Seasonal pattern of leaf production and its effects on assimilation in giant summer-green herbs in deciduous forests in northern Japan

2006 ◽  
Vol 84 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Tomokazu Tani ◽  
Gaku Kudo
Keyword(s):  
Dark Respiration ◽  
Seasonal Pattern ◽  
Light Availability ◽  
High Irradiance ◽  
Tree Canopy ◽  
Deciduous Forests ◽  
Carbon Gain ◽  
Canopy Closure ◽  
Leaf Production ◽  
Short Period

Understory vegetation of northern deciduous forests in far eastern Asia is characterized by giant summer-green herbs. We examined the patterns of height growth, leaf accumulation, photosynthetic characteristics, daily net assimilation, and dry matter allocation within aboveground parts of six giant summer-green herbs with reference to light conditions in deciduous forests. Plant height, leaf number, and total leaf area per plant increased with progressing tree-canopy closure in five species ( Cacalia hastata L. subsp. orientalis Kitam., Cirsium kamtschaticum Ledeb., Filipendula kamtschatica (Pall.) Maxim. f. kamtschatica, Senecio cannabifolius Less., and Urtica platyphylla Wedd.) that had continuous leaf production throughout the growing season, whereas one species ( Veratrum album L. subsp. oxysepalum Hulten) with early leaf production, completed leaf production mostly before the beginning of tree-canopy closure. Maximum photosynthetic and dark respiration rates decreased seasonally in all species. Species with continuous leaf emergence accumulated leaves acclimatized to shade conditions, which offset the decreasing photosynthesis of individual leaves with progressing tree-canopy closure, resulting in stable carbon gain even under decreasing light availability. In contrast, V. album assimilated vigorously during the short period of high irradiance before tree-canopy closure, and decreased its assimilation rate continuously thereafter.

On the Role of Photosynthetic Responses in Constraining the Habitat Distribution of Rainforest Plants

1988 ◽  
Vol 15 (2) ◽  
pp. 343 ◽  
Author(s):  
CB Field
Keyword(s):  
Dark Respiration ◽  
Complex Function ◽  
Light Availability ◽  
Leaf Nitrogen ◽  
Photosynthetic Characteristics ◽  
Light Environment ◽  
Total Carbon ◽  
Carbon Gain ◽  
Canopy Architecture ◽  
Nitrogen Levels

Two rainforest species that differ in the range of light environments encountered by an individual provide a model system for illustrating implications of diurnal variation and spatial heterogeneity of the light environment within single canopies. The two species are similar in the acclimation of leaf-level photosynthetic characteristics to the leaf's past light environment, but are distinguished by the limited ability of the high-light species to decrease dark respiration in response to growth under shade. Over 24 h, total carbon gain from a leaf increases with increasing light, but may increase or decrease with increasing nitrogen. Intermediate nitrogen levels and photosynthetic capacities yield maximum daily carbon gain in only a narrow range of light environments. The ratio of daily photosynthesis to leaf nitrogen is a complex function of nitrogen, photosynthetic characteristics, and light availability in a microsite. Nitrogen levels in real leaves may be close to the optima, but leaf nitrogen levels are clumped relative to the optima. Daily carbon gain from a canopy of fixed total nitrogen tends to increase as the leaf area of the canopy decreases, a trend caused by two factors. First, photosynthetic capacity is a nearly linear function of leaf nitrogen up to the highest nitrogen levels observed in nature. Second, only leaves with nitrogen levels above a substantial threshold are competent to generate positive rates of net photosynthesis. Differences between the species in canopy architecture and leaf duration have counteracting effects on long-term nitrogen-use efficiency.

Effects of canopy light gap and early emergence on the growth and reproduction of Geranium maculatum

1987 ◽  
Vol 65 (2) ◽  
pp. 242-245 ◽  
Author(s):  
Theresa Schutte Dahlem ◽  
Ralph E. J. Boerner
Keyword(s):  
Genetic Recombination ◽  
Early Spring ◽  
Leaf Expansion ◽  
Carbon Gain ◽  
Canopy Closure ◽  
Gap Formation ◽  
Early Emergence ◽  
Short Period ◽  
Fruit Abortion ◽  
Light Gap

