Leaf non-structural carbohydrates and leaf dry weight per area in three altitudinal populations ofEspeletia schultzii WEDD

The leaf non-structural carbohydrate (NSC) content and total non-structural carbohydrate content (TNC) were measured on a dry weight basis and on a leaf area basis in three altitudinal (3100, 3550 and 4200 m a.s.l.) populations ofE. schultzii. The values of leaf dry weight per area (LWA) increase with altitude. The leaf non-structural carbohydrate content (expressed as g/kg dry weight) does not show statistically significant difference among populations, but the values expressed on an area basis (g/m²) show a statistically significant increase with altitude. Significant correlations were observed between LWA and TNC (r ²=0.65); insoluble carbohydrate (r ²=0.78); total soluble carbohydrate (r ²=0.53); reducing sugars (r ²=0.47) expressed on area basis. Correlations between LWA and NSC for any fraction and TNC on a dry weight basis were not significant. It appears that along this altitudinal gradient the leaf area is more affected than the leaf dry weight. Since the NSC is known to play a role in the freezing tolerance of plants, the results indicate that the freezing tolerance does not change among the populations along the gradient.     

不同退化程度高寒草甸高山嵩草的构件变化

对不同退化程度下高山嵩草的构件变化进行了初步研究.结果表明:随着退化程度的加剧,高山嵩草无性系复合主分蘖数、单分蘖数以及构件的叶片数均明显下降,退化程度加剧不利于高山嵩草的营养生长;除极度退化草地外,其余样地各构件的生物量大小依次是:根茎>根>叶>秆,并且随退化程度的加剧,各构件生物量显著下降;重度退化草地中,莎草科植物生殖枝数占植物群落总生殖枝的比例最大,每个有效生殖枝平均产生3.4粒种子.     

去叶对青杨雌雄植株生长和非结构性碳水化合物的影响

近年来,森林食叶害虫在全世界呈爆发趋势.树木的非结构性碳水化合物(NSC)如何响应叶片损失对其生长和生存至关重要.雌雄异株植物在维持森林生态系统稳定性方面扮演着重要角色.然而,目前对该类植物性别之间如何响应去叶的研究还比较少.本文以我国重要的经济和生态恢复树种青杨(Populus cathayana)为研究材料,比较了...     

氮添加与降雨变化对红砂幼苗非结构性碳水化合物的影响

非结构性碳水化合物(NSC)在植物体内的含量及分配对植物生长和存活至关重要。开展氮沉降和降雨变化对幼苗NSC影响的研究,为揭示干旱导致幼苗死亡机理及预测气候变化背景下幼苗自然更新及培育提供依据。本研究以1年生红砂幼苗为对象,测定了不同降雨(降雨减少(W-)、自然降水(W)和降雨增多(W+))和氮添加(N0(0 g N·m-2·a-1)、N1(4.6 g N·m-2·a-1)、N2(9.2 g N·m-2·a-1)、N3(13.8 g N·m-2·a-1))条件下红砂幼苗各器官NSC及其组分含量。结果表明:红砂幼苗各器官NSC含量为28.8～71.8mg·g-1,叶片含量最高,茎含量最低。氮添加和降雨变化对红砂幼苗叶片和根系淀粉及总NSC含量有显著影响,而对茎无显著影响。各降雨条件下,氮添加均促进了红砂幼苗叶片淀粉和总NSC累积,在降雨增加30%的条件下氮的促进效应更显著,中高氮(N2和N3)叶片淀粉与总NSC含量显著高于低氮水平(N1和N0);在低氮降雨减少30%(N1W-)处理下,红砂叶片淀粉和NSC含量最小,而根系淀粉和NSC含量最大,即低氮干旱胁迫下红砂可通过NSC在不同器官的重...     

