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《Forest Ecology and Management》1997,97(1):85-90
A light measuring system is introduced to characterize spatial and temporal variation of photosynthetic photon flux density on small scales within plant canopies. This system consists of an array of 100 gallium arsenide phosphide (GaAsP 1118), a high-speed data-logger with a maximum of 360 channels, and a portable computer. GaAsP cells, being small in size (total surface area of a single cell 5 × 6 mm), light in weight and inexpensive, make it possible to sample photon flux density simultaneously for a large number of microsites. With the high-speed data logger, the system provides a useful tool for measuring dynamics of sunflecks within plant canopies. It is easy to separate spatial and temporal components of the variation in photon flux density from the measurement using the system. A testing measurement was carried out in a tropical forest. Considerable spatial and temporal variations of photon flux density along a 50 cm transect were observed in a gap of the forest. Some potential applications of the system were also discussed. 相似文献
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光皮树果实的数量性状变异 总被引：2，自引：0，他引：2
对来自江西赣州和广东乐昌的21株光皮树优树果实的果肉厚度、鲜果千粒质量、种子千粒质量、果肉含油量、种子含油量、鲜果大小和种子大小等7项数量性状指标进行了研究.结果表明:果实数量性状的变异系数范围为4.35%～23.08%,其中种子大小、鲜果大小、种子含油量、果肉含油量、种子千粒质量、鲜果千粒质量和果肉厚度的变异系数分别为4.35%、6.78%、14.28%、14.39%、17.89%、19.06%和23.08%.果肉厚度与种子千粒质量、鲜果大小与种子大小均呈极显著正相关;种子大小与鲜果千粒质量、鲜果大小和鲜果千粒质量均呈显著正相关.21株光皮树优树果肉中含油量的变异幅度为26.35%～56.88%,种子中含油量的变异幅度为11.77%～19.83%. 相似文献
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《林业研究》2021,32(2)
To analyze the degree and pattern of phenotypic variation in leaves of Tetracentron sinense Oliv from the perspective of genetic and environmental adaptation and thus contribute to effective evidence-based conservation and management strategies for germplasm resources,we measured 17 morphological and epidermal micromorphological leaf traits from 24 natural populations of T.sinense.Nested analysis of variance,multiple comparison,principal component analysis(PCA),cluster analysis,and correlation analysis were used to explore phenotypic leaf variation among and within populations and potential correlations with geographic and environmental factors.There were significant differences in 17 leaf phenotypic traits among and within populations.The mean phenotypic differentiation coefficient of the 17 traits was 56.34%,and the variation among populations(36.4%) was greater than that within populations(27.2%).The coefficient of variation(CV)of each trait ranged from 4.6 to 23.8%,and the mean was11.8%.Phenotypic variation of leaves was related to environmental factors such as average annual sunshine hours,average July temperature,and average annual rainfall.The variation changed along gradients of longitude,latitude,and altitude.The PCA clustered the 24 natural populations into four groups.Our study suggests that phenotypic variation in T.sinense occurred primarily among populations,with moderate levels of phenotypic differentiation among populations and low levels of phenotypic variation within populations.The plant's poor adaptability to the environment is likely an important contributor to its endangerment.Accordingly,conservation strategies are proposed to protect and manage the natural populations of T.sinense. 相似文献
