱区的典型盐碱化土地,通过随机区组试验,探究在栽植穴填埋秸秆2000(T_1)、7000(T_2)、12000kg/hm~2(T_3)及17000 kg/hm~2(T_4)等作隔盐层对土壤水盐运移及垂柳(Salix babylonica)反射光谱的影响,将地下土壤水盐变化与地上植物生长及生理状况相结合,以期更准确的反映出各处理对盐碱土壤改良效果及地上植被恢复情况。研究结果表明:(1)填埋一定量的秸秆作隔盐垫层可以改变地下土壤水盐的剖面分布特征。T_2、T_3和T_4处理与对照组相比,20—80 cm土层土壤含水量都显著提高,填埋的秸秆层起到了蓄水保墒的作用;都明显降低了0—80 cm土层土壤盐分含量和盐溶质浓度;但这3种处理之间无显著差别。T_1由于填埋秸秆量过少,无显著蓄水控盐效果。(2)通过检测植物叶片反射光谱可以反映出地上植物生长及生理状况的变化。填埋一定量的秸秆作为隔盐垫层有助于改善垂柳的生理状况。T_2的垂柳叶片光合色素含量最高,光合特性及营养状况最好,其他光谱参数结果都显著提高。T_3显著提高叶绿素含量和光合特性,但效果均不如T_2,且营养状况差。T_4处理类胡萝卜素含量与叶片水分含量均处于最高水平,但叶绿素含量、营养状态以及光合特性都显著降低。T_1处理效果最差。(3)在地下填埋秸秆作隔盐层,会通过对地下土壤水盐运移及微域生态系统环境的调节,影响到地上植物生长及生理状况。综合地下水盐分布与地上植物叶片反射光谱的结果,T_2是宁夏引黄灌区盐碱地改良中最适宜的秸秆填埋量。  相似文献   

11.
High incidence (up to 40%) of symptoms of yellowing and yellow mottling was observed in 5–8 years old orchards of kinnow mandarin {Citrus reticulate Balanco (‘King’ × ‘Willow mandarin’)} in the Punjab state of India during a survey in January 2007. These symptoms are often confused with nutrient deficiency and other stress related disorders. However, a greening bacterium has been attributed to cause the disease. The disease was graft transmissible and sequencing of 16S rRNA, 16S/23S intergenic spacer region and 23S rRNA of the greening bacterium associated with yellowing disease in kinnow mandarin confirmed it to be Candidatus Liberibacter asiaticus (‘Ca L. asiaticus’) showing maximum identity of 95.9% with ‘Ca L. asiaticus’ from USA and Brazil in 16S rRNA. The study indicates definite association of ‘Ca L. asiaticus’ with yellowing/chlorotic mottling symptoms of greening disease of kinnow mandarin in Punjab state of India.  相似文献   

12.
According to the nutrient-translocation hypothesis, yellowing tree leaves are colonized by aphids at the end of the growing season owing to improved availability of nutrients in the phloem sap after chlorophyll degradation. We measured aphid densities on potted Betula pendula seedlings in a field site where a small proportion of foliage rapidly turned yellow before normal autumn coloration as a consequence of root anoxia. The number of adults and nymphs of the birch-feeding specialist aphids Euceraphis betulae, Betulaphis brevipilosa and Callipterinella tuberculata were counted from leaves on each of the 222 plants. Aphids were detected on 19 per cent of green leaves and on 41 per cent of yellow leaves. There was no indication of aphid avoidance of yellow leaves, and the number of winged (alate) viviparous E. betulae adults and their nymphs were significantly higher on yellow leaves than on green leaves, while the numbers of apterous B. brevipilosa and C. tuberculata did not differ between the leaf colour types. Our result suggests that only aphid species with alate generation during colour change can take advantage of yellowing leaves. This may explain the exceptional abundance of E. betulae compared with other aphid species on birches.  相似文献   

