美国红枫变色期苯丙氨酸解氨酶与查儿酮异构酶变化研究

以美国红枫‘秋天火焰’（Acer×freemanif‘Autumn Blaze’）和‘白兰地’（Acer rubrum‘Brandywine’）为试材,研究美国红枫变色过程中,叶片中花青苷含量及其合成相关酶苯丙氨酸解氨酶（PAL）和查儿酮异构酶（CHI））的活性变化。结果表明：两红枫品种叶片中花青苷含量随天数的增加均为单峰曲线,分别在第20d和25d出现峰值;PAL酶活性与花青苷含量成二次曲线关系,CHI酶活性与花青苷含量呈极显著的线性关系;PAI、CHI是秋天火焰花青苷合成的关键酶,CHI是白兰地花青苷合成的关键酶。     

美国红枫变色期二氢黄酮醇还原酶和类黄酮糖基转移酶变化研究

以美国红枫‘秋天火焰’（Acer×freemanii‘Autumn Blaze’）和‘白兰地’（Acer rubrum‘Brandywine’）为试材,研究美国红枫变色过程中,叶片中花青苷含量及其生物合成相关酶二氢黄酮醇还原酶（DFR）和类黄酮糖基转移酶（UFGT）的活性变化。结果表明：两红枫品种叶片中花青苷含量随叶色的变化为单峰曲线,分别在第20d和25d出现峰值;DFR和UFGT酶活性与花青苷含量均成二次曲线关系;UFGT是秋天火焰和白兰地花青苷合成的关键酶,DFR与秋天火焰和白兰地花青苷合成无关。     

红枫叶片花色素及花色苷HPLC定量分析

利用高效液相色谱法定量分析了红枫鲜叶片中Cy3G、Pn3G、Mv、Cy、Pn和Cy3G5G等6种色素。其中Cy3G和色素1是红枫鲜叶片中两种重要色素,其相对含量均超过检测到色素总含量的25%以上,分别占总含量的38.48%和27.3%,鲜叶片中实际含量分别为2.502mg/g和1.775mg/g。除色素1外,较大含量的色素还有色素2(保留时间为18.343min)和色素3(保留时间为17.463min),分别占总含量的6.32%和5.59%,它们可能在红枫叶片呈色过程中起一定作用。未知色素的结构和含量需要进一步鉴定分析。     

红叶桃花青苷和叶绿素年变化规律研究

以红叶桃叶片为材料,在生长期对纯合类型和杂合类型的红叶桃新梢中部叶片中的花青苷和叶绿素进行了研究,结果表明:从5月初到10月上旬,红叶桃纯合类型和杂合类型的花青苷含量在5月中旬达到最高峰后逐渐呈下降的趋势,而叶绿素的含量变化出现多峰现象,纯合类型与杂合类型叶绿素总量变化起伏很大,在7月中旬达到最低谷;纯合类型的花青苷含量均高于杂合类型花青苷含量。     

红檵木叶色变化的生理生化研究

红檵木(Loropetalum chinense var.rubrum)在春季新叶初发时,花红叶红,且叶片红艳可人,具有很高的观赏价值.但随着叶龄的增大,叶色发生较大变化,在初夏叶色变为暗红色,到了盛夏高温季节,叶色几乎变成了绿色,出现了生产上称之的"高温返青"现象.     

金叶榆叶片颜色变化对微观结构的影响

文章研究了金叶榆上部黄叶片、下部绿叶片和白榆叶片的解剖结构和花青苷、叶绿素、类胡萝卜素的含量。金叶榆下部黄叶转为绿叶后,叶片总厚度和上、下表皮厚度、栅栏组织厚度、海绵组织厚度和栅栏组织长宽均有增加;气孔长宽均增大,气孔器密度减小;花青苷含量有所下降,而叶绿素和类胡萝卜素含量明显上升,其中,叶绿素含量增减极为明显。实验表明,金叶榆叶色呈现为金黄色的主要直接原因是叶绿素合成与积累减少。     

桃果实着色期糖组分与果皮花青苷含量的相关性分析

为探究桃果实着色期中糖组分与果皮花青苷之间的相关性,以菁香桃、衡阳水蜜桃、大久保及炎陵黄桃为试材,采用高效液相色谱(HPLC)测定桃果中皮花青苷含量变化、果实可溶性糖的种类及含量变化。结果表明:桃果实成熟时,菁香桃果糖占总糖含量的45.76%,葡萄糖16.58%,蔗糖35.14%,山梨醇3.60%;衡阳水蜜桃果糖占总糖含量的48.45%,葡萄糖23.77%,蔗糖38.82%,山梨醇3.31%;大久保果糖占总糖含量的41.12%,葡萄糖24.11%,蔗糖26.20%,山梨醇3.71%;炎陵黄桃果糖占总糖含量的44.61%,葡萄糖26.58%,蔗糖27.98%,山梨醇3.72%。结果表明:果实成熟时,菁香桃果实中的蔗糖含量最高,为22.338 mg·g^-1,葡萄糖含量为30.419 mg·g^-1,果糖含量在各品种中最高,为54.182 mg·g^-1,山梨醇含量为6.91 mg·g^-1。花后70 d左右,果皮中花青苷含量到达最大值,为7.22μg·g^-1。成熟时,其果皮叶绿素、类胡萝...     