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At the intra-plant level, temporal and spatial variations in plant defense traits can be influenced by resource requirements, defensive priorities and storage opportunities. Across a leaf age gradient, cyanogenic glycoside concentrations in the rainforest understory tree Ryparosa kurrangii B.L. Webber were higher in young expanding leaves than in mature leaves (2.58 and 1.38 mg g(-1), respectively). Moreover, cyanogens, as an effective chemical defense against generalist herbivores, contributed to a defense continuum protecting foliar tissue during leaf development. Chemical (cyanogens and phenolic compounds) and phenological (delayed greening) defense traits protected young leaves, whereas mature leaves were largely protected by physical defense mechanisms (lamina toughness; explained primarily by leaf mass per area). Cyanogen concentration was considerably higher in floral tissue than in foliar tissue and decreased in floral tissue during development. Across contrasting tropical seasons, foliar cyanogenic concentration varied significantly, being highest in the late wet season and lowest during the pre-wet season, the latter coinciding with fruiting and leaf flushing. Cyanogens in R. kurrangii appear to be differentially allocated in a way that maximizes plant fitness but may also act as a store of reduced nitrogen that is remobilized during flowering and leaf flushing. 相似文献
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《Southern Forests》2013,75(2):69-74
African sandalwood (Osyris lanceolata) is widely harvested in East Africa for extraction of oil, which is used in the fragrance and perfumery industry. Over the years, harvesting of the species has been concentrated to female plants because it is claimed that they yield more and better quality oil compared to males. However, data to support these claims is lacking. Osyris lanceolata is also used extensively by pastoralists as feed supplement during the dry season, yet little information on the species’ nutritive value exists. Oil yield and quality variations between male and female O. lanceolata and its nutritive values were evaluated to ascertain the purported reasons for sex selectivity in harvesting, and to determine the potential value of the species as a fodder plant. Oil yield was determined by extracting oil from a known amount of wood, while quality assessment was done by determining the amount of santalol, a prime determinant of sandalwood oil quality. The species’ potential as a fodder plant was determined by analyzing the nutritive value and digestibility of leaves and fruits. There was no significant variation (p = 0.856) in oil yield between sexes, though populations differed significantly (P < 0.001). The highest oil yield was 9.32 ± 0.611%. Likewise, sexes did not differ significantly (P = 0.655) in oil quality, though populations differed significantly (P < 0.001). The highest santalol content was 11.1%. It is concluded that sex selectivity during harvesting has no relation to oil yield and quality. However, population selectivity is strongly justified due to the huge variation in oil yield and quality, and is likely to be the major reason for over-exploiting some populations. It is recommended that there is a need to refrain from overharvesting of females within populations, since the practice is likely to erode the genetic vigour of the species and affect its sustainability. Nutritive studies revealed the species to have 15.9–19.7% crude protein, 15.9–24.0% crude fibre, 0.77–0.81% fat/oil, 97.5–97.8% dry matter, 8.5–10.3% ash content, 72.2–72.4% digestibility. These figures are within the acceptable range, suggesting that both leaves and fruits of the species are a potential alternative source of animal protein where protein supplements are not available or expensive. 相似文献
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本研究以研究组初步筛选的4个编号I-IV的棱角山矾叶型变异类型为研究对象,开展其叶型变异分析及基于ISSR分子标记的变异类型分子甄别。叶型变异分析表明,4个类型的叶长、叶宽尺度均呈现Ⅰ型<Ⅱ型<Ⅲ型<Ⅳ型趋势。Ⅰ型与Ⅱ型的叶型指数数值相近,这与两者具有相似的叶片形状一致。Ⅰ型叶型指数变异系数最小（7.57）,同时叶长与叶宽显著相关（r=0.908,p<0.01）,说明该类型叶片生长过程中长与宽的扩展速度相对一致。变异类型的ISSR分子甄别显示4个类型的基因多样度为0.2562。利用UBC843、UBC848及UBC8453个分子标记可一次性鉴别4个类型。亲缘关系分析显示,Ⅰ型与其他3个类型的亲缘关系最远,Ⅲ型与Ⅳ型亲缘关系最近;采用UPGMA法按遗传距离进行聚类,属于小叶型的棱角山矾Ⅰ型与Ⅱ型聚成一类,与大叶型的Ⅲ型与Ⅳ型成组分离,这与4个类型的表型表现一致。综合表型与分子数据,Ⅰ型可进一步作为棱角山矾小叶型品种进行培育。 相似文献