Spatial variations in non-structural carbohydrates in stems of twelve temperate tree species

The radial, axial and inter-specific variations in concentrations and contents of non-structural carbohydrates (NSC) in stems were investigated for 12 Chinese temperate tree species. These species had contrasting leaf phenology (evergreen and deciduous) and wood types (non-, ring- and diffuse-porous wood). For each species, we sampled bark (periderm and phloem), outer wood (light-colored) and inner wood (dark-colored) at four heights along the stem (stump, breast height, crown base and mid-crown). Concentrations of total NSC (TNC, sum of sugars and starch), sugars and starch were much higher in bark than those in wood. On average, contents of sugars and starch accounted for 48 and 52 % of the TNC, respectively, and contents of TNC in bark, outer wood, and inner wood accounted for 34, 38, and 28 % of the stem total, respectively. Bark was the major pool of sugars in the stem (accounting for 50 % of the stem total on average), while outer wood was the major pool of starch (41 %). The concentration of sugars varied axially for all the conifers but did not for the broadleaved species. Mean concentrations of TNC, sugars and starch in stem varied by more than twofold among the species. However, there were no significant differences in these values for the species groups with different leaf phenology or wood types. Ignoring the radial, axial and inter-specific variations in NSC in stem would introduce large bias in estimating NSC storage at tree or ecosystem levels.     

Seasonal changes in non-structural carbohydrates and sucrose metabolism enzymes in two Sabina species

Evergreen plants need to store reserves to allow for their survival during the winter months and for new leaf growth in the following spring. In many of the tree species, these reserve functions are mainly carried out by starch, which is degraded to soluble carbohydrates during the dormant season to maintain active respiration and provide protection against freezing. In the present study, two evergreen woody plants, S. przewalskii Kom. (SP) and S. chinensis (Lin.) Ant.(SC), were used to investigate the patterns of seasonal variation in the concentrations of soluble sugars, sucrose, fructose and starch, and the activities of sucrose-phosphate synthase (SPS), sucrose synthase (SUSY), neutral invertase (NI) and soluble acid invertase (SAI). Foliar soluble sugar, sucrose, fructose, and starch concentrations were markedly higher in SC than in SP; moreover, the activities of SPS, SUSY, NI and SAI were also higher in SC than in SP. There were generally higher concentrations of soluble sugars, sucrose and fructose and SPS activities in the winter than in the summer for both Sabina trees, which was consistent with the necessity for protection against freezing; however, opposite results were found with regards to starch concentrations and the activities of SUSY, NI and SAI. In contrast with the activities of SUSY, NI and SAI, the negative correlation observed between SPS and air temperature was likely a reflection of its crucial role in the acquisition of freezing tolerance by sucrose metabolism in the winter. These results suggest that higher carbon reserves do not give S. chinensis (Lin.) Ant. a competitive advantage in tolerating cold temperatures and that only SPS, but not SUSY, NI and SAI, may play a positive role in freezing tolerance by increasing soluble sugar.     

Variation of non-structural carbohydrates in silver birch (Betula pendula Roth) wood

Non-structural carbohydrates in silver birch (Betula pendula Roth) wood were analysed in a 7-year-old clone and in five mature stems. The analysis was conducted to obtain more detailed information on seasonal fluctuation of these components and of the tree-to-tree variation and within stem variation. The sugars were analysed by GLC-MS. The smallest total soluble sugar amounts (consisting of sucrose, fructose, glucose, raffinose and myo-inositol) in young trees were measured during mid-summer (ca. 0.3%) and the largest while in dormancy (ca. 1.6% on wood dry weight basis). Raffinose was detected in autumn as a minor component. The proportion of monosaccharides and the amount of myo-inositol were largest during growth. Compared to other studies silver birch showed more evident seasonal fluctuation in soluble sugars than evergreen tree species. The sugar amount in mature stems was approximately at the same level as in young trees that had the same felling time. Tree-to-tree variation in the non-structural carbohydrates in the mature wood was fairly large. However, the amount of total soluble sugars, sucrose and glucose showed significant variation within the stem. The amount of these sugars was largest in samples that were taken close to the cambium. Starch was also detected close to pith. According to the heartwood definition and starch measurement results in this paper, it could be stated that silver birch does not form heartwood.     

