Differentiation among effects of nitrogen fertilization treatments on conifer seedlings by foliar reflectance: a comparison of methods

Analysis of reflectance can be used to estimate foliar concentrations of photosynthetic pigments, thus providing information on the physiological status of green plants. We compared several methods of reflectance analysis for the capacity to differentiate among effects of fertilization treatments across different irradiances on seedlings of Engelmann spruce (Picea engelmanii Parry ex Engelm.). Seedlings were grown in two light treatments (0 and 60% shade) and three nitrogen (N) treatments (10, 25 and 100 mg N l-1) for one growing season, after which foliar reflectance of the needles was measured. Five indices were tested: R550 (% reflectance at 550 nm); red edge position; the ratio R698:R760; the structure independent pigment index (SIPI); and the photochemical reflectance index (PRI). Both the light and nutrient treatments significantly affected foliar chlorophyll a and b and carotenoid concentrations. Among the indices tested, R550, red edge position and R698:R760 ratio were related to chlorophyll concentration, and were significantly affected by both light and N treatments. Both SIPI and PRI were related to chlorophyll and carotenoid concentrations. Among these relationships, PRI was affected by both treatments, whereas SIPI was sensitive to N treatment but not to light treatment. All five indices were weakly but significantly correlated with growth as measured by dry weight.     

自然背景下基于反射模型的树叶彩色图像分割

为实现固碳释氧测量中叶片图像的高精度分割,提出一种基于反射模型的树叶彩色图像分割算法.首先,在RGB颜色空间中,针对光照对于叶片颜色不一致的影响,采用改进的白平衡方法进行滤波;其次,针对RGB颜色空间的非均匀性、色域窄、亮度分量混合的问题,将其变换到Lab颜色空间,去除亮度分量,消除光照对于叶片分割的影响;然后,依据Lab颜色空间的均匀性,定义颜色特征的欧氏距离为聚类准则;最后采用最小分类器进行聚类分割.实验结果的对比分析表明该方法是有效的.     

基于反射光谱的山核桃幼苗氮素营养状况分析

山核桃(Carya cathayensis)是世界著名的干果之一,也是重要的木本油料作物,其油味清香、营养丰富,是优良的休闲保健食品.山核桃长期以来产量不稳、大小年现象明显,通过肥水管理、病虫害防治等有效管理措施,大部分产区大小年现象都明显趋缓,产量逐年上升(黎章矩,2003).我国山核桃研究起步较晚,在其营养方面的研究甚少.     

板栗苗期生长发育规律研究

采用实验室检测和野外调查相结合方式,对板栗1年生嫁接苗生长发育动态、生理指标以及光能利用效率等内容进行研究,研究结论表明:板栗1年生嫁接苗地径和树高生长趋势均呈单"S"曲线变化,其中邵阳城步和常德石门板栗品种幼苗生长量,叶片蛋白质含量和叶绿素含量表现突出;邵阳城步板栗品种地径递增量为1.57cm,树高递增量为144.87cm,叶片蛋白质含量保持在6.42%,叶绿素含量为17.68g·L^-1;常德石门板栗品种地径递增量为1.46cm,树高递增量为142.07cm,叶片蛋白质含量维持在4.64%,叶绿素含量为21.92g·L^-1,说明邵阳城步和常德石门板栗品种幼苗生命活动较为旺盛。依据硝酸还原酶活性大小变化,岳阳临湘晚熟,岳阳临湘早熟和常德石门品种抗逆性较强,而邵阳城步品种抗逆性相对较弱。     

RGB图像分析法测定台风0613诱发的竹叶黄化和坏死(英文)

遭遇台风0613号袭击之后,日本山口市的许多乔木和灌木出现叶尖和叶缘甚至整叶黄化和坏死的症状。同一竹林林分中既有黄化叶片也有坏斑叶片。本文用非破坏、非接触的RGB图像分析法研究了这一现象。研究表明,室内拍摄的黄化竹单叶图像的G/R值与叶绿素计(SPAD)值之间呈紧密的正相关,平方回归相关系数0.961;与坏死斑面积率之间呈反逻辑斯蒂函数关系,平方回归相关系数0.958。用RGB图像分析法不仅可以估测叶片的黄化程度而且可也估测叶片的坏死斑面积。研究还发现,光线差异较大时拍摄的图片,相同叶片的G/L值的方差小于G/R值的方差值,尤其是绿色叶片。与G/R相比,黄化叶片的G/L值得到了与SPAD更紧密的相关性。室外拍摄的竹林冠分析表明,光线差别较大的图像G/L值与林分距海岸的距离的相关性也高于G/R值。     

