能源植物芒草研究进展与综合利用现状

芒草是一类多年生的C4草本植物,因其具有生物量大、纤维素含量高、灰分低、热值高、适应性强、生产成本低等诸多优点被认为是目前最具开发潜力的高产纤维类能源植物之一,因而成为国内外关注和研究的热点。综述了国内外能源芒草的研究进展与综合利用现状,并展望了今后的发展前景。     

Variation in the calorific value and total energy content of the lesser sandeel (Ammodytes marinus) and other fish preyed on by seabirds

Wet and dry calorific values (energy densities) and total energy content of lesser sandeel Ammodytes marinus , sprat Sprattus sprattus , Atlantic herring Clupea harengus , whiting Merlangius merlangus , saithe Pollachius virens and cod Gadus morhua , were measured. Calorific values varied both within and between species. Larger fish tended to have higher calorific values than small ones, particularly when considered in terms of wet weight, but there was considerable temporal variation. The calorific values and body weights of sandeels larger than 10 cm showed marked seasonal trends and in consequence the total energy content of a sandeel of given length in summer is approximately double the spring value. The calorific values of herring and sprat also varied from month to month but seasonal cycles were less obvious. Whiting varied least. Both calorific values and total energy content of individual sprat were very variable in summer (the spawning season of this species). Because there is so much intraspecific variation, care must be taken when assessing the relative merits (in terms of energy) of different species as prey. The practical difficulties of obtaining reliable data on wet calorific values are discussed and the use of dry calorific values and dry weight/length relationships is recommended.     

Seasonal changes in calorific value of three pacific coast seaweeds,and their significance to some marine invertebrate herbivores

Samples of three intertidal seaweeds, Iridaea cordata (Turner) Bory, Hedophyllum sessile (C. Agardh) Setchell and Lessoniopsis littoralis (Farlow and Setchell) Reinke, collected at nine intervals over the period May 1971–May 1972, showed statistically significant seasonal fluctuations in percentage dry weight, percentage ash content, and calorific value. Percentage dry matter was generally highest in late summer through winter, whereas ash content was low. All three species showed a distinct annual cycle in calorific value of live (damp-dried) material, being highest during August–February for Hedophyllum and Iridaea, and during August–December for Lessoniopsis. Calorific values of dry material similarly varied seasonally for all species, but the differences were not significant for Iridaea. On an ash-free basis, the calorific values of Hedophyllum and Iridaea were variable during the year and only Lessoniopsis showed significantly higher values in late summer and autumn.The seasonal variability in calorific value of seaweeds has important implications in the feeding ecology of certain invertebrate herbivores. For example, while the chiton, Katherina tunicata Wood, consumed less Hedophyllum in the autumn than during the spring and summer, caloric intake did not decrease proportionately due to an inverse cycle in calorific value of Hedophyllum.In addition, we discuss for a number of invertebrate herbivores their feeding preferences, and the importance of calorific value of seaweeds and other factors which may have been involved in the evolution of these preferences.     

Specific leaf mass, fresh: dry weight ratio, sugar and protein contents in species of Lamiaceae from different light environments

