Aboveground biomass and litterfall ofPinus pumila scrubs growing on the Kiso mountain range in central Japan

Aboveground biomass and litterfall ofPinus pumila scrubs, growing on the Kiso mountain range in central Japan, were investigated from 1984 to 1985. The biomass of two research plots (P1 and P2) with different scrub heights was estimated by two methods, the stratified clip technique and the allometric method. Aboveground total biomass estimated by the latter method reached 181 ton d.w. ha⁻¹ in P1 and 132 ton d.w. ha⁻¹ in P2. Creeping stems contributed to about half of the total biomass. Although estimates of woody organs differed between the two plots, leaf biomass estimates were almost the same at 15.5 ton d.w. ha⁻¹. The canopies of the twoP. pumila scrubs were characterized by a large mean leaf area density of 5.0 m² m⁻³. Despite this large area density, relatively moderate attenuation of light intensity was observed. Specific leaf area generally increased with reduced leaf height. Annual total litterfall was estimated to be 3.60 ton d.w. ha⁻¹ yr⁻¹ in P1 and 2.39 ton d.w. ha⁻¹ yr⁻¹ in P2. Annual leaf fall in both plots was approximately 2.0 ton d.w. ha⁻¹ yr⁻¹. Leaves fell mainly in early autumn. Annual loss rates of branches, estimated as the sum of annual branch litterfall and the amount of newly formed attached dead branches, were 0.29 ton d.w. ha⁻¹ yr⁻¹ in P1 and 0.37 ton d.w. ha⁻¹ yr⁻¹ in P2.     

Dynamics and dry matter production of belowground woody organs ofPinus pumila trees growing on the Kiso mountain range in central Japan

Size, biomass and spatial distribution patterns of belowground woody organs ofPinus pumila trees were investigated. Dry weight estimates of five sample trees were between 14 and 36 kg tree⁻¹. Belowground stems accounted for about 32% of the total tree weight. However, the belowground stems had extensive barkless portions, indicating that the decomposition of dead belowground stems was an important source of organic matter in the soil. The, basal diameters of adventitious roots tended to become smaller as their orginating positions neared the ground surface. It was suggested thatP. pumila trees regenerate by successively producing adventitious roots from their buried stems and moving down the slope.     

Abundance patterns of soil micro-arthropods at aPinus pumila scrub in an alpine range of central Japan

Seasonal changes in abundances of major soil micro-arthropods were assessed at aPinus pumila scrub in an alpine range of central Japan during a period with no snow coverage. The total abundance showed a peak in late August, reaching no less than 140 000 m⁻², which was comparable to that in an evergreen coniferous plantation in the cool-temperate zone. Collembola was the most dominant group of soil micro-arthropods, comprising about 50% of the total, followed by oribatid mites (Acari [O]) occupying 20%. Annual mean air temperature was no more than 2.1 °C and the daily fluctuation in temperature was less in soil layers. The thickness of the A₀ layer reached 9–10 cm and soil organic matter accumulation was estimated to be 45–58 ton dry weight ha⁻¹. The large amount of litterfall and organic matter accumulation in the soil, comparable to those of sub-alpine evergreen coniferous forests, and a lower decomposition rate due to severe environmental conditions, suggest the relative importance of litter processing by soil micro-arthropods such as Collembola and Acari, especially in alpine regions.     

Photosynthesis and respiration ofPinus pumila needles in relation to needle age and season

Rates of net photosynthesis and dark respiration were measured for detached needles ofPinus pumila trees growing on the Kiso mountain range in central Japan in 1987. Dependency of photosynthesis on light and temperature was examined in relation to needle age and season. The light saturation point of net photosynthesis was lower in 3- and 4-yr-old needles than that in current (flushed in 1987), 1- and 2-yr-old needles.P _nmax, net photosynthetic rates at 1000 μmol m⁻² s⁻¹ and 15°C, of needles from 1- to 4-yr-old generally decreased with needle age.P _nmax of 1- to 4-yr-old needles became higher in August than in other months, andP _nmax of current needles did so in September. Current needles showed high respiration rates (at 15°C) only in August. Optimum air temperatures for net photosynthesis at 1000 μmol m⁻² s⁻¹ were between 10 and 15°C for current and 1-yr-old needles. The temperature coefficient of dark respiration rates was 2.3–3.3 for current needles from August to October, and 2.2 for 1-yr-old needles in mid-July.     

