不同防寒措施对引种的加拿大糖槭抗寒生理指标的影响

对引种的2年生加拿大糖槭苗分别进行稻草防护、窖藏处理,并以野外露地越冬生长的苗木为对照,研究不同处理的加拿大糖槭苗在生理及形态等方面对低温的反应,结果表明:在自然条件下的苗木形态指标不如稻草防护的苗木,窖藏的加拿大糖槭的苗木质量又优于稻草防护的加拿大糖槭,因此,对引种幼苗,最好保护方法是窖藏法。     

加拿大糖槭

乔木,高可达24m,冠幅16m,树型雄伟,木质坚硬,首选遮荫树种,秋季叶片金黄色至桔红色。适应范围广,喜排水良好、潮湿的酸性土壤,耐寒(零下40℃),适应三北和南方各省区气候种植。(摘自:中国林业网)加拿大糖槭     

糖槭的引种试验研究

在大兴安岭西部地区对糖槭生长特性、抗病性及抗逆性进行试验研究,证明该树种在大兴安岭岭西地区生长良好。     

加拿大魁北克枯萎糖槭林的施肥研究

1 引言80年代初期,魁北克地区出现的流行性糖槭枯萎现象就引起了人们的注意。1985年,魁北克南部许多地区也陆续发现糖槭枯萎病。Benier(1988)等人的研究表明,糖槭枯萎与缺素有关,其分布随地区和土壤类型而变化。许多环境因子对森林生长也造成威胁,酸雨是其中之一。加拿大酸雨(pH≈4.2)最严重的地区恰是枯萎糖槭林的分布区。1981～1982年,霜冻导致许多糖槭林根部损伤。70及     

银糖槭引种适生性的初步研究

银糖槭树引种至川中丘陵及北缘山地,在海拔900m以下地区,前期生长较均正常,年均高生长量可达125.3cm,地径生长量可达2cm.但光肩星天牛危害较剧,可导致成片林分死亡.近期内不宜大面积引种推广银糖槭.     

糖槭含糖量的调查研究

通过糖槭树含糖量的调查，进而对影响糖液采收量的因子进行了研究。其结果表明，糖械树液的含量量在２－８．６％之间，胸径２０ｃｍ的糖械树在树干南面采取钻孔采液法，可采取糖液１３００ｍｌ，即产固体糖０．８７ｋｇ。采割糖液时间应在３月初至４月上旬。采割方法及割方向对糖液采收量有一定的影响。在糖液采收期内，采收时间与糖液含量量关系密切。     

糖槭叶枯病的初步研究

人工诱发试验表明，糖槭叶枯病的病原菌为Ｃｈｅｎ叶槭叶点霉。该菌在ＰＤＡ等四种培养基上均能很好生长。菌丝生长温度范围伙１５℃￣３０℃，以２５℃生长最好。     

糖槭叶枯病的初步研究

人工诱发试验表明,糖槭叶枯病的病原菌为木岑叶槭叶点霉ｐｈｙｌｏｓｔｉｃｔａｎｅｇｕｎ－ｄｉｎｉｓＳａｃｃ．ｅｔＳｐｅｇ．。该菌在ＰＤＡ等四种培养基上均能很好生长。菌丝生长温度范围为１５℃～３０℃,以２５℃生长最好。在ｐＨ６时菌丝生长最好。该病菌通过气孔侵入,潜育期为１０～１８天。病菌以分生孢子无菌丝在病叶上越冬,成为翌年初侵染源。喷洒７０％甲基托布津１０００倍液和７５％百菌清８００倍液均收到较好防治效果。     

糖槭含糖量的调查研究

通过糖械树含糖量的调查，进而对影响糖液采收量的因子进行了研究。其结果表明，糖械树液的含糖量在２％～８．６％之间。胸径２０ｃｍ的糖械树在树干南面采取钻孔采液法，可采取糖液１３００ｍｌ，即产固体糖０．８７ｋｇ。采割糖液时间应在３月初至４月上旬。采割方法及采割方向对糖液采收量有一定的影响。在糖液采收期内，采收时间与糖液含糖量关系密切。     

复方中药糖槭合剂呼吸系统药理研究

复方中药糖槭合剂呼吸系统研究,国内外首报,实验证明该合剂具有中等程度的镇咳、祛痰和平喘作用。大白鼠LD50为383ml/kg,体重PO(寇氏法):白鼠LD50为324ml/kg,体重PO(目测概率单位法)     

Leaf-level acclimation to gap creation in mature Acer saccharum trees

Leaf-level morphological and physiological responses of mature, winter-deciduous, shade-tolerant Acer saccharum Marsh. trees to gap formation caused by selection harvest were studied experimentally over a 2-year period. We found no evidence for either physiological stress or positive acclimation following gap creation during the 1-2-week post-harvest period. Rather, lower-canopy leaves showed gradual increases in area-based maximum photosynthetic rates (Amax-area), stomatal conductance (gs), and leaf nitrogen concentration (Narea) over the entire 2-year study. These acclimation responses were directly related to changes in leaf mass per unit area (LMA) in the subsequent two leaf flushes. No change in Amax-area, gs, Narea, or photosynthetic nitrogen-use efficiency was observed that could not be accounted for by changes in LMA. The gradual acclimation responses in the lower canopy may account, in whole or in part, for the approximately 2-year lag in post-harvest growth response observed in Acer saccharum.     