Growth responses and non-structural carbohydrates in three wetland macrophyte species following submergence and de-submergence

We investigated the responses of growth and non-structural carbohydrates to submergence and de-submergence in three wetland macrophyte species. Survival rate, recovery ability, and soluble sugar and starch contents of flood-tolerant Polygonum hydropiper and of flood-sensitive Phalaris arundinacea and Carex argyi from Dongting Lake wetlands were investigated after 20, 40, and 60 days of complete submergence without light and 10 days after de-submergence. Plant dry weight and soluble sugar and starch contents decreased in all species during the submergence period. The decreases were slowest in P. hydropiper, intermediate in C. argyi, and most rapid in P. arundinacea. After 60 days of submergence, survival rates were 100, 50, and 0 % in P. hydropiper, C. argyi, and P. arundinacea, respectively. After recovery, plant dry weight increased in P. hydropiper and in C. argyi, but decreased in P. arundinacea. Compared to pre-submergence, soluble sugar contents generally increased and then remained relatively constant after recovery in all species, while starch content increased in P. hydropiper and decreased in P. arundinacea with increasing submergence time. For C. argyi, starch content decreased after recovery from the 20-day submergence, but increased after recovery from the 40- and 60-day submergences. These data illustrate mechanisms behind the flood tolerance of P. hydropiper and the sensitivity to flooding in P. arundinacea and C. argyi. These mechanisms include lower consumption and quicker accumulation of non-structural carbohydrates in flood-tolerant plants.     

小麦非结构性碳水化合物分配对水分胁迫的生理响应

以‘西旱2号’小麦为试材,采用水分胁迫和复水处理方法,研究了小麦发育过程中不同水分胁迫下非结构性碳水化合物(NSC)在小麦旗叶、茎、叶鞘等器官中的动态变化,以及籽粒中碳代谢相关酶(可溶性淀粉合成酶SSS和淀粉粒结合态合成酶GBSS)活性的变化.结果表明:不同程度水分胁迫对小麦旗叶、茎、叶鞘等器官中蔗糖含量无显著影响.随水分胁迫的深入,花后12～ 18 d旗叶中淀粉含量显著增加;水分胁迫缩短了花后茎和叶鞘中淀粉的积累时间,抑制了茎中淀粉的转化和分配;而叶鞘中淀粉的积累逐渐增大,在中度水分胁迫下积累提前终止.在水分胁迫初期,各营养器官中的NSC含量为旗叶＞茎＞叶鞘;随着水分胁迫的深入,各营养器官中的NSC含量为茎＞旗叶＞叶鞘.小麦主要营养器官中NSC的分配速率及主要代谢酶的变化可能是小麦对水分胁迫的一种生理调节反应.     

Seasonal changes and altitudinal variation in deer fecal pellet decay

Surveying dung pellet groups to estimate population size requires knowledge of the dung decay rates in different environmental conditions. We evaluated seasonal and elevational differences in the decay rates of fresh deer pellets in the Ashio–Nikko Mountains, Japan. At each of four sites (1,500, 1,200, 900, and 600 m above sea level), we set out four replicates of 50 fresh deer pellets each month from September 2008 to August 2009. Dung pellet groups were evaluated after 24 h and again monthly. We also monitored the dung beetle fauna monthly using pitfall traps. Dung beetle activity was positively correlated with temperature, and the rate of dung decay was strongly correlated with dung beetle dry weight. Decay was most rapid during summer and at lower altitudes; pellets set out during winter did not decay until the following spring. Resource managers who use dung surveys to estimate population sizes in mountainous regions should consider the decay rates at different altitudes.     

辽东栎(Quercus liaotungensis )叶特性沿海拔梯度的变化及其环境解释

植物对环境的适应一直是生态学研究的核心问题之一。山地由于海拔剧烈变化造成显著的环境差异,成为研究植物对环境适应性变化的理想对象。为阐明辽东栎（Quercus liaotungensis Koidz.）叶对环境的适应性变化,在北京东灵山地区辽东栎海拔分布范围（1000~1800m）内研究了叶特性的变化规律及其与地形和土壤养分的关系。回归分析发现：辽东栎气孔密度、气孔长度和叶面积随海拔的升高呈现曲线变化形式。在海拔约1400m处,气孔密度最小而气孔长度和叶面积最大;气孔密度和长度成反比;叶长宽比没有明显变化;叶绿素（a＋b）含量和单位干重叶氮、磷和钾含量沿海拔梯度呈上升趋势,同时叶绿素含量和叶氮含量有较弱的正相关。偏相关分析显示：叶绿素含量和坡位有显著的相关关系,叶磷含量与坡度关系显著,但叶养分与土壤养分之间未表现出明显的相关关系;地形和土壤养分与气孔密度、长度和叶面积等形态指标的关系均不显著。方差分析表明上坡位与中、下坡位的叶绿素含量有显著差异,上坡位的叶绿素含量最高。辽东栎大部分叶特性在其海拔分布范围内有显著的变化,并且形态特征和养分特征的变化形式不同,海拔1400m左右是辽东栎叶形态特征变化最显著的范围。这些叶特征的变化与土壤养分的关系不明显。     