Samples from eleven species of Lamiaceae were collected from different light environments in Venezuela for laboratory analysis. The studied species were: Plectranthus scutellarioides (Ps), Scutellaria purpurascens (Sp), Hyptis pectinata (Hp)), H. sinuata (Hs). Leonorus japonicus (Lj), Plecthranthus amboinicus (Pa) Ocimum hasilicum (Ocb), O. campechianum (Occ) Origanum majorana (Orm), Rosmarinus officinali, (Ro) and Salvia officinalis (So). Protein and soluble sugar contents per unit of area were measured, Specific Leaf Mass (SLM) and fresh:dry weight (FW/DW) ratios were calculated. The higher values for soluble sugars contents were present in sun species: Lj, Pa, Ocb, Occ, Orm, Ro and So; the lower values were obtained in low light species: Ps, Sp, Hp, Hs. The values of protein content do not show any clear trend or difference between sun and shade environments. The lowest values for the fresh weight: dry weight ratio are observed in sun species with the exception of Lj and Pa, while the highest value is observed in Pa, a succulent plant. The higher values of specific leaf mass (SLM) (Kg DMm(-2)) are observed in sun plants. The two way ANOVA revealed that there were significant differences among species and between sun and low light environments for sugar content and FW:DW ratio. while SLM was significant for environments but no significant for species, and not significant for protein for both species and environments. The soluble sugar content, FW:DW ratio and SLM values obtained in this work, show a clear separation between sun and shade plants. The sugar content and FW:DW ratio are distinctive within the species, and the light environment affected sugar content. FW:DW ratio and SLM. These species may he shade-tolerant and able to survive in sunny environments. Perhaps these species originated in shaded environments and have been adapting to sunny habitats.     

植物热值的测定

植物热值是草原生态系统中能流研究的重要指标,热值测定采用氧弹法,其原理是将定量试样在充氧的弹筒中燃烧,由燃烧后水温的升高计算试样发热量,为了获得准确测定结果,应注意读温准确、试样均匀、选择最佳氧气压力,以及尽量减少对样品的污染。测定结果表明,草原植物的热值随不同植物种,以及同一种植物不同部位和生长发育的阶段而变化。     

植物热值的测定

植物热值是草原生态系统中能流研究的重要指标。热值测定采用氧弹法,其原理是将定量试样在充氧的弹筒中燃烧,由燃烧后水温的升高计算试样发热量。为了获得准确测定结果,应注意读温准确、试样均匀、选择最佳氧气压力,以及尽量减少对样品的污染。测定结果表明,草原植物的热值随不同植物种,以及同一种植物不同部位和生长发育的阶段而变化。     

Growth,water and nutrient status of plants in relation to patterns of variations in concentrations of dry matter and nutrient elements in base-to-top leaves

Summary Patterns of variations in dry matter concentrations in tomato plants reflected production and translocation of dry matter, implying the possibility of controlling and regulating growth and development of plants by use of dry matter concentration as a useful parameter.Dry matter concentrations, analogous to nutrient concentrations, varied depending on growth conditions, and on type, age and position of plant organs.Interpretation of patterns of variations in contents and concentrations of leaf dry matter in plants, grown under widely different conditions, agreed with the source/sink hypothesis.High water applications were associated with high dry matter concentrations in upper leaves of young pot plants with low sink capacity and with low dry matter concentrations in leaves of older, trough-grown plants with high sink capacity.Accumulation of dry matter in upper leaves of plants is suggested to be associated with development of secondary sinks and, accumulation of dry matter in lateral shoots is considered as a possible explanation of apical dominance.Water regime and transpiration influenced distribution of contents of dry and fresh matter and of absorbed nutrient elements. Redistribution was influenced by water regime.The term, distribution is in the following used in connection with not only absolute values (contents) but also relative values (concentrations).     

Reproductive efficiency and growth of Emex australis in relation to stress

The reaction of Emex australis to different degrees of stress was examined in a pot experiment by varying pot size and in a field experiment by varying density. In pots, the proportion of energy in seeds was more stable to the imposition of stress than in roots and stems; that in roots increasing with increasing stress and that in stems declining. Similarly in the field, there was little difference between densities of 1–32 plants m^?2 in the proportion of seeds in biomass. There were no significant differences in mean individual seed weights in either experiment and all plants set seed. Again in both experiments, high stress plants were more precocious than low stress ones. In pots, this took the form of earlier attainment of maxima in calorific values, ‘reproductive effort’, root, stem and seed weights and in the field, a shorter life cycle and earlier senescence. In pots, estimates of the overall mean reproductive effort were 62% for the low and medium stress plants and 36% for the high stress plants. The results are discussed in terms of the high values for reproductive effort, the plasticity and precocity of E. australis under stress and the implications for weed control.     