Chlorophyll content monitoring in sugar maple (Acer saccharum)

We conducted two experiments to determine the usefulness of a chlorophyll content meter (CCM) for the measurement of foliar chlorophyll concentration in sugar maple (Acer saccharum Marsh.) in the fall color period. In Experiment 1, four sugar maple trees were visually assigned to each of four fall foliage color categories in October 1998. On four dates in the fall of 1999, leaves were taken from the trees and analyzed for chlorophyll concentration by absorbance of pigment extracts and by determination of the chlorophyll content index (CCI) with a CCM. The two measures of chlorophyll concentration were strongly correlated (P < 0.001, r2 = 0.72). In Experiment 2, the CCI of leaves from sugar maple trees subjected to one of four fertilization treatments (lime, lime + manure, lime + 10:10:10 N,P,K fertilizer and an untreated control) were determined with a CCM. Treatment effects were distinguishable between all pairwise comparisons (P < 0.001), except for the lime versus lime + NPK fertilizer treatments.     

Ecophysiological attributes of the native Acer saccharum and the exotic Acer platanoides in urban oak forests in Pennsylvania, USA

When the exotic Acer platanoides L. (Norway maple) and the native A. saccharum Marsh. (sugar maple) grow together in the understories of urban Quercus forests in the eastern USA, average annual height growth increments are nearly twice as large in A. platanoides as in A. saccharum, 19.26 +/- 3.22 versus 10.01 +/- 1.69 cm. We examined several ecophysiological mechanisms that might be associated with the superior invasive ability and growth of A. platanoides in two urban oak forests in Pennsylvania. Leaf longevity was 12 days greater in A. platanoides than in A. saccharum. In addition, leaf mass/leaf area ratio was greater in A. platanoides than in A. saccharum (2.67 +/- 0.03 versus 2.32 +/- 0.02 mg cm(-2)); however, leaf thickness was significantly lower in A. platanoides than in A. saccharum suggesting that A. platanoides contains more dense palisade and mesophyll cell layers than A. saccharum. Field net photosynthesis (mass basis) and photosynthetic light response curves (area basis) indicated significantly greater carbon assimilation, and nitrogen and phosphorus use efficiencies in A. platanoides than in A. saccharum. Acer platanoides also exhibited higher water use efficiency than A. saccharum (0.88 +/- 0.12 versus 0.32 +/- 0.09 mmol CO(2) mol(-1) H(2)O). Acer platanoides exhibited significantly lower osmotic potentials than A. saccharum, but a similar relative water content at zero turgor. We conclude that A. platanoides utilizes light, water and nutrients more efficiently than A. saccharum.     

Hydraulic resistance in Acer saccharum shoots and its influence on leaf water potential and transpiration

A new method is presented for measuring whole-shoot hydraulic conductance, K(T) (kg s(-1) MPa(-1)). The method was also used to determine other conductance values in maple (Acer saccharum Marsh.) stem segments of differing diameter including: K(h) (absolute conductance or conductance per unit pressure gradient, kg s(-1) m MPa(-1)), K(s) (specific conductance or K(h) per unit wood area, kg s(-1) m(-1) MPa(-1)), and LSC (leaf specific conductance or K(h) per unit leaf area, kg s(-1) m(-1) MPa(-1)). A regression of K(T) versus stem basal diameter, D (m), gave K(T) = 5.998 x 10(-2) D(1.402) (R(2) = 0.986 for D from 0.001 to 0.1 m) and a regression for leaf area, A(L) (m(2)), gave A(L) = 4.667 x 10(3) D(2.007) (R(2) = 0.981 for D from 0.001 to 0.3 m). More than 50% of the resistance to water flow in large shoots (0.1 m in diameter and 8 to 10 m long) was contained in branches less than 0.012 m in diameter, i.e., in the distal 1.5 m of branches. We used the regressions to predict the steady state difference in pressure potential, P, between the base of a shoot of diameter D and the average pressure potential at the apices of the shoot; the relation is given by P = 7.781 x 10(4) E D(0.605), where E is the average evaporative flux density (kg s(-1) m(-2)) in the leaves attached to the shoot. After comparing the predictions of this equation to field observations of E and leaf water potential and stomatal conductance, we concluded that the hydraulic conductance of large maple shoots is sufficiently low to prevent maximum stomatal conductance in maple leaves.     