Biomass and reproduction of Geranium maculatum L. were measured in an artificial canopy light gap and under a closed canopy. The effects of emergence date were also compared. Increased light in the canopy gap resulted in increased biomass, rhizome mass, and percent of plants flowering in the second growing season after gap formation. The importance of proximate carbon in reducing fruit abortion was determined experimentally. The rate of fruit abortion increased and the number of days required for leaf expansion decreased when the plants were shaded by neutral screens. The reproductive effort of G. maculatum is thus primarily controlled by the previous year's carbon gain, while the proportion of flowers that matured to seeds was a function of proximate carbon gain. Shoots of G. maculatum emerged over a period of approximately 6 weeks in early spring, with canopy closure occurring midway through this interval. Early emergence of plants under the intact canopy permitted exploitation of the increased light levels in the period prior to canopy closure. This led to slightly increased aboveground growth and rhizome storage and a significant increase in the time spent in leaf expansion, though no differences in reproductive output existed between early and later emerging plants. Early emergence was less advantageous for gap plants. The role of gap-phase growth in G. maculatum is in increased genetic recombination and dispersal during this short period when the balance of sexual versus asexual reproduction is altered.

Survey of filamentous populations in nutrient removal plants in four European countries

1998 ◽  
Vol 37 (4-5) ◽  
pp. 281-289 ◽  
Author(s):  
Dick H. Eikelboom ◽  
Andreas Andreadakis ◽  
Kjaer Andreasen
Keyword(s):  
Nutrient Removal ◽  
Seasonal Pattern ◽  
Plug Flow ◽  
Phosphate Removal ◽  
Particulate Fraction ◽  
Biological Nutrient Removal ◽  
Process Conditions ◽  
Minor Importance ◽  
Filamentous Microorganisms ◽  
Short Period

A joint EU research project aimed at solving activated sludge bulking in nutrient removal plants was initiated in 1993. The project started with a survey of the size and composition of the filamentous population in nutrient removal plants in Denmark, Germany, Greece and the Netherlands. The results show that biological nutrient removal process conditions indeed favour filamentous microorganisms in their competition with floc forming organisms. An increase in the size of the filamentous population resulted in a deterioration of the settling properties of the biomass, except for plants with Bio-P removal conditions. It is assumed that in the latter case the dense clusters of Bio-P bacteria increase the weight of the flocs, and compensate for the effect of the larger number of filaments. Although exceptions frequently occur, the following sequence in decreasing filamentous organism population size was observed for the process conditions indicated: - completely mixed + simultaneous denitrification; - completely mixed + intermittent aeration/denitrification; - alternating anoxic/oxic process conditions, with an anaerobic tank for biological phosphate removal (Bio-Denipho); - alternating anoxic/oxic process conditions (Bio-Denitro); - predenitrification The surveys provided little information about the effect of nutrient removal in plants with plug flow aeration basins. Simultaneous precipitation with aluminium salts nearly always resulted in a low number of filaments and a good settling sludge. The size of the filamentous organism population showed a seasonal pattern with a maximum in winter/early spring and a minimum during summer (in Greece: during autumn). This seasonal variation is primarily caused by the effect of the season on the population sizes of M. parvicella, N. limicola and Type 0092. M. parvicella is by far the most important filamentous species in nutrient removal plants. In Denmark only, Type 0041 also frequently dominates the filamentous population, but seldom causes severe bulking. Considering their frequency of occurrence, approx. 10 other filamentous micro-organisms are of minor importance. Growth of some of these species, viz. those which use soluble substrate, can be prevented by the introduction of Bio-P process conditions. M. parvicella and Type 0041 (and probably also Actinomycetes and the Types 1851 and 0092) seem to compete for the same substrates i.e. the influent particulate fraction. Most of the differences in composition of the filamentous microorganism population can be explained by whether or not premixing of influent and recycled sludge is used. In general, premixing for a short period of time followed by anoxic conditions favours Type 0041. M. parvicella seems to proliferate if the particulate fraction is first hydrolysed or if it enters the plant via an oxic zone. It is concluded that bulking in nutrient removal plants is mainly caused by filamentous species requiring the particulate fraction for their growth.