福州鼓山季风常绿阔叶林及其林缘几种植物叶热值和营养成分

研究了福州鼓山次生的南亚热带季风常绿阔叶要及其林缘不同层次１３种植物叶热值、灰分含是及营养成分。结果表明：群落的不同层次平均灰分含量从低到高依次是乔木层（６．８％）,草本层（８．５％）、灌木层（１０％）;平均含灰分热值（ＧＣＶ）从低到高低次是草本层（１６．８９ＫＪ／ｇ）、灌木层（１７．７５ＫＪ／ｇ）、乔木层（１９．７９ＫＪ／ｇ）;平均不含灰分热值（ＡＦＣＶ）从低到高依次是草本层（１８．５５ＫＪ／ｇ     

Endophytic fungi (Neotyphodium coenophialum) affect the growth and mineral uptake, transport and efficiency ratios in tall fescue (Festuca arundinacea)

Neotyphodium coenophialuminteracts mutualistically with its host grasses. Tall fescue (Festuca arundinacea Schreb.) plants infected by the fungal endophyte,Neotyphodium coenophialum(Morgan-Jones and Gams) Glenn, Bacon and Hanlin, often perform better than non-infected plants, especially in limited resource environments. However, there is a scarcity of information about endophyte-grass ecotypes interaction in Andisols of temperate regions. Clones of three tall fescue ecotypes (Fukaura, Koiwai and Showa) either infected with N. coenophialum (E+) or noninfected (E–) were grown in Andisols (Black Andisol: naturally low content of phosphorus, high in other nutrients; Red Andisol: naturally high content of phosphorus, low in other nutrients) for 133 days in a controlled environment. Cumulative shoot dry weight, daily regrowth rates (tiller number, plant height and shoot dry matter) after clippings and nutrient uptake, transport and efficiency ratios were measured. In Black Andisol, E+ plants had significantly higher cumulative shoot dry weight as well as daily regrowth rates than E– plants, while in Red Andisol the reverse was true. Among the ecotypes studied, Showa had the highest shoot growth. Significantly higher phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) uptake as well as transport were identified in E+ vs. E– plants grown in Black Andisol. With few exceptions, values for nutrient efficiency ratios were not significantly different between E+ and E– plants grown in both soils. Significant three-way interaction (endophyte × ecotype × soil) for cumulative shoot dry weight and regrowth rate revealed that the ecotype specific regrowth responses to endophyte infection were depended on soil nutrient conditions. Vegetative growth and nutrient acquisition in tall fescue varied with ecotype and were modified by abiotic (soil fertility status) as well as biotic (endophyte infection) factors.     

Copper tolerance of the biomass crops Elephant grass (Pennisetum purpureum Schumach), Vetiver grass (Vetiveria zizanioides) and the upland reed (Phragmites australis) in soil culture

Pot trials were conducted to study the influence of copper (Cu) on the growth and biomass of Elephant grass (EG, Pennisetum purpureum Schumach), Vetiver grass (VG, Vetiveria zizanioides) and the upland reed (UR, Phragmites australis). Cu toxicity in EG, VG and UR was positively correlated with the total and bioavailable Cu concentrations in the soil. Based on the EC₅₀, dry weights, Cu contents, chlorophyll contents and photosynthesis rates, the Cu tolerance of the three species followed the trend EG > VG > UR. There were no significant differences in the unit calorific values among the different plants, though the total calorific values of EG were higher than those of VG and UR due to its higher biomass. The addition of KH₂PO₄ to the soil decreased the bioavailability of Cu and the Cu uptake by plants. EG could therefore be a good candidate for growth on Cu-contaminated soils, especially those improved by phosphate.     