干旱处理对侧柏和油松幼苗相对含水量和叶绿素含量变化的影响

以1年生的侧柏和油松幼苗为研究对象,采用盆栽的方式,利用干旱胁迫方式对幼苗的叶片相对含水量和叶绿素含量进行测定。结果表明,随着干旱程度的加剧,侧柏和油松幼苗的叶片相对含水量和叶绿素含量都呈下降趋势,两种树苗两个指标的测定结果都是以油松幼苗的下降最低,抗旱性最好。     

适用于表征古树衰老的生理指标

随着古树的衰老,代谢水平逐渐下降,多种酶趋于降解,营养物质合成速率降低,叶绿体和线粒体活力降低,明显出现器官水平上的程序化细胞死亡。本文概述近20年来国内外对古树叶片超微结构、叶绿素含量、蛋白质含量、活性氧防御系统、矿质营养元素等生理指标的检测和分析结果,旨在对古树的衰老检测和复壮提供理论依据和切实可行的方法。     

遮光对野鸦椿幼苗生长和光合生理特性的影响

为了解不同光照条件下野鸦椿幼苗的生长发育状况和光合生理特性,探讨野鸦椿幼苗生长发育的最佳光照条件。采用遮光方式模拟不同光照强度(全光照,遮光30%、60%和90%),研究野鸦椿幼苗的生长、生物量、光合色素含量、生理指标和光合日变化等光合特性的响应规律。结果表明:随着遮光程度的增加,野鸦椿幼苗的生长量均高于对照,以遮光60%的苗高、地径、根长、根幅的增幅最大;遮光30%、60%处理下其生物量积累较多,植株长势良好,叶色较深;遮光处理后,野鸦椿幼苗的叶绿素a、叶绿素b及叶绿素总量(Chla+Chlb)的含量增加,叶绿素a/b值降低;遮光处理使野鸦椿幼苗叶片可溶性蛋白含量降低,使叶片可溶性糖含量增加;遮光30%、60%处理条件下,叶片中MDA的含量显著低于全光照和遮光90%;随着遮光程度的加强,光合速率不断下降,以遮光30%处理下光合速率较高。因此,在育苗生产中,建议有效辐射强度保持在遮光率为30%~60%的范围,可培育出优良健壮的野鸦椿苗木。     

Changes in photosynthesis and leaf characteristics with tree height in five dipterocarp species in a tropical rain forest

Variations in leaf photosynthetic, morphological and biochemical properties with increasing plant height from seedlings to emergent trees were investigated in five dipterocarp species in a Malaysian tropical rain forest. Canopy openness increased significantly with tree height. Photosynthetic properties, such as photosynthetic capacity at light saturation, light compensation point, maximum rate of carboxylation and maximum rate of photosynthetic electron transport, all increased significantly with tree height. Leaf morphological and biochemical traits, such as leaf mass per area, palisade layer thickness, nitrogen concentration per unit area, chlorophyll concentration per unit dry mass and chlorophyll to nitrogen ratio, also changed significantly with tree height. Leaf properties had simple and significant relationships with tree height, with few intra- and interspecies differences. Our results therefore suggest that the photosynthetic capacity of dipterocarp trees depends on tree height, and that the trees adapt to the light environment by adjusting their leaf morphological and biochemical properties. These results should aid in developing models that can accurately estimate carbon dioxide flux and biomass production in tropical rain forests.     

基于k-mean聚类与灰度梯度最大熵的树木图像分割

提出一种基于k-mean聚类与灰度-梯度最大熵的树木图像分割算法,将要处理的树木彩色图像在RGB颜色空间下进行基k-mean聚类,通过选取合适的类参数实现初分割.由于灰度-梯度空间清晰地描绘图像中各个像素点的灰度、梯度的分布规律及图像目标与背景之间的边缘情况,采用灰度-梯度最大熵算法进行精分割,结合形态学后处理提取图像边缘最终将获得更理想的独立目标图像.与二维最大熵分割方法比较的实验结果表明,灰度-梯度最大熵算法提高了树木图像分割的准确度.     