Genetic structure within a Japanese stone pine (Pinus pumila regel) population on Mt. Aino-dake in central Honshu, Japan

In previous investigations, natural layering of Japanese stone pine (Pinus pumila) was suggested by the occurrence of adventitious roots. However, there is no genetic evidence so far that this species actually produces offspring by natural layering. We, therefore, investigated clonal structure and spatial genetic structure within a 38×18 m plot on Mt. Aino-dake, using allozyme, random amplified polymorphic DNA (RAPD), and inter-simple sequence repeat (ISSR) analyses. We found 24 genets, with stems found to be genetically identical in multiple tests, which extended later-ally against the direction of the slope, indicating that there were clonal structures originating from elongation of ramified stems and subsequent natural layering. The results suggest, however, that less than one third of the 200 stems analyzed from this site were clonaly propagated. We also analyzed spatial genetic structure by spatial autocorrelation. Many of the spatial autocorrelation coefficients were significantly positive in short distance classes. We concluded that the species has genetic structures which largely originate from clonal propagation and avian seed dispersal.     

开放式空气二氧化碳浓度增高对小麦物质生产与分配的影响

2001—2003年,利用农田开放式空气CO₂浓度增高 (FACE) 技术平台,以冬小麦宁麦9号为供试材料,研究开放式条件下CO₂浓度增高对小麦整个生育期干物质生产与分配的影响.结果表明：与对照相比,FACE处理使小麦播种-越冬始期的干物质生产量略有增加（10.8%),使越冬始期-拔节期、拔节期-孕穗期、孕穗期-抽穗期显著增加,分别增加了31.6%、40.5%、27.2%,使抽穗期-成熟期略有减少(-5.5%),使成熟期生物产量显著增加(13.6%);FACE处理对小麦播种-越冬始期的平均叶面积系数(LAI)和净同化率(NAR)均无显著影响,但使越冬始期-抽穗期LAI显著增加,NAR稍有增加,使抽穗期-抽穗后20 d NAR显著下降;FACE处理使不同生育时期叶片占全株质量的比例下降,而使茎鞘占全株质量的比例增加;FACE小麦抽穗期和成熟期茎鞘可溶性糖和淀粉含量及总量均明显增加.     

Aboveground net primary production dynamics in a northern Chihuahuan Desert ecosystem

Aboveground net primary production (ANPP) dynamics are a key element in the understanding of ecosystem processes. For semiarid environments, the pulse-reserve framework links ANPP to variable and unpredictable precipitation events contingent on surficial hydrology, soil moisture dynamics, biodiversity structure, trophic dynamics, and landscape context. Consequently, ANPP may be decoupled periodically from processes such as decomposition and may be subjected to complex feedbacks and thresholds at broader scales. As currently formulated, the pulse-reserve framework may not encompass the breadth of ANPP response to seasonal patterns of precipitation and heat inputs. Accordingly, we examined a 6-year (1999–2004), seasonal record of ANPP with respect to precipitation, soil moisture dynamics, and functional groups in a black grama (Bouteloua eriopoda) grassland and a creosotebush (Larrea tridentata) shrubland in the northern Chihuahuan Desert. Annual ANPP was similar in the grassland (51.1 g/m²) and shrubland (59.2 g/m²) and positively correlated with annual precipitation. ANPP differed among communities with respect to life forms and functional groups and responses to abiotic drivers. In keeping with the pulse-reserve model, ANPP in black grama grassland was dominated by warm-season C₄ grasses and subshrubs that responded to large, transient summer storms and associated soil moisture in the upper 30 cm. In contrast, ANPP in creosotebush shrubland occasionally responded to summer moisture, but the predominant pattern was slower, non-pulsed growth of cool-season C₃ shrubs during spring, in response to winter soil moisture accumulation and the breaking of cold dormancy. Overall, production in this Chihuahuan Desert ecosystem reflected a mix of warm-temperate arid land pulse dynamics during the summer monsoon and non-pulsed dynamics in spring driven by winter soil moisture accumulation similar to that of cool-temperate regions. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Biomass and net production in a bambooPhyllostachys bambusoides stand