13.
Euphrasia brevilabris Y. F. Wang, Y. S. Lian & G. Z. Du, a new species of the Scrophulariaceae from Gannan grassland of Gansu belonging to the east edge of the Qinghai-Tibetan Plateau of China, is described and illustrated. It is related to E. regelii Wettst. by having dense tentacle on the leaves, bracts and calyces, but differs from plant shorter, 3–7 cm high, without ramification, leaves smaller, 3–5 mm long, corolla yellow, the back 3–5 mm long, and labium shorter than muffle. It is also similar to E. pectinata Ten. by bracts obviously bigger than vegetative leaves, but differs from plant shorter, leaves smaller, having dense tentacle on the leaves, bracts and calyces, corolla yellow, labium shorter than muffle.  相似文献   

14.
Phormium yellow leaf (PYL) phytoplasma causes a lethal disease of the monocotyledon, New Zealand flax (Phormium tenax). The 16S rRNA genes of PYL phytoplasma were amplified from infected flax by PCR and cloned, and the nucleotide sequences were determined. DNA sequencing and Southern hybridization analysis of genomic DNA indicated the presence of two copies of the 16S rRNA gene. The two 16S rRNA genes exhibited sequence heterogeneity in 4 nucleotide positions and could be distinguished by the restriction enzymes BpmI and BsrI. This is the first record in which sequence heterogeneity in the 16S rRNA genes of a phytoplasma has been determined by sequence analysis. A phylogenetic tree based on 16S rRNA gene sequences showed that PYL phytoplasma is most closely related to the stolbur and German grapevine yellows phytoplasmas, which form the stolbur subgroup of the aster yellows group. This phylogenetic position of PYL phytoplasma was supported by 16S/23S spacer region sequence data.  相似文献   

15.
Melia azedarach var. japonica trees with leaf yellowing, small leaves and witches' broom were observed for the first time in Korea. A phytoplasma from the symptomatic leaves was identified based on the 16Sr DNA sequence as a member of aster yellows group, ribosomal subgroup 16SrI‐B. Sequence analyses of more variable regions such as 16S–23S intergenic spacer region, secY gene, ribosomal protein (rp) operon and tuf gene showed 99.5?100% nucleotide identity to several GenBank sequences of group 16SrI phytoplasmas. Phylogenetic analysis confirmed that the Melia azedarach witches' broom phytoplasma belongs to aster yellows group.  相似文献   

16.
A novel yellow-leaved cultivar of tropical tree was characterized with morphological, histochemical and biochemical analysis.Ficus microcarpa L. f. cv. Golden Leaf shows characteristic golden (yellow) leaves as well as normal green leaves under the subtropical field condition. Except the appearance of the yellow leaves, morphological characteristics of Golden Leaf agreed to those of wild-type. The yellow leaves of Golden Leaf contained low amount of chlorophyll (8%) and carotenoid (26%), whereas flavonoid level was 5-fold higher than that of wild-type. TLC of hydrolysate of the methanol-extract showed the increase of two flavonols in the yellow leaves. Fluorescence from leaf transverse section indicated that those changes in pigment contents took place in mesophyll cells. Despite low content of photosynthetic pigments the yellow leaves involved the comparable amount of Rubisco subunits to wild-type. The reduced chlorophyll content of the yellow leaves was restored by shading them from high-light but the UV-shading did not alter the pigment content. Those characteristics of the yellow leaves were not observed in the green leaves of Golden Leaf. Results suggest that Golden Leaf is attributed to a chloroplast mutant ofF. microcarpa that is sensitive to continuous high-light irradiation. The mechanism of the leaf-goldenning (yellowing) is discussed in relation to high-light stress and to leaf-senescence.  相似文献   

