Effects of Exogenous Sucrose Feeding on Photosynthesis in the C3 Plant Tobacco and the C4 Plant Flaveria bidentis

1997 ◽  
Vol 24 (3) ◽  
pp. 291 ◽  
Author(s):  
Robert T. Furbank ◽  
Jeni Pritchard ◽  
Colin L.D. Jenkins
Keyword(s):  
Gene Expression ◽  
Leaf Area ◽  
Experimental System ◽  
Threshold Level ◽  
C3 Plant ◽  
Sterile Culture ◽  
Unit Leaf ◽  
Photosynthetic Genes ◽  
Sucrose Feeding ◽  
Flaveria Bidentis

Seeds of the C4 dicot Flaveria bidentis and the C3 dicot Nicotiana tabacum were germinated on expanded cotton plugs and grown for 28–35 days in a sterile culture system with liquid nutrients supplied to the roots in the presence or absence of 5% (w/v) sucrose. Despite previous reports that supplying sucrose exogenously to plants inhibits expression of photosynthetic genes, sucrose application in this system stimulated maximum photosynthetic rates and these were comparable to those measured in glasshouse-grown material. The activities of many photosynthetic enzymes in the youngest fully expanded leaves of both Flaveria and tobacco plants were increased by sucrose feeding. Sucrose levels were increased more than 2-fold in tobacco and 3-fold in Flaveria leaves (on a leaf area basis) by sucrose application, and both hexose and starch levels also increased. Chlorophyll per unit leaf area in sucrose-fed plants increased by approximately 20% in tobacco and 2-fold in Flaveria. There was no evidence of sucrose repression of photosynthetic competence in this experimental system. We propose that, over the concentration range present in the leaves in these experiments, sucrose acts as a positive signal for photosynthetic gene expression but that, above a threshold level, inhibition of gene expression seen in other studies could still occur.

Adaptations of strangler figs to life in the rainforest canopy

2006 ◽  
Vol 33 (5) ◽  
pp. 465 ◽  
Author(s):  
Susanne Schmidt ◽  
Dieter P. Tracey
Keyword(s):  
Leaf Area ◽  
Extreme Values ◽  
Stomatal Density ◽  
Keystone Species ◽  
Nitrate Assimilation ◽  
Experimental System ◽  
Standing Tree ◽  
Free Standing ◽  
Unit Leaf ◽  
Taxonomic Groups

Figs are rainforest keystone species. Non-strangler figs establish on the forest floor; strangler figs establish epiphytically, followed by a dramatic transition from epiphyte to free-standing tree that kills its hosts. Free-standing figs display vigorous growth and resource demand suggesting that epiphytic strangler figs require special adaptations to deal with resource limitations imposed by the epiphytic environment. We studied epiphytic and free-standing strangler figs, and non-strangler figs in tropical rainforest and in cultivation, as well as strangler figs in controlled conditions. We investigated whether the transition from epiphyte to free-standing tree is characterised by morphological and physiological plasticity. Epiphyte substrate had higher levels of plant-available ammonium and phosphate, and similar levels of nitrate compared with rainforest soil, suggesting that N and P are initially not limiting resources. A relationship was found between taxonomic groups and plant N physiology; strangler figs, all members of subgenus Urostigma, had mostly low foliar nitrate assimilation rates whereas non-strangler figs, in subgenera Pharmacocycea, Sycidium, Sycomorus or Synoecia, had moderate to high rates. Nitrate is an energetically expensive N source, and low nitrate use may be an adaptation of strangler figs for conserving energy during epiphytic growth. Interestingly, significant amounts of nitrate were stored in fleshy taproot tubers of epiphytic stranglers. Supporting the concept of plasticity, leaves of epiphytic Ficus benjamina L. had lower N and C content per unit leaf area, lower stomatal density and 80% greater specific leaf area than leaves of conspecific free-standing trees. Similarly, glasshouse-grown stranglers strongly increased biomass allocation to roots under water limitation. Epiphytic and free-standing F. benjamina had similar average foliar δ13C, but epiphytes had more extreme values; this indicates that both groups of plants use the C3 pathway of CO2 fixation but that water availability is highly variable for epiphytes. We hypothesise that epiphytic figs use fleshy stem tubers to avoid water stress, and that nitrate acts as an osmotic compound in tubers. We conclude that strangler figs are a unique experimental system for studying the transition from rainforest epiphyte to tree, and the genetic and environmental triggers involved.