Crown architecture of stand-grown sugar maple (Acer saccharum Marsh.) in the Adirondack Mountains

Leaf and crown morphology of shade-tolerant sugar maple (Acer saccharum Marsh.) were examined to test the hypotheses (1) that leaf area exhibits significant plasticity both within and between crown classes and individual tree crowns and (2) that leaf area is accurately predicted from estimates of crown volume. A total of 18 trees, ranging from 3.3 to 43.4 cm dbh, were felled and dissected into upper, middle, lower, and below-crown layers, for measurements of leaf, bark, and xylem dimensions. For dominant trees only, bark thickness and xylem radii were higher within the crown than below the crown. Cumulative leaf area index increased with decreasing stratum height at similar rates in all trees, except for two trees that were located in the understory. Area leaf weight declined with decreasing stratum height within the crown of all except four overstory trees. These four trees showed an increase with decreasing stratum height, i.e., leaves were heavier per unit area in the lower crown stratum and below the crown than they were at mid-crown. Within-tree leaf area density was usually higher in the upper crown of overstory trees and in the lower crown of understory trees. Total crown volume was the best predictor of whole-tree leaf area, but it was only slightly better than dbh.     

北美引进泡泡树的研究进展

泡泡树是一种原产于北美洲的乔木果树,其果实味美,营养丰富,富含多种矿质元素、维生素和氨基酸,具有较高的开发利用价值.目前,国内的一些科研单位已对泡泡树进行了引种栽培试验,并获得了成功.同时,对泡泡树的营养成分、繁殖技术、种植技术、遗传多样性等方面进行了研究,并取得一定进展.本文将对泡泡树研究现状进行整理,分析当前泡泡树...     

云南引种的元宝枫果实性状变异研究

以云南引种的46株元宝枫的果实为研究材料,对其果实的9个性状变异和各性状间的相关性进行了分析研究。结果表明,(1)果实性状的株间变异较株内变异显著;(2)果实各性状变异系数由大到小依次为空壳比率、果实厚度、种子千粒重、果实千粒重、着生痕长度、种子厚度、果实宽度、带翅果实长度、果实长度;(3)果实千粒重与种子千粒重呈高度正相关,与果实宽度、种子厚度、果实厚度呈显著正相关,与带翅果实长度、着生痕长度及果实长度呈低度正相关。种子千粒重除了与果实千粒重呈高度正相关外,还和带翅果实长度、种子厚度、果实厚度呈显著正相关,而且和果实宽度呈低度正相关。以此评选出引种地果实性状优良、产量高的元宝枫单株。     

Water relations and gas exchange of Acer saccharum seedlings in contrasting natural light and water regimes

Field measurements were made of leaf photosynthesis (A), stomatal conductance (g) and leaf water relations for sugar maple (Acer saccharum Marsh.) seedlings growing in a forest understory, small gap or large clearing habitat in southwestern Wisconsin, USA. Predawn water status, leaf gas exchange and plasticity in field and laboratory water relations characteristics were compared among contrasting light environments in a wet year (1987) and a dry year (1988) to evaluate possible interactions between light and water availability in these habitats. Leaf water potentials (Psi(leaf)) at predawn and midday were lower for clearing than gap or understory seedlings. Acclimation of tissue osmotic potentials to light environment was observed among habitats but did not occur within any of the habitats in response to prolonged drought. During a summer drought in 1988, decreases in daily maximum g (g(max)) and maximum A (A(max)) in clearing seedlings were correlated with predawn Psi(leaf), which reached a seasonal minimum of -2.0 MPa. Under well-watered conditions, diurnal fluctuations in Psi(leaf) of up to 2.0 MPa in clearing seedlings occurred along with large midday depressions of A and g. In a wet year, strong stomatal responses to leaf-to-air vapor pressure difference (VPD) in sunny habitats were observed over nine diurnal courses of gas exchange measurements on seedlings in a gap and a clearing. Increasing stomatal limitations to photosynthesis appeared to be responsible for the reduction in A at high VPD for clearing seedlings. In understory seedlings, however, low water-use efficiency and development of leaf water deficits in sunflecks was related to reduced stomatal limitations to photosynthesis relative to seedlings in sunny habitats. Predawn Psi(leaf) and VPD appear to be important factors limiting carbon assimilation in sugar maple seedlings in light-saturating irradiances, primarily through stomatal closure. The overall results are consistent with the idea that sugar maple seedlings exhibit "conservative" water use patterns and have low drought tolerance. Leaf water relations and patterns of water use should be considered in studies of acclimation and species photosynthetic performance in contrasting light environments.     

Sticker stain formation in hardwoods: Isolation of scopoletin from sugar maple (Acer saccharum Marsh.)

Summary The extractives of clear and sticker stained sapwood from sugar maple (Acer saccharum Marsh.) were isolated and screened for low molecular-weight phenols, which could be involved in the formation of sticker stain. Scopoletin (7-hydroxy-6-methoxycoumarin) was identified as the major low molecular-weight free phenol in the samples studied. This compound, which has not previously been reported in extractives from maple wood, was quantified in stained and clear samples. Additionally, the two major fatty acids present were identified as palmitic acid and linolenic acid, and the two major sterols as stigmasterol and sitosterol.The authors are indebted to Mr. Peter Garrahan for provision of wood samples and the Canadian Forestry Service for financial support