Stomatal conductance patterns of Equisetum giganteum stems in response to environmental factors in South America

Botany ◽  
2014 ◽  
Vol 92 (10) ◽  
pp. 701-712 ◽  
Author(s):  
Chad E. Husby ◽  
José Delatorre-Herrera ◽  
Steven F. Oberbauer ◽  
Alfredo Grau ◽  
Lázaro Novara
Keyword(s):  
Stomatal Conductance ◽  
South America ◽  
Vapor Pressure Deficit ◽  
Red Light ◽  
Atacama Desert ◽  
Diurnal Pattern ◽  
Passive System ◽  
Unusual Structure ◽  
Physiological Adaptations ◽  
Stomatal Apparatus

As the most basal monilophytes, eusporangiate ferns can provide key insights into the origins of plant physiological adaptations. The genus Equisetum, the most morphologically and physiologically unusual genus of eusporangiate ferns, has a stomatal apparatus that is unique among all plants. Patterns of stomatal diffusive conductance (gw) were measured in the giant horsetail, Equisetum giganteum L. in southern South America. Maximum gw values (<200 mmol·m−2·s−1) were low in comparison with typical angiosperm leaves, but were in the range measured in other pteridophytes. The range of measured gw was similar in contrasting environments of the Atacama Desert and northwestern Argentina. Stems in shade had a significantly lower gw than those in light. Developing stems had a higher average gw than mature stems. Stomatal conductance was higher for upper stem internodes than for middle internodes. Late-morning gw was primarily related to stem diameter, stem surface temperature, and interactions among these factors and vapor pressure deficit (VPD), light, elevation, and groundwater salinity. Equisetum giganteum likely has a passive system of stomatal regulation depending on overall stem turgor and red light. The stomatal conductance of patterns of this species exhibited a diurnal pattern typical of other pteridophytes, despite its unusual structure.

Effect of Mycorrhizal Fungi on Gas Exchange of Micropropagated Guava Plantlets (Psidium guajava L.) during Acclimatization and Plant Establishment

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 501c-501
Author(s):  
Andrés A. Estrada-Luna ◽  
Jonathan N. Egilla ◽  
Fred T. Davies
Keyword(s):  
Tissue Culture ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vapor Pressure ◽  
Mycorrhizal Fungi ◽  
Vapor Pressure Deficit ◽  
Psidium Guajava ◽  
Glomus Etunicatum ◽  
Plant Establishment ◽  
Use Efficiency

The effect of mycorrhizal fungi on gas exchange of micropropagated guava plantlets (Psidium guajava L.) during acclimatization and plant establishment was determined. Guava plantlets (Psidium guajava L. cv. `Media China') were asexually propagated through tissue culture and acclimatized in a glasshouse for eighteen weeks. Half of the plantlets were inoculated with ZAC-19, which is a mixed isolate containing Glomus etunicatum and an unknown Glomus spp. Plantlets were fertilized with modified Long Ashton nutrient solution containing 11 (g P/ml. Gas exchange measurements included photosynthetic rate (A), stomatal conductance (gs), internal CO2 concentration (Ci), transpiration rate (E), water use efficiency (WUE), and vapor pressure deficit (VPD). Measurements were taken at 2, 4, 8 and 18 weeks after inoculation using a LI-6200 portable photosynthesis system (LI-COR Inc. Lincoln, Neb., USA). Two weeks after inoculation, noninoculated plantlets had greater A compared to mycorrhizal plantlets. However, 4 and 8 weeks after inoculation, mycorrhizal plantlets had greater A, gs, Ci and WUE. At the end of the experiment gas exchange was comparable between noninoculated and mycorrhizal plantlets.

scholarly journals Improving the LPJmL4-SPITFIRE vegetation-fire model for South America using satellite data

2019 ◽  
Author(s):  
Markus Drüke ◽  
Matthias Forkel ◽  
Werner von Bloh ◽  
Boris Sakschewski ◽  
Manoel Cardoso ◽  
...  
Keyword(s):  
South America ◽  
Ecosystem Functioning ◽  
Vapor Pressure Deficit ◽  
Water Vapor Pressure ◽  
Fire Danger ◽  
Above Ground Biomass ◽  
Model Data ◽  
Burnt Area ◽  
Water Vapor Pressure Deficit ◽  
Global Vegetation