scholarly journals Overexpressing the HD-Zip class II transcription factor EcHB1 from Eucalyptus camaldulensis increased the leaf photosynthesis and drought tolerance of Eucalyptus

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Keisuke Sasaki ◽  
Yuuki Ida ◽  
Sakihito Kitajima ◽  
Tetsu Kawazu ◽  
Takashi Hibino ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Leaf Area ◽  
Leucine Zipper ◽  
Eucalyptus Grandis ◽  
Eucalyptus Camaldulensis ◽  
Class Ii ◽  
Cell Multiplication ◽  
Leaf Photosynthesis ◽  
Unit Leaf

Abstract Alteration in the leaf mesophyll anatomy by genetic modification is potentially a promising tool for improving the physiological functions of trees by improving leaf photosynthesis. Homeodomain leucine zipper (HD-Zip) transcription factors are candidates for anatomical alterations of leaves through modification of cell multiplication, differentiation, and expansion. Full-length cDNA encoding a Eucalyptus camaldulensis HD-Zip class II transcription factor (EcHB1) was over-expressed in vivo in the hybrid Eucalyptus GUT5 generated from Eucalyptus grandis and Eucalyptus urophylla. Overexpression of EcHB1 induced significant modification in the mesophyll anatomy of Eucalyptus with enhancements in the number of cells and chloroplasts on a leaf-area basis. The leaf-area-based photosynthesis of Eucalyptus was improved in the EcHB1-overexpression lines, which was due to both enhanced CO2 diffusion into chloroplasts and increased photosynthetic biochemical functions through increased number of chloroplasts per unit leaf area. Additionally, overexpression of EcHB1 suppressed defoliation and thus improved the growth of Eucalyptus trees under drought stress, which was a result of reduced water loss from trees due to the reduction in leaf area with no changes in stomatal morphology. These results gave us new insights into the role of the HD-Zip II gene.

Rates of Photosynthesis Relative to Activity of Photosynthetic Enzymes, Chlorophyll and Soluble Protein Content Among Ten C4 Species

1984 ◽  
Vol 11 (6) ◽  
pp. 509 ◽  
Author(s):  
H Usuda ◽  
MSB Ku ◽  
GE Edwards
Keyword(s):  
Leaf Area ◽  
Soluble Protein ◽  
High Light ◽  
Soluble Protein Content ◽  
Bisphosphate Carboxylase ◽  
Unit Leaf ◽  
C4 Species ◽  
Photosynthetic Enzymes ◽  
Rate Of Photosynthesis ◽  
High Degree

Among 10 C4 species having a wide range in photosynthetic activity, the rates of photosynthesis/leaf area under high light were examined and compared with the chlorophyll and soluble protein content and the activities of several photosynthetic enzymes. The species examined were Digitaria sanguinalis, Echinochloa crus-galli, Microstegium vimineum, Panicum capillare, Panicum miliaceum, Paspalum dilatatum, Paspalum notatum, Pennisetum purpureum, Setaria lutescens, and Zea mays. The photosynthetic rates per unit leaf area ranged from 10 to 38 �mol CO2 fixed m-2 s-1. Among the 10 species there was a high degree of correlation of rate of photosynthesis/leaf area with soluble protein (r = 0.88), ribulose 1,5-bisphosphate carboxylase (r = 0.88) and pyruvate,PI dikinase (r = 0.94), but a lower correlation of photosynthetic rate/leaf area with phosphoenolpyruvate carboxylase (r = 0.74) and no significant correlation of photosynthetic rate/leaf area with chlorophyll content (r = 0.56). Among eight species of the NADP-malic enzyme C4 subgroup, there was a good correlation of photosynthetic ratelleaf area with NADP-malate dehydrogenase (r = 0.88) and NADP- malic enzyme (r = 0.92). Extractable activities of both the ribulose 1,5-bisphosphate carboxylase and the dikinase were generally close to the rate of photosynthesis. When comparing the activity per unit leaf area of one enzyme with another, generally a high degree of correlation was found among the species. The results suggest that a given C4 species tends to maintain a balance in the activities of several photosynthetic enzymes and that there is potential to estimate capacity for C4 photosynthesis under high light through determining activity of certain photosynthetic enzymes.