Influence of physiological phenology on the seasonal pattern of ecosystem respiration in deciduous forests

2014 ◽  
Vol 21 (1) ◽  
pp. 363-376 ◽  
Author(s):  
Mirco Migliavacca ◽  
Markus Reichstein ◽  
Andrew D. Richardson ◽  
Miguel D. Mahecha ◽  
Edoardo Cremonese ◽  
...  
Keyword(s):  
Ecosystem Respiration ◽  
Seasonal Pattern ◽  
Deciduous Forests

scholarly journals Competition for Light Affects Alfalfa Biomass Production More Than Its Nutritive Value in an Olive-Based Alley-Cropping System

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 233
Author(s):  
Alberto Mantino ◽  
Cristiano Tozzini ◽  
Enrico Bonari ◽  
Marcello Mele ◽  
Giorgio Ragaglini
Keyword(s):  
Biomass Production ◽  
Nutritive Value ◽  
Alley Cropping ◽  
Light Availability ◽  
Agroforestry Systems ◽  
Tree Canopy ◽  
Soil Protection ◽  
Olive Orchard ◽  
Competition For Light ◽  
Perennial Legumes

Cropping among trees with perennial legumes is one option for increasing agro-ecosystem services, such as improving the nitrogen supply and increasing soil protection by herbaceous vegetation. Moreover, cropping under the canopy of olive trees should diversify the farm production, compared to the traditional fallow management. Among perennial legumes, alfalfa (Medicago sativa L.) produces abundant biomass under Mediterranean rainfed condition. Based on this, a two-year field experiment was implemented in southern Tuscany in a rainfed olive orchard to test the competition for light effects on alfalfa biomass production and nutritive value. Light availability under the tree canopy was measured by hemispherical photos. In both years, the alfalfa yield of under-canopy varied according to the tree presence. A significant relationship between biomass production and light availability was recorded. The nutritive value of under-canopy alfalfa was similar to that of the open-grown alfalfa. However, same significant differences did however occur, between shaded and sole crop. When differences were found, under-canopy herbage was characterised by a higher content of crude protein and a lower content of fibre with respect to open-grown. In a hilly silvoarable olive orchard, alfalfa biomass accumulation was reduced mainly due to scarce light availability, therefore tree management such as pruning and plantation layout can enhance the herbage productivity. Studying shade tolerant forage legumes in order to enhance the yield and nutritive value of herbage production in rainfed agroforestry systems is essential.

scholarly journals Phenology as a strategy for carbon optimality: a global model

2014 ◽  
Vol 11 (3) ◽  
pp. 763-778 ◽  
Author(s):  
S. Caldararu ◽  
D. W. Purves ◽  
P. I. Palmer
Keyword(s):  
Leaf Growth ◽  
Mechanistic Model ◽  
Leaf Age ◽  
Light Availability ◽  
Carbon Assimilation ◽  
Carbon Gain ◽  
Area Index ◽  
Growing Season Length ◽  
Tropical Areas ◽  
Gains And Losses

Abstract. Phenology is essential to our understanding of biogeochemical cycles and the climate system. We develop a global mechanistic model of leaf phenology based on the hypothesis that phenology is a strategy for optimal carbon gain at the canopy level so that trees adjust leaf gains and losses in response to environmental factors such as light, temperature and soil moisture, to achieve maximum carbon assimilation. We fit this model to five years of satellite observations of leaf area index (LAI) using a Bayesian fitting algorithm. We show that our model is able to reproduce phenological patterns for all vegetation types and use it to explore variations in growing season length and the climate factors that limit leaf growth for different biomes. Phenology in wet tropical areas is limited by leaf age physiological constraints while at higher latitude leaf seasonality is limited by low temperature and light availability. Leaf growth in grassland regions is limited by water availability but often in combination with other factors. This model will advance the current understanding of phenology for ecosystem carbon models and our ability to predict future phenological behaviour.

Photosynthesis and physiological traits of evergreen broadleafed saplings during winter under different light environments in a temperate forest

2006 ◽  
Vol 84 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Yoshiyuki Miyazawa ◽  
Kihachiro Kikuzawa
Keyword(s):  
Temperate Forest ◽  
Light Availability ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Leaf Mass Per Area ◽  
Camellia Japonica ◽  
Leaf Mass ◽  
Unit Leaf ◽  
Canopy Trees ◽  
Photosynthetic Traits

Photosynthetic traits of the evergreen broadleafed species Camellia japonica L. and Quercus glauca Thunb. were continuously investigated during autumn and winter using saplings that grew in different light environments (gap, deciduous canopy understory, and evergreen canopy understory) in a temperate forest. Light-saturated rates of net photosynthesis in midwinter and spring were lower than those in autumn. Photosynthetic capacity, scaled to a common leaf temperature of 25 °C, increased or remained stable after autumn and then decreased in spring in most leaves. Photosynthetic traits per unit leaf area were different among leaves in different light environments of both Camellia and Quercus during most periods. However, photosynthetic traits per unit leaf mass did not differ among leaves in different light environments, suggesting that differences in photosynthetic traits were mainly due to different leaf mass per area among leaves. Photosynthetic rates under light availability typical in the environment were lower in winter than in autumn in leaves in the sun in a gap but were not different in leaves in the shade under evergreen canopy trees. Thus, the importance of winter carbon gain for annual carbon gain is small in leaves in a gap but is large in leaves under evergreen canopy trees.