Biomass and net production were measured in aPhyllostachys bambusoides stand in Kyoto Prefecture, central Japan, which had carried out gregarious flowering in 1969 and has been recovering vegetatively. The culm density fluctuated around an average value of 12 040 ha⁻¹ during the research period (1985–91). Annual recruirment and mortality rates of culms were 1340 and 1133 ha⁻¹, respectively. The mean diameter at breast height increased from 7.28 cm in 1985 to 8.68 cm in 1991, and the biomass of culms increased from 71.3 to 111.6t ha⁻¹ over the same time period. Branch and leaf biomasses were almost constant, 10.0 and 9.4t ha⁻¹ on average, respectively. The leaf area index of the stand was 11.6 ha ha⁻¹, which is one of the largest values found in Japanese forests. The belowground biomass of 32.6t ha⁻¹ for rhizomes and 14.8t ha⁻¹ for fine roots resulted in the smaller ratio of aboveground parts to the root system (2.38) than those determined for forest stands. The amount of litterfall, excluding culms and large branches, was large (9.13t ha⁻¹ year⁻¹), corresponding to those measured in equatorial stands. The aboveground net production was 24.6t ha⁻¹ year⁻¹, larger than the average value reported for forest stands under similar weather conditions.     

Elevated atmospheric partial pressure of carbon dioxide and dry matter production of konjak (Amorphophallus konjac K. Koch)

Konjak (Amorphophallus konjac K. Koch) was grown under normal (350 bar) or enriched (700 bar) CO₂ partial pressure in glasshouses kept at 33/26 °C. Doubling the CO₂ partial pressure resulted in twice the yield of corm because the net CO₂ assimilation rate doubled and, due to the simple source-sink relationship, the increased production was partitioned to the corm. The response to CO₂ of assimilation by konjak is discussed in relation to its original habitat in the tropics.     

Structure and function of shisham forests in central Himalaya,India: dry matter dynamics

The biomass and net primary productivity (NPP) of 5- to 15-year-old Shisham (Dalbergia sissoo Roxb.) forests growing in central Himalaya were estimated. Allometric equations were developed for all above- and below-ground components of trees and shrubs for each stand. Understorey forest floor biomass and litter fall were also estimated in forest stands. The biomass (dry matter), forest floor biomass (standing crop litter), tree litter fall and NPP of trees and shrubs increased with increasing age of the forest stand, whereas the dry matter and herb NPP decreased significantly (P < 0.001) with increasing age of the forest. Total forest biomass and NPP ranged from 58.7 (5-year-old stand) to 136.1 t ha(-1) (15-year-old stand) and 12.6 (5-year-old stand) to 20.3 t ha(-1) year(-1) (15-year-old stand), respectively. Of these values, tree biomass accounted for 85.7 (5-year-old stand) to 90.1% (15-year-old) of total forest biomass, and tree NPP for 72.2 (5-year-old) to 82.3% (15-year-old) of total forest NPP. The biomass accumulation ratio (BAR) of the bole component (bole wood + bole bark) increased with increasing age of the forest stand. The bole BAR was 5.8 (5-year-old stand) to 7.9 (15-year-old stand). However, total BAR of the forest stand ranged from 5.5 (5-year-old) to 7.5 (15-year-old).     

Above- and belowground organic matter storage and production in a tropical pine plantation and a paired broadleaf secondary forest

The distribution of tree biomass and the allocation of organic matter production were measured in an 11-yr-old Pinus caribaea plantation and a paired broadleaf secondary forest growing under the same climatic conditions. The pine plantation had significantly more mass aboveground than the secondary forest (94.9 vs 35.6 t ha^-1 for biomass and 10.5 vs 5.0 t ha^{-1 for litter}), whereas the secondary forest had significantly more fine roots (⩽2 mm diameter) than the pine plantation (10.5 and 1.0 t ha^-1, respectively). Standing stock of dead fine roots was higher than aboveground litter in the secondary forest. In contrast, aboveground litter in pine was more than ten times higher than the dead root fraction. Both pine and secondary forests had similar total organic matter productions (19.2 and 19.4 t ha^-1 yr^-1, respectively) but structural allocation of that production was significantly different between the two forests; 44% of total production was allocated belowground in the secondary forest, whereas 94% was allocated aboveground in pine. The growth strategies represented by fast growth and large structural allocation aboveground, as for pine, and almost half the production allocated belowground, as for the secondary forest, illustrate equally successful, but contrasting growth strategies under the same climate, regardless of soil characteristics. The patterns of accumulation of organic matter in the soil profile indicated contrasting nutrient immobilization and mineralization sites and sources for soil organic matter formation.     