Photosynthetic acclimation to light changes in tropical monsoon forest woody species differing in adult stature

We studied morphological and physiological leaf and whole-plant features of seedlings of six late-successional woody species common in the Xishuangbanna lowland rain forest in southwest China. Study species differed in adult stature and shade tolerance and included the shrubs Lasianthus attenuatus Jack and Lasianthus hookeri C.B. Clarke ex Hook. f.; the sub-canopy species Barringtonia macrostachya (Jack) Kurz and Linociera insignis C.B. Clarke; the canopy tree Pometia tomentosa (Blume) Teijsm. & Binn.; and the emergent species Shorea chinensis (Wang Hsie) H. Zhu. After 1 year of growth in low light (4.5% full sun), seedlings were transferred to high light (24.5% full sun) to investigate acclimation responses of existing leaves to forest gap opening and to determine whether seedling capacity for acclimation is a limiting factor in its natural regeneration. Leaves of the shrub species are shade-adapted, as indicated by their low photosynthetic capacity, efficiency in using sunflecks, low stomatal density, low Chl a/b ratio and high spongy/palisade mesophyll ratio. The shrub species utilized sunflecks efficiently because they had a short photosynthetic induction time and low induction loss. In all species, transfer of seedlings to high light resulted in a substantial initial reduction in the dark-adapted quantum yield of photosystem II (variable chlorophyll fluorescence/maximum chlorophyll fluorescence; Fv/Fm) at midday. Predawn Fv/Fm of the taller species did not change greatly, but predawn Fv/Fm of the shrub species decreased significantly without complete recovery within 25 days of transfer to high light, indicating chronic photoinhibition and damage to the previously shade-adapted leaves. Maximum net photosynthetic rate and dark respiration of the four taller species increased considerably after transfer to high light, but not in the shrub species. Similar trends were observed for the number of newly formed leaves and relative height growth rate. We conclude that the shrubs L. hookeri and L. attenuatus have limited potential for developmental and physiological acclimation to high light, which explains their absence from forest gaps. Compared with the shrub species, the taller tree species, which are more likely to experience high light during their life span, showed a greater potential for light acclimation. Physiological differences among the four tree species were not consistent with differences in adult stature.     

遮阴处理对华北落叶松幼苗生长的影响

对2年生落叶松幼苗进行不同的遮阴处理,测定华北落叶松叶片内可溶性糖、蛋白质、叶绿素的含量,结果表明：伴随着遮阴程度的增加,可溶性糖与蛋白质含量相应减少。与此同时,为了保护光合作用的正常进行,叶绿素b的含量逐渐增多。华北落叶松幼苗在生长过程中需要充足的光照,但适度的遮阴可促进光合作用的高效进行。     

三种观赏竹抗旱生理指标的研究及其综合评价

可控条件下研究了三种观赏竹铺地竹、平安竹、小佛肚竹在干旱胁迫下的生理指标变化,即叶片叶绿素、SOD、M DA、质膜透性的含量的变化。根据这些生理生化指标进行了抗旱性综合评价,结果为:平安竹>小佛肚竹>铺地竹。这一结果与三种观赏竹的实际表现是一致的。     

Use of thermal imaging to determine leaf conductance along a canopy gradient in European beech (Fagus sylvatica)

Using an infrared camera, we measured the leaf temperature across different canopy positions of a 23-m-tall deciduous forest tree (Fagus sylvatica L.) including typical sun and shade leaves as well as intermediate leaf forms, which differed significantly in specific leaf area (SLA). We calculated a temperature index (I(G)) and a crop water stress index (CWSI) using the surface temperatures of wet and dry reference leaves. Additional indices were computed using air temperature plus 5 °C (I(G)?+?5, CWSI?+?5) as dry references. The minimum temperature of the wet leaf and the maximum temperature of the dry leaf proved to be most suitable as reference values. We correlated the temperature indices with leaf area-related conductance to water vapor (g(L)) using porometry at the leaf level and using xylem sap flow at the branch level. At the leaf and at the branch level, I(G) and CWSI were equally well suited as proxies of g(L), whereas the relationships of I(G)?+?5 and CWSI?+?5 with g(L) were only weak or even insignificant. At the leaf level, the correlations of I(G) and CWSI with g(L) were significant in all parts of the crown. The slopes of g(L) vs. I(G) and CWSI did not differ significantly among the crown parts; this indicates that they were not influenced by SLA or irradiance. At the branch level, close correlations (r?>?0.8) were found between temperature indices and g(L) across the crown. These results demonstrate that satisfactory relationships between temperature indices and g(L) can be established in tall trees even in those canopy parts that are exposed to relatively low levels of irradiance and exhibit relatively low values of g(L).     