scholarly journals Determining Water Use and Crop Coefficients of Five Woody Landscape Plants

2006 ◽  
Vol 24 (3) ◽  
pp. 160-165 ◽  
Author(s):  
G. Niu ◽  
D.S. Rodriguez ◽  
R. Cabrera ◽  
C. McKenney ◽  
W. Mackay
Keyword(s):  
Leaf Area ◽  
Water Use ◽  
Culture System ◽  
Growth Parameters ◽  
Growth Index ◽  
Crop Coefficient ◽  
Nerium Oleander ◽  
Culture Systems ◽  
Unit Leaf ◽  
Crop Coefficients

Abstract The water use and crop coefficient of five woody landscape species were determined by growing the shrubs both in 56-liter (15 gal) drainage lysimeters and in above-ground 10-liter containers (#3). Water use per plant, crop coefficient and overall growth parameters differed by species and culture system. Of the five species tested, Buddleia davidii ‘Burgundy’ and Nerium oleander ‘Hardy Pink’ had higher water use per plant in the lysimeters than in the containers. Water use per plant for Abelia grandiflora ‘Edward Goucher’, Euonymus japonica and Ilex vomitoria ‘Pride of Houston’ was the same for the two culture systems. Crop coefficient and growth index of A. grandiflora, E. japonica, and I. vomitoria was similar between the two systems. The growth index of B. davidii and N. oleander was much higher in the lysimeters than in the containers. Abelia grandiflora and E. japonica had more growth in the containers than in the lysimeters while I. vomitoria had slightly larger leaf area in the lysimeters than in the containers. The culture system did not affect the water use per unit leaf area of all species. Therefore, our results indicated that by quantifying the leaf area, the plant water use in the two culture systems is exchangeable.

Stomatal Development During Leaf Expansion in Tobacco and Sunflower

1975 ◽  
Vol 23 (2) ◽  
pp. 253 ◽  
Author(s):  
HM Rawson ◽  
CL Craven
Keyword(s):  
Leaf Area ◽  
Stomatal Density ◽  
Stomatal Development ◽  
Developmental Patterns ◽  
Full Size ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Wide Range ◽  
Young Leaves ◽  
Different Levels

Changes in stomatal density and size were followed in tobacco and sunflower leaves expanding from 10% of final area (10% Amax) to Amax under different levels of radiation. Lower radiation increased final leaf area, reduced stomatal densities, and increased area per stoma but had little effect on stomatal area per unit leaf area at Amax. In very young leaves (20% Amax) there was a wide range in the sizes of individual stomata, some stomata being close to full size, but by Amax differences were small. The possible relationship between the developmental patterns described and photosynthesis is briefly discussed.

Effect of Interspecific Interference, Light Intensity, and Soil Moisture on Soybean (Glycine max), Common Cocklebur (Xanthium strumarium), and Sicklepod (Cassia obtusifolia) Water Uptake

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 534-540 ◽  
Author(s):  
Ronald E. Jones ◽  
Robert H. Walker
Keyword(s):  
Soil Moisture ◽  
Light Intensity ◽  
Leaf Area ◽  
Water Uptake ◽  
Root Weight ◽  
Pressure Potential ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Shoot Weight ◽  
The Relationship

Greenhouse and growth chamber experiments with potted plants were conducted to determine the effects of interspecific root and canopy interference, light intensity, and soil moisture on water uptake and biomass of soybean, common cocklebur, and sicklepod. Canopy interference and canopy plus root interference of soybean with common cocklebur increased soybean water uptake per plant and per unit leaf area. Root interference with soybean decreased common cocklebur water uptake per plant. Canopy interference of soybean with sicklepod increased soybean water uptake per unit leaf area, while root interference decreased uptake per plant. Combined root and canopy interference with soybean decreased water uptake per plant for sicklepod. Soybean leaf area and shoot weight were reduced by root interference with both weeds. Common cocklebur and sicklepod leaf area and shoot weight were reduced by root and canopy interference with soybeans. Only common cocklebur root weight decreased when canopies interfered and roots did not. The relationship between light intensity and water uptake per unit leaf area was linear in both years with water uptake proportional to light intensity. In 1991 water uptake response to tight was greater for common cocklebur than for sicklepod. The relationship between soil moisture level and water uptake was logarithmic. Common cocklebur water uptake was two times that of soybean or sicklepod at −2 kPa of pressure potential. In 1991 common cocklebur water uptake decreased at a greater rate than soybean or sicklepod in response to pressure potential changes from −2 to −100 kPa.