避雨栽培措施对信阳五月鲜桃果实生长的影响

为了探究信阳地区适宜的桃树设施栽培措施,以信阳地区五月鲜桃为试材,以露天栽培为对照,分析不同避雨栽培措施下五月鲜桃果实发育过程中果实纵径和横径以及可溶性糖、可滴定酸、花青苷含量的变化。结果表明,露天栽培措施下果实纵径和横径、可溶性糖含量、花青苷含量基本上在各个时期均最低,避雨条件下采用覆草栽培措施果实纵径和横径最大,可溶性糖和花青苷含量均最高,采收期糖酸比显著高于对照。因此,与露天栽培相比,避雨栽培条件能给信阳五月鲜桃提供更为优良的生长环境,且避雨条件下采用覆草栽培措施果实表现最优。     

美国红枫组织培养技术研究

以种子为外植体,对美国红枫初代培养、增殖培养和生根培养进行了研究,结果表明:美国红枫种子经0.1%升汞消毒8~10 min,0~4℃处理4周后,可有效提高初代培养的无菌率和发芽率;最适诱导培养基为MS+6-BA 0.5 mg·L-1+TDZ 0.1~0.2 mg·L-1+IBA 0.2 mg·L-1,最适扩繁培养基为MS+6-BA 0.2 mg·L-1+TDZ 0.01 mg·L-1+IBA 0.2 mg·L-1,最适生根培养基为1/2MS+ABT 8 mg·L-1,生根率75%,平均根数6~7条。     

榛子苗木几项生理生化指标的研究

研究了榛子苗木生长期间几项生理生化指标的动态变化规律及其对苗木活力的反映 ,结果表明 :叶绿素a、叶绿素b和叶绿素总量呈现出“低—高—低”的变化趋势 ,可溶性糖则相反 ,呈“高—低—高”动态变化 ,SOD和可溶性蛋白质的动态变化基本上是双峰曲线。单因素方差分析表明 ,生长期间叶绿素a和叶绿素总量含量的变化在种和品种之间差异显著 ,其它指标并不显著 ,最后综合各指标将所研究的各品种苗木的活力排序为 :H2 >H3 >H4>欧榛砧木 >平榛。     

Stem girdling manipulates leaf sugar concentrations and anthocyanin expression in sugar maple trees during autumn

To better understand the effects of sugar accumulation on red color development of foliage during autumn, we compared carbohydrate concentration, anthocyanin expression and xylem pressure potential of foliage on girdled versus non-girled (control) branches of 12 mature, open-grown sugar maple (Acer saccharum Marsh.) trees. Half of the study trees were known to exhibit mostly yellow foliar coloration and half historically displayed red coloration. Leaves from both girdled and control branches were harvested at peak color expression (i.e., little or no chlorophyll present). Disruption of phloem export by girdling increased foliar sucrose, glucose and fructose concentrations regardless of historical tree color patterns. Branch girdling also increased foliar anthocyanin expression from 50.4 to 66.7% in historically red trees and from 11.7 to 54.2% in historically yellow trees, the latter representing about a fivefold increase compared with control branches. Correlation analyses indicated a strong and consistent relationship between foliar red coloration and sugar concentrations, particularly glucose and fructose, in both girdled and control branches. Measures of xylem pressure potentials confirmed that girdling was a phloem-specific treatment and had no effect on water transport to distal leaves. Results indicate that stem girdling increased foliar sugar concentrations and enhanced anthocyanin expression during autumn in sugar maple foliage. Native environmental stresses (e.g., low autumn temperatures) that reduce phloem transport may promote similar physiological outcomes.     