配方施肥对椿叶花椒苗木生长和生理指标的影响

通过N、P、K 3因素3水平的正交试验,探索配方施肥对盆栽椿叶花椒苗木生长及生理指标的影响.结果表明:(1)不同比例的N、P、K肥配施后,处理4至处理9对苗木各项指标均有极显著的影响,处理4有利于椿叶花椒苗木地径的增长,处理6对苗木的苗高增长最明显,处理5有利于生物量的积累,处理9有利于苗木叶片叶绿素含量、光合速率的提高;(2)N元素对椿叶花椒苗木生长和生理效应的影响极为显著,PK的影响很小;(3)根据N、P、K肥的施用量和苗木各项生长和生理指标测定值进行了二次函数关系方程的模拟,可据此分别求得各指标最大收获量所对应的合理施肥量.     

模拟酸雨对元宝枫幼苗生理及叶绿素荧光参数的影响

为了探明元宝枫的生理及叶绿素荧光参数对模拟酸雨胁迫的响应特征,以2年生元宝枫幼苗为研究对象,采用pH值分别为5.6、4.0、3.0、2.0的模拟酸雨处理0、15、30d后,分别测定了叶片脯氨酸、丙二醛、质膜透性等生理指标及叶绿素荧光参数。试验结果表明:1)pH值为4.0的酸雨处理初期,元宝枫叶片未出现伤害症状,处理后期叶片上出现了极少量的斑点,而pH值分别为3.0和2.0的酸雨胁迫下元宝枫叶面均出现了明显的伤斑,且随着酸雨胁迫时间的持续,酸害指数不断增大;2)随着酸度的增大,元宝枫叶片的叶绿素相对含量(SPAD)逐渐减少,尤其在pH值分别为3.0和2.0的酸雨处理下叶片的SPAD含量均显著低于对照;3)随着酸度的增大,元宝枫叶片中脯氨酸、丙二醛含量和质膜透性均呈上升趋势,但胁迫时间不同,各处理与对照间的差异显著性也不同;4)随着酸度的增大,元宝枫叶片的PSⅡ原初光能转化效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、以吸收光能为基础的性能指数(PIabs)、以单位面积为基础的性能指数(PIcs)均逐渐变小。当胁迫时间分别为0和15d时,pH值为4.0的酸雨处理下叶片的Fv/Fm值和PIabs与对照间均无显著差异,在pH值分别为3.0和2.0的酸雨处理下叶片的Fv/Fm值和PIabs均显著低于对照。研究结果表明:轻度酸雨(pH值为4.0)胁迫下,元宝枫植株渗透调节物质、叶绿素含量、叶绿素荧光参数的变化均不大,而其他处理尤其在重度酸雨(pH值为2.0)处理下,元宝枫植株的生长发育受到了严重的影响。     

Tolerance of Japanese larch to drought is modified by nitrogen and water regimes during cultivation of container seedlings

Improving drought tolerance of container seedlings of Japanese larch is of high importance to afforestation. We hypothesized that adequate nitrogen (N) and limited water supply would increase the tolerance of container seedlings to water-deficit stress, circumventing photoinhibition, by means of (i) enhanced photosynthetic capacity with higher leaf N and (ii) decreased water loss from leaves with lower biomass allocation into aboveground parts. Container seedlings of Japanese larch were grown under the treatment combinations of adequate (+?N: 300 mg N container^?1) or limited (??N: 150 mg N container^?1) N and adequate (+?W: daily irrigation) or limited (??W: twice-a-week irrigation) water. Then, seedlings were subjected to a progressive drought treatment. Higher leaf N was observed in container seedlings grown under?+?N and???W. During progressive drought, lower stomatal conductance and net photosynthetic rate were observed in leaves with higher leaf N at a given predawn leaf water potential. Furthermore, the maximum efficiency of PSII photochemistry (F_v/F_m) was lower in leaves with higher leaf N, suggesting that higher leaf N might impair intrinsic tolerance to drought at the leaf level contrary to expectations. Conversely,???N and???W seedlings with lower shoot biomass delayed soil drying as a whole-plant response via a reduction in leaf transpiration, leading to delayed photoinhibition as indicated by a decline in F_v/F_m. To circumvent stress at the initial stage of water deficit, lower leaf N via limited N regime and smaller shoot biomass driven by limited N and water regimes would be important.