The photosynthetic response of American chestnut seedlings to differing light conditions

2007 ◽  
Vol 37 (9) ◽  
pp. 1714-1722 ◽  
Author(s):  
Heather M. Joesting ◽  
Brian C. McCarthy ◽  
Kim J. Brown
Keyword(s):  
Deciduous Forest ◽  
Photosynthetic Capacity ◽  
Dark Respiration ◽  
Nitrogen Concentration ◽  
American Chestnut ◽  
Control Treatment ◽  
Carbon Gain ◽  
Leaf Mass Per Area ◽  
Light Conditions ◽  
Eastern Deciduous Forest

Restoration attempts to reintroduce American chestnut trees to the eastern deciduous forest by means of a disease-resistant Chinese–American hybrid seed are in progress. Knowing the light conditions required for optimum seedling performance is necessary to maximize the success of reintroduction. American chestnut ( Castanea dentata (Marsh.) Borkh.) seedlings were planted in two replicate forests in Vinton County, Ohio, in areas that had been thinned (more available light) and in control areas (intact canopy, less available light). The photosynthetic capacity of 12 seedlings per treatment was assessed using an infrared gas-exchange analyzer. Seedlings in the thinned treatment reached light-saturating rates of photosynthesis at an irradiance level approximately 33% higher than did the seedlings in the control treatment. Seedlings grown in the thinned treatment had a significantly greater maximum rate of photosynthesis (Amax), dark respiration rate (Rd), and daily carbon gain per seedling than seedlings grown in the control treatment. The light compensation point (LCP), quantum efficiency (ϕ), leaf mass per area (LMA), and leaf nitrogen concentration per unit leaf area (Narea) were not significantly different between treatments. American chestnut seedlings in the thinned treatment clearly maximize leaf-level photosynthetic capacity. These results will aid land managers in planning reintroduction trials by providing information on the light conditions required for maximum seedling success.

scholarly journals High light alongside elevated PCO2 alleviates thermal depression of photosynthesis in a hard coral (Pocillopora acuta)

2020 ◽  
Vol 223 (20) ◽  
pp. jeb223198
Author(s):  
Robert A. B. Mason ◽  
Christopher B. Wall ◽  
Ross Cunning ◽  
Sophie Dove ◽  
Ruth D. Gates
Keyword(s):  
Elevated Temperature ◽  
Ocean Acidification ◽  
Environmental Changes ◽  
Dark Respiration ◽  
Interactive Effect ◽  
Light Availability ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Photochemical Quenching ◽  
Strong Light

ABSTRACTThe absorbtion of human-emitted CO2 by the oceans (elevated PCO2) is projected to alter the physiological performance of coral reef organisms by perturbing seawater chemistry (i.e. ocean acidification). Simultaneously, greenhouse gas emissions are driving ocean warming and changes in irradiance (through turbidity and cloud cover), which have the potential to influence the effects of ocean acidification on coral reefs. Here, we explored whether physiological impacts of elevated PCO2 on a coral–algal symbiosis (Pocillopora acuta–Symbiodiniaceae) are mediated by light and/or temperature levels. In a 39 day experiment, elevated PCO2 (962 versus 431 µatm PCO2) had an interactive effect with midday light availability (400 versus 800 µmol photons m−2 s−1) and temperature (25 versus 29°C) on areal gross and net photosynthesis, for which a decline at 29°C was ameliorated under simultaneous high-PCO2 and high-light conditions. Light-enhanced dark respiration increased under elevated PCO2 and/or elevated temperature. Symbiont to host cell ratio and chlorophyll a per symbiont increased at elevated temperature, whilst symbiont areal density decreased. The ability of moderately strong light in the presence of elevated PCO2 to alleviate the temperature-induced decrease in photosynthesis suggests that higher substrate availability facilitates a greater ability for photochemical quenching, partially offsetting the impacts of high temperature on the photosynthetic apparatus. Future environmental changes that result in moderate increases in light levels could therefore assist the P. acuta holobiont to cope with the ‘one–two punch’ of rising temperatures in the presence of an acidifying ocean.

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