Dissolution of polystyrene into p-cymene and related substances in tree leaf oils

We examined the dissolution of polystyrene into p-cymene and related substances to develop an alternative method for the recycling of expanded polystyrene. The dissolving power of p-cymene [212.0 g (100 g solvent)⁻¹] to polystyrene at 50°C compared favorably with those of 2-p-cymenol [156.7 g (100 g solvent)⁻¹], (R)-limonene and its structural isomers [181.7–197.1 g (100 g solvent)⁻¹], and Abies leaf oil [84.7 g (100 g solvent)⁻¹]. The favorable solubility of polystyrene into p-cymene can be explained by the solubility parameter. p-Cymene and polystyrene can be recovered almost quantitatively from the polystyrene solution by simple steam distillation.     

Estimating the maple syrup production potential of American forests: an enhanced estimate that accounts for density and accessibility of tappable maple trees

This paper examines the maple syrup production potential of American forests by analyzing Forest Inventory & Analysis (FIA) data provided by the US Forest Service on the resource of sugar maple (Acer saccharum Marsh.) and red maple (Acer rubrum L.) trees in twenty states. The analysis is based on tree species and size (diameter at breast height, or dbh), ownership category, jurisdiction, the density of maple trees in a stand, and the distance of the stand to an access road. Although there are over 2 billion sugar and red maple trees of tappable size growing in US forests, when narrowed down according to the attributes of an optimal ‘sugarbush’, there are 100 million potential taps from sugar maples alone and 286 million potential taps with sugar and red maples combined. Overall, 45 % of the tappable-size maple trees are found in stands whose density is not high enough to support commercial sap extraction whereas only 6 % are found in stands that are at least 1.6 km from an access road. The ten states with commercial maple syrup industries have a much higher percentage of their maple trees occurring in stands of optimal density and also contain a higher percentage of sugar maple than red maple trees. States that are utilizing the highest percentage of their potential sugarbushes include Vermont and Maine, whereas states that have significant room for expansion include Michigan, New York, and Pennsylvania.     

Sweet trees, sour circumstances: the long search for sustainability in the North American maple products industry

Maple sugar and maple syrup have long been important non-timber forest products in North America. We examined the historical and the scientific literature to determine the long-term sustainability of the industry in an economic, an ecological, and a cultural context. During the 18th and 19th centuries, maple sugar was an inexpensive substitute for cane sugar and a cash crop that fit into the work schedule of the northern farmer. Maple syrup replaced maple sugar as the mainstay of the industry at the end of the 19th century as increasingly cheaper cane sugar and other sweeteners undercut the sugar market. Active government intervention and support have made Quebec the major bulk supplier of maple syrup today. Quebec alone produces approximately 80% of the world’s supply of maple products. A series of good sap years and production in excess of demand, however, has recently reduced the price of bulk syrup and the profit of producers in Quebec. Producers in the United States have focused on the more lucrative and price stable retail syrup market.

Farming practices in the late 18th and early 19th centuries tended to clear away sugar maple on the more fertile, level sites and preserve sugar maple as a source of fuel wood, sugar and syrup on the less accessible, marginal sites. The crude tapping procedures employed at the same time often killed the trees. Widespread grazing in the 20th century and more recently diameter-limit cutting of even-aged stands have hindered the regeneration of the sugarbush. An emphasis on monocultures and global warming currently threatens the sustainability of the sugarbush. On the whole, however, the maple products industry has probably increased sugar maple’s representation in the forest. From a cultural standpoint, the industry represents a positive work experience that unites families, connects one to the land, and provides a sense of continuity with the past.     

中国中部城市发展乡土彩叶树种的研究

中国中部城市大多人口稠密,景观单调,生态环境条件欠佳,缺乏绿化和色彩,同时外来彩叶植物在园林配置上的盲目引种可能引发潜在的生态安全危险。从建设生态园林的观点出发,在今后的园林配置中,特别是在以城市生态圈为中心的林业建设中应重视乡土彩叶树种的发展。本文在宫胁造林法理论的基础上提出了20种核心乡土彩叶树种与51种重要彩叶树种,并对它们的习性、彩叶观赏品质及其配置要点进行了论述和评价。     

紫花槭秋季叶片呈色生理变化研究

为了探寻影响紫花槭叶色变化的主要因素,从而为其园林配置提供理论依据,对紫花槭秋季叶片转色不同时期的叶色参数、色素含量、相关酶活性、碳水化合物和矿质元素含量进行了测定。结果表明:1)紫花槭叶色参数L值先上升后降低,a值呈持续上升趋势,b值呈先上升后下降再上升的趋势;2)紫花槭叶片叶绿素含量呈下降趋势,类胡萝卜素含量呈先下降后上升再下降的趋势,花色素苷含量呈上升趋势;3)苯丙氨酸解氨酶(PAL)、查尔酮异构酶(CHI)、查尔酮还原酶(CHR)活性均呈先升高后降低的趋势;4)碳水化合物中蔗糖含量呈先下降后上升再下降的趋势;5)矿质元素中氮、钾含量的变化趋势相同,均呈下降趋势,磷含量呈先上升后下降的双峰趋势,镁含量呈先上升后下降的趋势,钙含量呈先下降后上升再下降的趋势。对不同色素与其他生理指标的相关性分析结果表明:叶绿素含量与氮、钾均存在极显著的正相关关系,与钙存在显著的正相关关系;类胡萝卜素含量与其他指标的相关性均未达到显著水平;花色素苷的含量与PAL、CHI酶活性和氮、钾含量间均呈极显著负相关,与CHR酶活性及钙、镁含量间均呈显著负相关,而与淀粉、蔗糖含量间均存在正相关,但不显著;色素与磷含量无明显的相关性。     