Seed germination, seedling growth and habitat partitioning in two morphotypes of the tropical pioneer tree Trema micrantha in a seasonal forest in Panama

2003 ◽  
Vol 19 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Katia Silvera ◽  
John B. Skillman ◽  
J. W. Dalling
Keyword(s):  
Leaf Area ◽  
Soil Nutrient ◽  
Habitat Partitioning ◽  
Relative Growth Rates ◽  
Unit Leaf ◽  
Interspecific Differences ◽  
Pioneer Tree ◽  
Allocation Patterns ◽  
Trema Micrantha ◽  
Sun And Shade

We examined the distribution, germination, growth and photosynthetic characteristics of two co-existing morphotypes of the pioneer tree Trema micrantha at the Barro Colorado Nature Monument (BCNM), Panama. Morphotypes differed significantly in distribution and in seed characteristics. A ‘large’-seeded morphotype (endocarp mass=3.83 mg) was associated with treefall gaps in the forest interior, whereas a ‘small’-seeded morphotype (endocarp mass=1.38 mg) was found predominantly on landslides on the margins of Lake Gatun. Seeds of the small-seeded morphotype germinated faster than seeds of the large-seeded morphotype, with seedlings of the small-seeded morphotype showing both a higher Unit Leaf Rate (ULR) and a lower Specific Leaf Area (SLA). Differences in photosynthetic rates reflected differences in SLA; the small-seeded morphotype had a higher rate on a leaf area basis, while the large-seeded morphotype had a higher rate on a leaf mass basis. Although allocation patterns between morphotypes varied in a way consistent with known interspecific differences between ‘sun’ and ‘shade’ plants, relative growth rates (RGR) of the morphotypes were similar across different light conditions suggesting that factors other than light, such as water uptake efficiency, soil nutrient requirements, and perhaps seed dispersal characters may explain the habitat partitioning of morphotypes.

Carbon Isotope Discrimination and Gas Exchange in Coffea arabica During Adjustment to Different Soil Moisture Regimes

1992 ◽  
Vol 19 (2) ◽  
pp. 171 ◽  
Author(s):  
FC Meinzer ◽  
NZ Saliendra ◽  
C Crisosto
Keyword(s):  
Soil Moisture ◽  
Gas Exchange ◽  
Leaf Area ◽  
Coffea Arabica ◽  
Carbon Isotope Discrimination ◽  
Total Leaf Area ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Moisture Regimes ◽  
Area Basis

Although carbon isotope discrimination (Δ) has been reported to decline in plants growing under reduced soil moisture, there is little information available concerning the dynamics of adjustments in Δ and gas exchange following a change in soil water availability. In this study Δ, photosynthetic gas exchange, and growth were monitored in container-grown coffee (Coffea arabica L.) plants for 120 days under three soil moisture regimes. At the end of 120 d, total leaf area of plants irrigated twice weekly was one half that of plants irrigated twice daily, although their assimilation rates on a unit leaf area basis were nearly equal throughout the experiment. This suggested that maintenance of nearly constant photosynthetic characteristics on a unit leaf area basis through maintenance of a smaller total leaf area may constitute a major mode of adjustment to reduced soil moisture availability in coffee. Intrinsic water-use efficiency (WUE) predicted from foliar Δ values was highest in plants irrigated weekly, intermediate in plants irrigated twice weekly and lowest in plants irrigated twice daily. When instantaneous WUE was estimated from independent measurements of total transpiration per plant and assimilation on a unit leaf area basis, the reverse ranking was obtained. The lack of correspondence between intrinsic and instantaneous WUE was attributed to adjustments in canopy morphology and leaf size in the plants grown under reduced water supply which enhanced transpiration relative to assimilation. Values of Δ predicted from the ratio of intercellular to ambient CO2 partial pressure determined during gas exchange measurements were not always consistent with measured foliar Δ. This may have resulted from a patchy distribution of stomatal apertures in plants irrigated weekly and from a lag period between adjustment in gas exchange and subsequent alteration in Δ of expanding leaves. The importance of considering temporal and spatial scales, and previous growth and environmental histories in comparing current single leaf gas exchange behaviour with foliar Δ values is discussed.