Structure and regeneration ofFraxinus spaethiana-Pterocarya rhoifolia forests in unstable valleys in the Chichibu Mountains,central Japan

The structure of temperate deciduous forests dominated byFraxinus spaethiana andPterocarya rhoifolia in V-shaped valleys in the Chichibu Mountains, central Japan was studied to clarify their dynamics, with special reference to disturbance. Forest structure and annual ring analysis revealed that the forests have been subjected to mass movement (mud flow) in the past. The size and age structure, and diameter growth curves, indicated thatF. spaethiana is relatively shade tolerant, long living and slow-growing, whileP. rhoifolia is less shade tolerant, short living, but fast growing.Pterocarya rhoifolia appears to depend on large-scale but rare disturbances.Fraxinus spaethiana establishes its seedlings on relatively unstable substrate in V-shaped valleys, but once established, they survive a long time with high shade tolerance. The dominance and coexistence of the two species may primarily depend on the intensity and frequency of geomorphological processes.     

Identification of a rust fungus onPinus pumila collected in the North Kurils, Russia

Morphological examination and PCR-RFLP analysis of the D1/D2 region in nuclear LSU rDNA were carried out to identify a rust fungus onPinus pumila collected in the North Kurils, Russia. Morphologically, the rust from the North Kurils was similar toPeridermium kurilense andEndocronartium sahoanum var.hokkaidoense in the spore surface structure, dimension and shape. In the RFLPs of the D1/D2 region it was identical toE. sahoanum var.hokkaidoense andE. sahoanum var.sahoanum, but distinct fromCronartium ribicola. Therefore, the rust fungus onP. pumila collected in the North Kurils was identified asE. sahoanum var.hokkaidoense. It was also clarified that a rust reported previously asP. kurilense was also identical withE. sahoanum var.hokkaidoense.     

基质水势对切花百合植株干物质分配影响的预测模型

干物质分配与转移是观赏植物外观品质形成的基础,受水分影响极大.本文以切花百合品种‘索邦’为试验材料,于2009年3月至2010年1月在南京的连栋温室内开展了不同定植期和不同水分处理的栽培试验,定量分析了不同定植期和不同水分处理条件下切花百合干物质分配和转移的变化规律,以及基质水势对百合地上部和地下部各器官(花、茎、叶、鳞茎、茎生根)干物质分配指数的动态影响,并确定了切花百合正常生长的临界基质水势,最终建立了基质水势对切花百合植株干物质分配影响的动态预测模型.结果表明:本文所建模型对百合各器官(花、茎、叶、鳞茎、茎生根)干质量的预测效果较好,模型对花、茎、叶、鳞茎、茎生根干质量的预测值与实测值之间的决定系数分别为0.96、0.95、0.86、0.95、0.85,预测相对标准误分别为19.2％、12.4％、19.4％、12.2％、31.7％.-15 kPa可作为切花百合‘索邦’水分管理的临界水势.     

Fungal succession in the early decomposition process of pine cones on the floor ofPinus densiflora forests

The fungal succession on pine cones on the floor ofPinus densiflora forest was investigated in the early decomposition process (within ca. 30% decrease in dry weight). The fungal flora was examined by both washing and surface-sterilization methods on artificially placed cones and naturally fallen cones. The decomposition rates of artificially placed cones were 0.081–0.082 yr^–1. On withered cones still attached to the tree,Pestalotiopsis spp. were dominant. These fungi also occurred with higher frequencies after cones had lain on the floor and on cones in the L and FH horizons.Xylaria sp. andPhomopsis sp., which seem to colonize the interior of the tissue, occurred with higher frequencies on the cones on the tree, but their occurrence frequencies decreased after cones had lain on the forest floor. Conversely,Mortierella spp. andTrichoderma spp. newly occurred or their occurrence frequencies increased on lying cones. Of these,Trichoderma koningii increased rapidly and showed high occurrence frequencies.Thysanophora penicillioides, which prefers coniferous substrates, showed higher occurrence frequencies in the early stages of lying on the forest floor. On cones lying on the floor, the fungal flora did not significantly change during the investigation period.     