Abstract. Vegetation fires influence global vegetation distribution, ecosystem functioning, and global carbon cycling. Specifically in South America, changes in fire occurrence together with land use change accelerate ecosystem fragmentation and increase the vulnerability of tropical forests and savannas to climate change. Dynamic Global Vegetation Models (DGVMs) are valuable tools to estimate the effects of fire on ecosystem functioning and carbon cycling under future climate changes. However, fire-enabled DGVMs have partly poor performances in capturing the magnitude, spatial patterns, and temporal dynamics of burnt area as observed by satellites. As fire is controlled by the interplay of weather conditions, vegetation properties and human activities, fire modules in DGVMs can be improved in various aspects. As a starting point, we here focus on improving the controls of climate and hence fuel moisture content on fire danger in the LPJmL4-SPITFIRE DGVM in South America and especially for the Brazilian fire-prone biomes Caatinga and Cerrado. We therefore test two alternative model formulations (standard Nesterov index and a newly implemented water vapor pressure deficit) for climate effects on fire danger within a formal model-data integration setup where we estimate model parameters against satellite data sets of burnt area (GFED4) and above ground biomass of trees. Our results show that the optimized model improves the representation of spatial patterns and the seasonal to inter-annual dynamics of burnt area especially in the Cerrado/Caatinga region. In addition, the model improves the simulation of above-ground biomass and plant functional types (PFTs). We obtained the best results by using the water vapor pressure deficit (VPD) for the calculation of fire danger. The VPD includes, in comparison to the Nesterov index, a representation of the air humidity and the vegetation density. This work shows the successful application of a systematic model-data integration setup, as well as the integration of a new fire danger formulation, in order to optimize a process-based fire-enabled DGVM. It further highlights the potential of this approach to achieve a new level of accuracy in comprehensive global fire modelling and prediction.

scholarly journals Growth and Acclimation of In Vitro-Propagated M9 Apple Rootstock Plantlets under Various Visible Light Spectrums

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1017
Author(s):  
Guem-Jae Chung ◽  
Jin-Hui Lee ◽  
Myung-Min Oh
Keyword(s):  
Stomatal Conductance ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Light Quality ◽  
Red Light ◽  
High Ratio ◽  
The Other ◽  
Ex Vitro ◽  
Apple Rootstock

This study aimed to explore the suitable light quality condition for ex vitro acclimation of M9 apple plantlets. Light quality treatments were set as followed; monochromatic LEDs (red (R), green (G), blue (B)) and polychromatic LEDs (R:B = 7:3, 8:2 and 9:1; R:G:B = 6:1:3, 7:1:2 and 8:1:1). Plant height of R, R9B1, and R8G1B1 treatments were significantly higher than the other treatments. The number of leaves and SPAD value of B were significantly higher than the other treatments. Root fresh weights of R9B1 and R7G1B2 treatments showed an increase of at least 1.7-times compared to R, G and R8B2. R8G1B1 accumulated higher starch contents than the other treatments. Photosynthetic rate of R9B1 and R8B2 were significantly higher than the other treatments. In terms of stomatal conductance and transpiration rate, treatments with high blue ratio such as B, R7B3 had higher values. Rubisco concentration was high in R and B among monochromatic treatments. In conclusion, red light was effective to increase photosynthetic rate and biomass and blue light increased chlorophyll content and stomatal conductance. Therefore, for R9B1 and R8G1B1, a mixture of high ratio of red light with a little blue light would be proper for the acclimation of in vitro-propagated apple rootstock M9 plantlets to an ex vitro environment.

scholarly journals Diurnal pattern of stomatal conductance in the large-leaved temperate liana Aristolochia macrophylla depends on spatial position within the leaf lamina

2013 ◽  
Vol 111 (5) ◽  
pp. 905-915 ◽  
Author(s):  
Tatiana Miranda ◽  
Martin Ebner ◽  
Christopher Traiser ◽  
Anita Roth-Nebelsick
Keyword(s):  
Stomatal Conductance ◽  
Spatial Position ◽  
Diurnal Pattern ◽  
Leaf Lamina

Response of Stomatal Conductance to Vapor Pressure Deficit in Leaves of Four Trees at the Campus of Shandong University