Radiation and water balance properties of cadmium-polluted maize in a wet year

2012 ◽  
Vol 60 (3) ◽  
pp. 191-200 ◽  
Author(s):  
A. Anda
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Sensible Heat ◽  
Net Radiation ◽  
Yield Losses ◽  
Vegetative Organs ◽  
Unit Leaf ◽  
Silage Maize ◽  
Matter Production ◽  
Annual Water

The effect of spraying maize weekly with a 0.5 M concentration of Cd was studied in Hungary at two water supply levels. Cd reduced the size of the leaf area and the annual water loss. The intensity of evapotranspiration (mm water/unit leaf area) of the polluted crops grew. The higher net radiation of polluted maize resulted in an increase in sensible heat and a warmer canopy. The warmer the canopy, the higher the stress level of the contaminated crops was. While Cd caused a 28% significant decline in plant dry matter production in the rainfed plots, only a declining tendency amounting to a few percent was recorded in the ET treatment.Cd of atmospheric origin was only detected in the leaves; it was not accumulated in the grain. It was concluded from the results that the yield losses in grain maize grown on Cd-polluted areas could be mitigated by irrigation. The production of silage maize, however, is not recommended in regions affected by Cd pollution, especially in areas where irrigation is required, since supplementary water supplies promote the accumulation of Cd in the vegetative organs.

Strong restrictions on the trait range of co-occurring species in the newly created riparian zone of the Three Gorges Reservoir Area, China

2019 ◽  
Vol 12 (5) ◽  
pp. 825-833 ◽  
Author(s):  
Aiying Zhang ◽  
Will Cornwell ◽  
Zhaojia Li ◽  
Gaoming Xiong ◽  
Dayong Fan ◽  
...  
Keyword(s):  
Leaf Area ◽  
Plant Communities ◽  
Community Assembly ◽  
Three Gorges Reservoir ◽  
Riparian Zone ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Unit Leaf ◽  
Altered Hydrology ◽  
The Three Gorges

Abstract Aims Community assembly links plant traits to particular environmental conditions. Numerous studies have adopted a trait-based approach to understand both community assembly processes and changes in plant functional traits along environmental gradients. In most cases these are long-established, natural or semi-natural environments. However, increasingly human activity has created, and continues to create, a range of new environmental conditions, and understanding community assembly in these ‘novel environments’ will be increasingly important. Methods Built in 2006, the Three Gorges Dam, largest hydraulic project in China, created a new riparian area of 384 km2, with massively altered hydrology. This large, newly created ecosystem is an ideal platform for understanding community assembly in a novel environment. We sampled environment variables and plant communities within 103 plots located in both the reservoir riparian zone (RRZ) and adjacent non-flooded and semi-natural upland (Upland) at the Three Gorges Reservoir Area. We measured six traits from 168 plant species in order to calculate community-level distribution of trait values. We expected that the altered hydrology in RRZ would have a profound effect on the community assembly process for the local plants. Important Findings Consistent with previous work on community assembly, the distribution of trait values (range, variance, kurtosis and the standard deviation of the distribution neighbor distances) within all plots was significantly lower than those from random distributions, indicating that both habitat filtering and limiting similarity simultaneously shaped the distributions of traits and the assembly of plant communities. Considering the newly created RRZ relative to nearby sites, community assembly was different in two main ways. First, there was a large shift in the mean trait values. Compared to Upland communities, plant communities in the RRZ had higher mean specific leaf area (SLA), higher nitrogen per unit leaf mass (Nmass), and lower maximum height (MH). Second, in the RRZ compared to the Upland, for the percentage of individual plots whose characteristic of trait values was lower than null distributions, the reductions in the community-level range for SLA, Nmass, nitrogen per unit leaf area (Narea) and phosphorus per unit leaf area (Parea) were much larger, suggesting that the habitat filter in this newly created riparian zone was much stronger compared to longer established semi-natural upland vegetation. This stronger filter, and the restriction to a subset of plants with very similar trait values, has implications for predicting riparian ecosystems’ responses to the hydrological alterations and further understanding for human’s effect on plant diversity and plant floras.

Sign in / Sign up

Export Citation Format

Share Document