温度、光辐射及水分对温室甜瓜幼苗干物质积累与分配的影响及其模拟模型

利用分期播种法和灌溉上限法,研究了温度、光辐射和水分等环境因子对温室甜瓜幼苗植株干物质积累与分配的影响,并基于积温学原理,综合环境其他因子,模拟建立了甜瓜幼苗受有效积温、日温差积累、光辐射积累等多因子驱动的干物质积累与分配模型．结果表明：周年不同播期,随着有效积温、光辐射积累及不同灌溉水分上限的变化,甜瓜幼苗期植株干物质积累和分配分别呈指数函数和二次抛物线函数变化,但不同播期及水分处理函数常数不同．综合分析认为,干物质积累和分配模型分别为有效积温驱动下的指数函数和二次抛物线函数,常数项均由日温差积累和光辐射积累驱动,它们之间为一次函数关系．验证结果表明,该模型能较为真实、客观地模拟植株干物质积累与分配变化过程,对甜瓜苗期生长分析与生产管理具有应用价值．     

Soil-productivity relationships and organic matter turnover in dry tropical forests of the Florida Keys

Soils and aboveground production in five types of upland forest in the Florida Keys were examined. Throughout the habitat gradient represented by these forest types, the soils were predominantly shallow and organic, forming in place directly on the limestone bedrock. However, the well-drained soils in the most productive broadleaved forests were deep enough to qualify as Histosols (Folists). Soils decreased in electrical conductivity and increased in nutrient content with increasing aboveground production. At 3–12 Mg ha^–1 yr^–1, production was within the range reported for dry tropical forests. Measured rates of decomposition were moderate or fast, and estimates of the organic C turnover of several soils based on their bomb radiocarbon signature were 100 years or less. In the face of these rapid turnover rates, we attribute the development of organic soils to the absence of mineral residues from weathering of the underlying limestone bedrock. Fast turnover of organic matter, and rapid and efficient cycling of nutrients are necessary to sustain the high production rates obtained on these shallow organic soils.     

基于源库生长单位的温室番茄干物质生产-分配模拟

为了量化研究温室番茄果穗间干物质的分配,提高温室番茄栽培的效益,采用源库生长单位的测定方法,将经典的单叶同化物生产模型与GreenLab模型相结合,构建了干物质向源库生长单位内茎节、叶片、果实分配的动态模型,利用越冬茬、早春茬和春夏茬温室番茄各器官的干物质测定数据对模型进行了验证.结果表明:所构建的模型模拟结果与实测结果吻合性较好,不同茬口同化物生产模拟值与实测值的回归方程斜率为0.93,R~2为0.92;源库生长单位内茎节、叶片、果实以及根系的模拟值与实测值间回归方程斜率在0.85～0.89之间,其相对误差(R_e)均值分别为5.3%、5.6%、8.1%和3.6%,说明模型的模拟准确度较高,可为不同茬口温室番茄栽培管理提供理论依据和决策支持.     

石灰岩山地优势种淡竹生物量分配的影响主因研究

该研究在江西省瑞昌市设置9个淡竹林样地,调查和测定了淡竹林密度、淡竹各构件的生物量和总生物量,以及土壤含水率、土层厚度、林下裸岩率、pH、电导率、全氮和全磷等7个土壤环境因子,并对竹林密度、土壤环境因子和淡竹生物量分配指标进行了相关分析和回归分析。结果表明：(1)密度与淡竹蔸比重相关系数r达0.66( P＝0.02<0.05),而与叶比重、枝比重、秆比重、鞭比重、根比重及根冠比均无显著相关关系;土壤环境因子与生物量分配指标有密切相关,环境主成分Z1与叶比重、秆比重及蔸比重均显著相关(P<0.05),Z2与鞭比重显著相关(P＝0.034<0.05)。(2)密度与土壤环境因子密切相关(P<0.05),控制土壤环境因子的偏相关分析显示密度与淡竹生物量分配不显著相关( P>0.05),而控制密度时,土壤环境因子与淡竹生物量分配仍有显著相关关系(P<0.05);逐步回归分析也验证了偏相关分析的结果,密度被排除出回归方程。分析认为,土壤含水率、土层厚度及土壤养分等环境因子是影响石灰岩山地优势种淡竹生物量分配的主因,密度对生物量分配的影响实为土壤环境因子的间接作用。该研究结果为石灰岩地区植被恢复提供了理论支撑。