南京的竹叶锈病及其病原菌

在南京发现竹叶锈病菌有2介种,即刚竹柄锈菌(Puccinia Phyllostachydis)和长角柄锈菌(P.logicornis),它们可以侵染多种竹,但寄主不完全相同。它们的夏孢子都可以越冬。冬孢子堆始于2月底生于叶背,冬孢子间结合较紧,呈深锈褐色半球状突起。夏孢子必须在饱和湿度或水滴中才能萌发,最适温为20℃。发病高峰分别为4月和9～10月间。病菌夏孢子堆常被真菌Myceliophthora sp.(Ophionectria uredinicola)寄生,寄生率高达63.4％～94.3％。     

光胁迫对中华金叶榆叶色的影响

为明确光照对中华金叶榆叶色发育的影响,以2a生的中华金叶榆作为试材,进行不同梯度的光照胁迫。研究结果表明：随着光照强度的降低,中华金叶榆叶片叶绿素a、叶绿素b、叶绿素总量和类胡萝卜素的含量都不断增加,而类胡萝卜素与叶绿素含量的比值、花色素苷与叶绿素总量的比值则不断的下降;叶片花色素苷含量不断增加;叶片pH值小于7,pH值不断增大,逐渐偏向中性;光照强度的降低抑制PAL的活性;可溶性糖含量随光照强度的降低不断增加,与花色素苷含量呈正相关。     

Interpreting the decrease in leaf photosynthesis during flowering in mango

Little is known about the effect of flowering on leaf photosynthesis. To understand why net photosynthesis (A(net)) is lower in Mangifera indica L. leaves close to inflorescences than in leaves on vegetative shoots, we measured nitrogen and carbohydrate concentrations, chlorophyll a fluorescence and gas exchange in recently matured leaves on vegetative terminals and on floral terminals of 4-year-old trees. We used models to estimate photosynthetic electron fluxes and mesophyll conductance (g(m)). Lower A(net) in leaves close to developing inflorescences was attributable to substantial decreases in stomatal conductance and g(m), and also in photosynthetic capacity as indicated by the decrease in the light-saturated rate of photosynthetic electron transport (J(max)). The decrease in J(max) was the result of decreases in the amount of foliar nitrogen per unit leaf area, and may have been triggered by a decrease in sink activity as indicated by the increase in the hexose:sucrose ratio. Parameters measured on leaves close to panicles bearing set fruits were generally intermediate between those measured on leaves on vegetative shoots and on leaves close to inflorescences, suggesting that the changes in A(net) associated with flowering are reversible.     

Shoot biomass growth is related to the vertical leaf nitrogen gradient in Salix canopies

Plant canopy optimization models predict that leaf nitrogen (N) distribution in the canopy will parallel the vertical light gradient, and numerous studies with many species have confirmed this prediction. Further, it is predicted that for a given canopy leaf area, a low vertical light extinction coefficient will promote rapid growth. Therefore, the ideal canopy of fast-growing plants should combine high leaf area index with a low light extinction coefficient; the latter being reflected in a flat vertical leaf N gradient throughout the canopy. Based on data from an experimental Salix stand (six varieties) grown on agricultural land in central Sweden, we tested the hypothesis that shoot growth is correlated with vertical leaf N gradient in canopies of hybrid willows bred for biomass production, which could have implications for Salix breeding. Tree improvement research requires screening of growth-related traits in large numbers of plants, but assessment of canopy leaf N gradients by chemical analysis is expensive, time-consuming and destructive. An alternative to analytical methods is to estimate leaf N gradients nondestructively with an optical chlorophyll meter (SPAD method). Here we provide a specific calibration for interpreting SPAD data measured in hybrid willows grown in biomass plantations on fertile agricultural land. Based on SPAD measurements, a significant and inverse relationship (r(2) = 0.88) was found between shoot biomass growth and vertical leaf N gradient across canopies of six Salix varieties.