Carbonisation of oil palm trunks at moderate temperatures

Thousands of tonnes of dry oil palm trunks will be produced annually in Malaysia after about 1990. A project was initiated to study the feasibility of converting palm trunks into charcoal. Carbonisation was done at terminal temperatures of 400–550°C with holding times of 1–3 h and at two heating rates. From laboratory-scale pyrolysis studies, it was found that holding time does not affect the quantity and quality of the charcoal produced, while heating rate has a minor influence. However, as terminal temperature increases, both yield and volatile content decrease while the fixed carbon content increases. The calorific value and ash contents are independent of the parameters studied and their respective values are 4032 kcal/kg and 37.2%. Since the calorific value is low and the ash content high, it is concluded that oil palm trunks are not suitable for the production of charcoal fuel.     

Analyse pondérale, élémentaire et calorimétrique des stades juvéniles de Copépodes pélagiques au cours d'une année

The change in dry weight over a year for the five copepodid states of Centropages typicus and Temora stylifera is given. The amounts of carbon and nitrogen, expressed as percentages of dry weight, are higher for copepodids than for adults. The values of the $\text{C}\text{N}$ ratios may be regarded as constant for the different stages and of the same order as those of the adults. The calorific values of young stages are higher than those of adults, because of the relatively high carbon content. A good correlation was found between the caloric value per animal (or per unit dry weight) and the dry weight of individuals.It seems that the ecological efficiency in terms of energy transport will be greater when the copepod populations are younger.     

Variations in the energy content of freshwater fish

The calorific value of the three-spined stickleback, Gasterosteus aculeatus , varied with its size, sex and the season. Fish of 16 mg dry weight had a value of 1950 cal/g while for fish of 313 mg the value was 470 cal/g. The califoric value of gravid females was 23% above that of males of comparable size. The califoric value of a tropical cichlid, Tilapia nilotica , with a dry weight of 11 g was 4300 cal/g, the calorific values of the tissues ranged from 2500 cal/g for bone to 5190 cal/g for muscle.     

TECHNICAL NOTE: THE PREPARATION OF MOLLUSCAN TISSUE FOR PRODUCTION ESTIMATES

Oven-drying at 60°C under vacuum, and presumably also dryingat higher temperatures, leads to relatively high losses of volatile,highly-calorific components, with a resultant underestimateof dry weight, lipid content and calorific content. Freeze-dryingis to be generally recommended. Fresh material should be usedwherever possible for the estimation of tissue parameters. Freezingor formalin-fixation may be used for estimations of wet weights,but only freezing if dry weights or calorific contents are alsorequired. (Received 26 November 1981;     

Isotopic values of plants in relation to water availability in the Eastern Mediterranean region

Plant C and N isotope values often correlate with rainfall on global and regional scales. This study examines the relationship between plant isotopic values and rainfall in the Eastern Mediterranean region. The results indicate significant correlations between both C and N isotope values and rainfall in C₃ plant communities. This significant relationship is maintained when plant communities are divided by plant life forms. Furthermore, a seasonal increase in C isotope values is observed during the dry season while N isotope values remain stable across the wet and dry seasons. Finally, the isotopic pattern in plants originating from desert environments differs from those from Mediterranean environments because some desert plants obtain most of their water from secondary sources, namely water channeled by local topographic features rather than direct rainfall. From these results it can be concluded that water availability is the primary factor controlling C and N isotope variability in plant communities in the Eastern Mediterranean.     

Altitudinal variation in total lipid and soluble sugar content in herbaceous plants on Mount Olympus (Greece)

Lipid and soluble sugar concentrations of leaves and stems of 168 herbaceous species, growing along an altitudinal gradient of Mount Olympus are presented. It was shown that the concentration of total lipids increased with increasing altitude, while the content of total soluble sugars decreased. The line fitting data concerning lipid and soluble sugar calorific values runs parallel to that fitting data concerning calorific content of ash free dry weight.     