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根据南方的气候特点，对不同地区的不同环境和植物种类组织，在全省１４个市（州）开展了新剂型的应用研究。试验结果表明：绿色植物生长调节剂比原ＡＢＴ生根粉１～５号使用简便，效果更好。可大力应用。 相似文献
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Exposure to standard solution S extract ofPunica granatum, Thymus vulgaris andArtemisia absinthium for 72 h reduced the numbers of active nematodes by 100% forMeloidogyne incognita and by 95.7%, 71.4% and 42.9% forHelicotylenchus dihystera, respectively. Exposure to S/2 dilutions for 72 h reduced nematode motility by 100%, 77.3 and 72.7% forM. incognita, and by 92.9%, 37,1%, and 37,1% forH. dihystera, respectively. As exposure to S and S/2 extracts ofCitrullus colosynthis andRicinus communis reduced nematode motility by less than 32% forM. incognita and by less than 30% forH. dihystera. WhenM. incognita andH. dihystera were transfered to water for 72h, more than 85% of the individuals resumed normal movement at all extract dilutions except S ofA. absinthium andT. vulgaris and S and S/2 ofP. granatum. However, recovery ofM. incognita was more less than that ofH. dihystera. Exposure to S extracts ofP. granatum andT. vulgaris for 30 days reduced egg-hatching ofM. incognita by 100% and by 98.7% for S/2 dilutions. Also, 98.7% reduction in the egg-hatching was obtained by S ofA. absinthium. Extracts ofC. colosynthsis andR. communis gave less egg-hatching inhibition. Acetylcholinesterase (AChE) activity was suppressed by more than 75% inH. dihystera treated with S of each ofP. granatum, T. vulgaris andA. absinthium. However, the former extract gave the highest AChE inhibition (98.7%). When nematodes were treated with oxamyl (Vydate 24%), AChE activity was suppressed by 53.3%. The other extract dilutions suppressed AChE activity by less than 50%. 相似文献
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对落羽杉属不同种源、家系和树种苗期、幼林期生长量（高、胸径、冠幅）、保存率和生物量及其分配（总生物量，干、枝、叶、根生物量及其比值）进行了５年研究。发现落羽杉不同种源、家系间、内均存在显著的性状变异。变异系数以种源、家系间最大，个体间其次。生物量的变异系数大于生长量。未发现不同种源、家系在不同地点存在明显互作。采用多性状综合选择法评选出７个优良种源、家系或树种（１６００、４０１、中山杉、３０４、５０２、鸡公山落羽杉和７０１），它们的生长量、生物量大，叶生物量较大，地上部分生物量／根生物量比值大。其综合选择指数值比平均值大１３．９７％～３５．３３％，树高比平均值大１１．２２％～２４．４９％，比本地近似树种（江宁池杉）大３４．５４％～４６．１８％；胸径比平均值大１２．８１％～４８．２８％，比江宁池杉大３８．７９％～８２．４２％；总生物量比平均值大５４．５９％～１１０．６７％；保存率一般也高于平均值及本省江宁池杉。这些优良种源、家系或树种可以在江苏全省及国内类似地区作用材、防护和观赏树种推广应用。 相似文献
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Yang Chuanping Liu Guifeng Xu Jiachun Cai Baoming Xia Dean Yang Shuwen Zhang Peigao 《林业研究》1997,8(1):3-9
On the basis of the data of provenance test for 10 years in the total natural range ofLarix olgensis from 10 seeds collection sites, the geographic variation patterns have been made by means of canonical correlation analysis:
(1) The basic variation patterns of growth characters is in vertical gradual change along the elevation gradient as principal,
and gradual change along the latitude as supplement. (2) The Xiaobehu provenance with low elevation and low equivalent latitude
is the good gene resource center ofL. olgensis. It has the genetic characters of rapid growth, high stability and fine timber quality. (3) The synthetical interaction between
water and heat factors is the major factor to produce the variation ofL. olgensis and the temperature is the principal one. (4) Among the genetic variations of geographic population characters, the variation
of growth is the most obvious one, and it could be taken as the main character for provenance division. (5) By allocating
the seeds from the low equivalent latitude region to the northern suitable afforestation areas, the greater genetic gain could
be obtained.
(Responsible Editor: Chai Ruihai) 相似文献
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植物促生根圈细菌诱导植物系统抗性的研究进展 总被引：2，自引：0，他引：2
该文简要回顾了植物根圈促生细菌(PGPR)能够诱导植物系统抗病性(ISR)这一领域的研究历史,对ISR作用机理、研究法则、研究内容及其它相关问题进行了总结探讨,并展望其未来的研究方向。 相似文献