Effects of ozone and Phytophthora citricola on non-structural carbohydrates of European beech (Fagus sylvatica) saplings

A lysimeter study was performed to monitor long term effects of chronic ozone enrichment on saplings of European beech (Fagus sylvatica L). After 3 years of ozone exposure a root infection with Phytophthora citricola Swada was established in the fourth year to study the interaction between elevated ozone and the root infection on the carbon budget of beech saplings. By using quantitative PCR no differences in root infection with P. citricola were observed between the ozone treatments. In contrast to the first 3 years of ozone exposure, sucrose and starch concentrations in leaves were diminished in ozone treated plants in the fourth year. The root infection reduced sucrose concentrations in leaves. Starch reserves of the heterotrophic biomass were not affected by any treatments. Thus 4 years of ozone exposure and 1 year of P. citricola root infection had only limited effect on carbohydrate metabolism in beech saplings.     

Seasonal dynamics of non-structural carbohydrates in two species of mediterranean sub-shrubs with different leaf phenology

The seasonal dynamics of non-structural carbohydrates in the woody organs of two co-existing mediterranean sub-shrubs were analyzed. The two species show different leaf phenology during summer: Linum suffruticosum, maintains many of its green leaves, while Lepidium subulatum sheds most of its leaves. These different leaf phenologies are related to different strategies with regard to summer stress. The maintenance of leaves in Linum is related to its stress tolerance while Lepidium avoids stress by shedding its leaves. The main objectives were to: (1) determine the differences in the seasonal dynamics of non-structural carbohydrates among the main woody organs of both species; (2) verify if differences in the leaf phenology, and hence in the strategy with regard to summer drought, lead to different seasonal patterns of carbohydrate storage and use between the two species; (3) compare the seasonal dynamics of carbohydrates of the two studied sub-shrubs with those of mediterranean trees and shrubs previously reported in the literature. The concentration of soluble sugars (SS), starch and total non-structural carbohydrates (TNC) were assessed monthly, over 17 months, in the main roots, stems and the transition zone between root and shoot systems of both species. Starch storage capacity and SS, starch and TNC pools were calculated. The seasonal pattern of carbohydrate accumulation was similar among the woody organs analyzed, but it differed with those reported for mediterranean trees and shrubs. The two species showed different pools and seasonal patterns of non-structural carbohydrate concentrations in its woody organ, which corresponded to their different extent of leaf shedding. The stress-avoider Lepidium accumulated starch during spring shoot growth as a carbon store for summer respiration and had low pools of SS, whereas the stress-tolerant Linum increased SS during summer drought to maintain photosynthetic activity during summer and had low starch pools and storage capacity. However, irrespective of their different leaf shedding patterns, both species had a similar relative variation of their TNC concentration, which contrasts with previous results on deciduous and evergreen woody species.     

The effect of lidocaine on lysophosphatidylcholine-induced cardiac arrhythmias and cellular disturbances

The production of arrhythmias in the isolated heart by perfusion with lysophosphatidylcholine has been well documented. However, the role of the lysophospholipid as a physiological factor in the generation of cardiac arrhythmias is not clear. In this study, a pharmacological approach was used to delineate the physiological significance of lysophosphatidylcholine during this cardiac dysfunction. Lidocaine (5-20 mg/L) was found to be effective in the protection of the isolated rat heart from the lysophospholipid-induced arrhythmias at pharmacological concentrations. The effect of lidocaine in the protection of lysophospholipid-induced membrane dysfunction was studied with red blood cells. Lidocaine (2 mg/mL) protected red blood cells from hemolysis in the presence of lysophosphatidylcholine. Lidocaine did not inhibit the binding of the lysophospholipid to the red cell membrane, but inhibited hemolysis in a manner similar to cholesterol. The results are consistent with the postulate that lysophosphatidylcholine is a physiological factor in the pathogenesis of cardiac arrhythmias during myocardial ischemia.