Yolk energy utilization in Macrobrachium nobilii (Henderson & Mathai)

Energy content of Macrobrachium nobilii (Henderson & Mathai) is 0.19 cal in a freshly laid egg, 0.14 cal in a freshly hatched zoea, and 0.09 cal in an 8-day-old non-feeding zoea. These values indicate that the yolk is utilized with an efficiency of 74%, and that yolk equivalent to 0.1 cal is provided in an egg to meet embryonic and larval metabolism. The high yolk utilization efficiency and the high calorific content of the freshly hatched zoeae (5753 cal/g dry wt) are considered as adaptations to larval migration.     

Vegetative growth and photosynthesis in coffee plants under different watering and fertilization managements in Yunnan,SW China

In a field experiment Coffea arabica L. was subjected to various moisture and fertilizer regimes in Simao, Yunan, SW China. The experimental treatments consisted of eight factorial combinations of two fertilization levels (high and low) and four watering treatments applied in the dry season: application of dry rice straw mulch, drip irrigation, mulching plus drip irrigation on the soil surface, and control (no mulching or irrigation). The growth of the coffee plants was monitored throughout the course of a full year. Two clear growth peaks were detected (one at the beginning and one in the middle of the wet season) in plants subjected to all treatments, and the growth rhythm of coffee plants was not regulated by extrinsic abiotic factors. High fertilization resulted in a significantly higher relative growth rates for both height and length of the branches during the growth peaks than the low fertilization treatment. In the dry season, increasing the soil moisture contents by irrigation and/or mulching enhanced the plants’ gas exchange, but the soil water status had no significant effects on the internal fluorescence parameters of photosystem 2. More fertilized plants had a greater ability to acclimate to high-irradiance environments than the lightly fertilized plants, showing significant lower diurnal photoinhibition, associated with higher energy utilization through photochemistry and energy dissipation through the xanthophyll cycle. Hence the wet season is the optimum period for photosynthetic carbon fixation and vegetative growth of coffee plants. Higher than routinely applied levels of fertilization are required to optimize the coffee plants’ photosynthetic acclimation and growth in the studied environment. Both soil moisture conserving practices tested, mulching and drip irrigation, had significant effects on the growth and photosynthesis of the coffee plants, but the former was more practical than the latter.     

Water sources and water-use efficiency in mediterranean coastal dune vegetation

In coastal environments plants have to cope with various water sources: rainwater, water table, seawater, and mixtures. These are usually characterized by different isotopic signatures ( (18)O/ (16)O and D/H ratios). Xylem water reflects the isotopic compositions of the water sources. Additionally, water-use efficiency (WUE) can be assessed with carbon isotope discrimination (Delta) analyses. Gas exchange, Delta of leaf dry matter, and isotopic composition (delta (18)O) of xylem water were measured from June to August 2001 in herbaceous perennials of mobile dunes (Ammophila littoralis, Elymus farctus) and sclerophyllous shrubs and climbers (Arbutus unedo, Pistacia lentiscus, Phillyrea angustifolia, Qercus ilex, Juniperus oxycedrus, Smilax aspera) of consolidated dunes. Assimilation rates were rather low and did not show clear seasonal patterns, possibly due to limited precipitation and generally low values of stomatal conductance. The lowest values were shown in S. aspera. Different physiological patterns were found, on the basis of delta (18)O and Delta analyses. Values of delta (18)O of xylem water of phanerophytes were remarkably constant and matched those of the water table, indicating dependence on a reliable water source; values of Delta were relatively high, indicating low intrinsic WUE, with the exception of J. oxycedrus. Surprisingly, very high delta (18)O values were found for the xylem water from S. aspera in August. This suggests retrodiffusion of leaf water to xylem sap in the stem or direct uptake of water by leaves or stems, owing to dew or fog occurrence. Low Delta values indicated high WUE in S. aspera. Contrasting strategies were shown by the species of mobile dunes: E. farctus relied on superficial water and exhibited low WUE, accordingly to its therophyte-like vegetative cycle; on the contrary, A. littoralis used deeper water sources, showing higher WUE in relation to its long-lasting vegetative habit.