17.
The maturation of ribosomal RNAs (rRNAs) is an important but incompletely understood process required for rRNAs to become functional. In order to determine the enzymes responsible for initiating 3' end maturation of 23S rRNA in Escherichia coli, we analyzed a number of strains lacking different combinations of 3' to 5' exo-RNases. Through these analyses, we identified RNase PH as a key effector of 3' end maturation. Further analysis of the processing reaction revealed that the 23S rRNA precursor contains a CC dinucleotide sequence that prevents maturation from being performed by RNase T instead. Mutation of this dinucleotide resulted in a growth defect, suggesting a strategic significance for this RNase T stalling sequence to prevent premature processing by RNase T. To further explore the roles of RNase PH and RNase T in RNA processing, we identified a subset of transfer RNAs (tRNAs) that contain an RNase T stall sequence, and showed that RNase PH activity is particularly important to process these tRNAs. Overall, the results obtained point to a key role of RNase PH in 23S rRNA processing and to an interplay between this enzyme and RNase T in the processing of different species of RNA molecules in the cell.  相似文献   

18.
The present paper deals with the status of manganese (Mn) in rubber trees on 110 rubber plantation at 46 counties in the rubber tree growing regions of China. The content of Mn in rubber tree leaves ranges from 31 to 2167 ppm, averaging 390 ppm which is higher than that in the leaves of normal rubber trees (150–300 ppm). Thus it can be concluded that the present status of Mn in China's rubber trees is higher. Nevertheless, the content of Mn of soil of rubber plantations in China varies significantly according to different soil types, fertilization and management. The difference between the highest and the lowest contents of total Mn could be as high as 140 times and an even greater difference of 200–1240-fold between the highest and the lowest contents of replaceable and reducible Mn has been observed. The storage of reducible Mn is generally insufficient in the soil. Therefore, the symptom of leaf yellowing due to deficiency of Mn has developed in rubber trees in certain parts of rubber tree growing regions in China. The essential oure for leaf yellowing of rubber trees is to raise Mn content in the tree by proper application of fertilizer. The procedures, dosage and timing of the fertilizer for leaf yellowing treatments are suggested.  相似文献   

19.
The leaves of Acer negundo L. var. odessanum (H. Rothe), if permanently exposed to strong sunlight, do not green, but remain yellow and finally become bleached. In yellow leaves the plastids contain single thylakoids and no grana. In plastids of bleached leaves, however, only vesicles are present. The concentration of chlorophylls and photosynthetic activity are much lower in those leaves than in the green ones. If the illumination is reduced (e.g. by shading) both the yellow and the bleached leaves become greenish, and even fully green after a few days at a sufficiently low light intensity. The plastids of yellow-green leaves contain small grana. In dark green leaves the thylakoid system of the chloroplasts is normally developed forming true grana, regardless of whether the leaves were originally green, or became green by shading the yellow or bleached ones. Their pigment concentration and photosynthetic activity are also normal. If green leaves are exposed to sunlight they do not yellow or bleach. During a 3-week period the structure of the thylakoid system did not perceivably change, with the exception that large plastoglobules formed in the stroma.  相似文献   

20.
通过对西藏中、南部16个藏川杨种源地环境特征、植株和枝叶形态特征、生长习性等生物学特性的观测比较,发现藏川杨为高大、长寿乔木,株龄逾千年、株高达45 m、冠幅22 m,分布海拔高度2000~4500 m、分布区域跨越湿润、半湿润、半干旱和干旱区,随着分布区环境变化,不同种源藏川杨的树皮、枝条、芽、叶等形态特征呈现规律性变化,空气湿度增加、树干颜色变深、枝条被毛加重、顶生冬芽变窄、叶片长/宽比增加;半湿润区和灌溉区植株的叶面积、枝条长度增加,湿润区、阴湿地或环境条件恶劣地区植株叶片和枝条生长不佳,枝条干湿比相对较小。结果表明:藏川杨具有很强的环境适应能力和可塑性,耐旱,喜光、抗强光辐射,耐贫瘠、喜中性或弱碱性土壤,具有很高的生态和经济价值。  相似文献   

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