     

Foliar temperature tolerance of temperate and tropical evergreen rain forest trees of Australia

Australian rain forests extend from tropical climates in the north to temperate climates in the south, providing an opportunity to investigate physiological responses to temperature of both temperate and tropical species within the same forest type. Eight, rain forest canopy tree species were selected to cover the 33 degrees latitudinal range of rain forests in eastern Australia. Temperature tolerance was measured in 6-year-old plants grown in a common environment, by exposing leaves to a series of high temperatures during late summer and a series of freezing temperatures during midwinter. Damage was evaluated based on chlorophyll fluorescence measurements made 2 h after exposure and by visual assessment of leaf damage made a week after exposure. Leaves of the tropical species were more heat tolerant and less frost tolerant than leaves of the temperate species, which is consistent with their climate distributions. In contrast, the temperature tolerance of the photosynthetic apparatus was unrelated to climate in a species' native habitat. However, the tropical species underwent significant photoinhibition during winter. All species maintained the integrity of the photosynthetic apparatus and avoided tissue damage over a similar span of temperatures (about 60 degrees C), reflecting the similar annual temperature ranges in Australia's temperate and tropical rain forests. Chlorophyll fluorescence measurements and visual assessment of leaf damage provided different estimates of the absolute and relative temperature tolerances of the species, thus emphasizing the importance of a direct assessment of tissue damage for determining a species' temperature tolerance.     

A recommended rate for application of Chaetomium globosum ND35 fungus fertilizer on poplar plantations in China

Previous studies showed that Chaetomium globosum ND35 fungus fertilizer can improve the microbial community structure and enzyme activities of replanted soil.However, it remains unclear whether can improve the physiological and ecological characteristics of plants under successive rotation.In this study, we investigated the photosynthetic, physiological, and biochemical indexes including photosynthetic parameters, chlorophyll fluorescence, and chlorophyll content of 1-year-old poplar seedlings under seven different doses(range from 0 to1.67 g kg~(-1)) of C.globosum ND35 fungus fertilizer to study the effects of fungus fertilizer on photosynthesis of Poplar.Our results showed that:(1) With increasing application of fungus fertilizer in replanted soil, chlorophyll content of poplar leaves(Chl) increased, while physiological indexes such as electron transport rate(ETR),net photosynthetic rate(P_n), quantum efficiency(U),nitrate reductase(NR) activity and root vigor initially increased and then declined.Meanwhile, heat dissipation that depended on the xanthophyll cycle declined and nonphotochemical quenching(NPQ) initially increased and then decreased.When the dose of C.globosum ND35 fungus fertilizer was 0.67 g kg~(-1)(T3) and 1.00 g kg~(-1)(T4), excess light energy of photosynthetic apparatus was reduced, and photosynthetic apparatus distributed more light energy to the direction of photochemical reactions,which improved the efficiency of energy use.Plant height and biomass of leaves, stems, and roots were maximum at T3.We conclude that applying appropriate amounts of C.globosum ND35 fungus fertilizer can improve root physiological activity and capacity for use of light by poplar leaves.This can improve the operating states of the photosynthetic apparatus and lead to increased photosynthetic efficiency of poplar leaves and accumulation of dry matter.This suggests a strategy to alleviate the successive rotation obstacle of soil nutrient depletion.     

低温胁迫下羊蹄甲和洋紫荆家系叶片相对电导率的变化

羊蹄甲Bauhinia purpurea和洋紫荆Bauhinia variegata是羊蹄甲属常见的景观树种,为研究其不同家系的抗寒能力,利用电导法分别对半年生实生苗进行人工低温胁迫试验。结果表明:随着低温胁迫的加重,各家系的叶片相对电导率整体呈上升趋势,且不同家系叶片的相对电导率增长速率不同,表明低温胁迫下各家系叶片的质膜受损程度不同。结合其形态特征变化和后期恢复速度,发现羊蹄甲Y15、洋紫荆G48、G26、G34家系的叶片相对电导率上升幅度较小,低温胁迫后恢复生长情况良好,表明其抗寒性较强。