2014 ◽  
Vol 522-524 ◽  
pp. 1055-1058
Author(s):  
Jing Li ◽  
Xiao Guang Wang ◽  
Gui Zhai Zhang ◽  
Xue Wei Hou ◽  
Xiao Ming Li
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Response Pattern ◽  
Populus Deltoides ◽  
Shandong Province ◽  
Populus Euramericana ◽  
Parabolic Curve

Response of gas exchange to VPD in leaves of four trees (Prunus serrulata, Prunus lannesiana, Populus deltoides I-69 (I-69) and Populus × euramericana Neva (I-107)) at the campus of Shandong University in Jinan, Shandong Province were measured. The result showed that: the stomatal conductance increased with increasing VPD, and gs reached gs-max at intermediate VPD, and a steady decline in gs with further increases in VPD. This response pattern was fitted by a parabolic curve (gs=aD2+bD+c, D=VPD, R2>0.52). The gs-max at intermediate VPD with changing VPD showed that there was an optimal VPD (or RH) to plants. Therefore, while VPD (or RH) was higher or lower than the optimal VPD (or RH) of plant, gs would decrease. The response of gs to VPD in I-69 and I-107 were much more sensitive than P. serrulata and P. lannesiana.

scholarly journals Opportunistic survival strategy ofWelwitschia mirabilis: recent anatomical and ecophysiological studies elucidating stomatal behaviour and photosynthetic potential

Botany ◽  
2017 ◽  
Vol 95 (12) ◽  
pp. 1109-1123 ◽  
Author(s):  
G.H.J. Krüger ◽  
A. Jordaan ◽  
L.R. Tiedt ◽  
R.J. Strasser ◽  
M. Kilbourn Louw ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Conservation ◽  
Root Hairs ◽  
Leaf Tissue ◽  
Severe Drought ◽  
Survival Strategy ◽  
Potted Plants ◽  
New Findings ◽  
Stomatal Apparatus ◽  
Photosynthetic Potential

We present new findings on leaf and stomatal apparatus anatomy and ecophysiology of Welwitschia mirabilis Hook.f. that are relevant to survival in the desert. We show that the structure of the stomatal apparatus with thin areas in the guard cell walls is a key feature enabling an opportunistic survival strategy through reversible quick switch-over from water conservation to CO2assimilation. Desert environment and greenhouse data demonstrated that stomatal conductance increased almost immediately after dawn to reach a maximum within approximately an hour, whereupon a steep decrease occurred. After discontinuation of induced drought in potted plants, fast recovery of stomatal conductance occurred while copious new root hairs developed within 50 h. Stomatal limitation proved to be the main photosynthetic constraint under induced drought. Under severe drought stress, biochemical limitation came into play. Chlorophyll fluorescence data of in-situ plants showed that the photosynthetic potential of leaf tissue is highest near the basal meristem, but although it decreases with age, it retains activity up to the leaf apex at the end of the green part. The photosynthetic potential of potted plants was optimal at 20 °C, analogous to mesophytic plants. Our data confirms our hypothesis that leaf surface and stomatal structure play a crucial role in moisture conservation and moderating leaf temperature for desert survival.

scholarly journals Effect of Algae Treatment On Stevia Rebaudiana Growth

2018 ◽  
Vol 46 (2) ◽  
pp. 73-77
Author(s):  
Réka Czinkóczky ◽  
Áron Németh
Keyword(s):  
Blood Pressure ◽  
South America ◽  
Red Light ◽  
Stevia Rebaudiana ◽  
Reduce Blood Pressure ◽  
Steviol Glycosides ◽  
Rebaudioside A ◽  
Stevia Rebaudiana Bertoni ◽  
Biomass Yields ◽  
Set Up

Abstract Stevia rebaudiana Bertoni is a small, perennial and herbaceous shrub which originated in Paraguay (South America). Stevia rebaudiana is not native to Hungary but its cultivation and consumption may have many benefits, e.g. to reduce blood pressure and as a non-caloric sweetener. Steviol glycosides, mostly stevioside and rebaudioside A, located in the leaves are about 200–300 times sweeter than sucrose. S. rebaudina cultivation in Hungary would offer many opportunities in healthcare and the sweet industry. With the aim of achieving good green biomass yields, the effect of MACC4 autotrophic and heterotrophic algae strains was investigated by testing them as both leaf and soil fertilizers in the soil of Stevia rebaudiana seedlings and in its aqueous rooting experiments. In one of the later set up, the formation of roots was improved by combining the application of red light and algae treatment.

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