scholarly journals Bundle sheath extensions affect leaf structural and physiological plasticity in response to irradiance

2017 ◽  
Author(s):  
Maria Antonia M. Barbosa ◽  
Daniel H. Chitwood ◽  
Aristéa A. Azevedo ◽  
Wagner L. Araújo ◽  
Dimas M. Ribeiro ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Supply And Demand ◽  
Photosynthetic Performance ◽  
Bundle Sheath ◽  
Leaf Structure ◽  
Physiological Traits ◽  
Area Index ◽  
Article Type ◽  
Mesophyll Surface Area ◽  
And Function

AbstractCoordination between structural and physiological traits is key to plants’ responses to environmental fluctuations. In heterobaric leaves, bundle sheath extensions (BSEs) increase photosynthetic performance (light-saturated rates of photosynthesis, Amax) and water transport capacity (leaf hydraulic conductance, Kleaf). However, it is not clear how BSEs affect these and other leaf developmental and physiological parameters in response to environmental conditions. The obscuravenosa (obv) mutation, found in many commercial tomato varieties, leads to absence of BSEs. We examined structural and physiological traits of tomato heterobaric and homobaric (obv) near-isogenic lines (NILs) grown at two different irradiance levels. Kleaf, minor vein density and stomatal pore area index decreased with shading in heterobaric but not in homobaric leaves, which show similarly lower values in both conditions. Homobaric plants, on the other hand, showed increased Amax, leaf intercellular air spaces and mesophyll surface area exposed to intercellular airspace (Smes) in comparison with heterobaric plants when both were grown in the shade. BSEs further affected carbon isotope discrimination, a proxy for long-term water-use efficiency. BSEs confer plasticity in traits related to leaf structure and function in response to irradiance levels and might act as a hub integrating leaf structure, photosynthetic function and water supply and demand.Summary statementThe presence of bundle sheath extension (BSEs) defines leaves as heterobaric, as opposed to homobaric leaves that lack them. Multiple functions have been proposed for BSEs, but their impact on different environmental conditions is still unclear. Here, we compared a tomato (Solanum lycopersicum) homobaric mutant lacking BSEs with its corresponding heterobaric wild-type, grown under two irradiance conditions. We show that the presence of BSEs differentially alters various physiological and anatomical parameters in response to growth irradiance. We propose that BSEs could act as hubs coordinating leaf plasticity in response to environmental factors.Article typeResearch article

scholarly journals Can we predict groundwater discharge from terrestrial ecosystems using existing eco-hydrological concepts?

2011 ◽  
Vol 15 (12) ◽  
pp. 3731-3739 ◽  
Author(s):  
A. P. O'Grady ◽  
J. L. Carter ◽  
J. Bruce
Keyword(s):  
Strong Convergence ◽  
Supply And Demand ◽  
Groundwater Discharge ◽  
Terrestrial Ecosystems ◽  
Ecosystem Structure ◽  
Terrestrial Vegetation ◽  
Data Set ◽  
Area Index ◽  
Groundwater Systems ◽  
And Function

Abstract. There is increasing recognition of the role that groundwater plays in the maintenance of ecosystem structure and function. As a result, water resources planners need to develop an understanding of the water requirements for these ecosystems. In this study we reviewed estimates of groundwater discharge from terrestrial vegetation communities around Australia and explored this data set for empirical relationships that could be used to predict groundwater discharge in data poor areas. In particular we explored how leaf area index and the water balance of groundwater systems conformed to two existing ecohydrological frameworks; the Budyko framework, which describes the partitioning of rainfall into evapotranspiration and runoff within a simple supply and demand framework, and Eagleson's theory of ecological optimality. We demonstrate strong convergence with the predictions of both frameworks. Terrestrial groundwater systems discharging groundwater lie above the water limit line as defined in the Budyko framework. However, when climate wetness was recalculated to include groundwater discharge there was remarkable convergence of these sites along this water limit line. Thus, we found that there was a strong correlation between estimates of evapotranspiration derived from the Budyko's relationship with observed estimates of evapotranspiration. Similarly, the LAI of ecosystems with access to groundwater have higher LAI than those without access to groundwater, for a given climatic regime. However, again when discharge was included in the calculation of climate wetness index there was again strong convergence between the two systems, providing support for ecological optimality frameworks that maximize LAI under given water availability regimes. The simplicity and utility of these simple ecohydrological insights potentially provide a valuable tool for predicting groundwater discharge from terrestrial ecosystems, especially in data poor areas.

scholarly journals Genome-Wide Detection of SNP Markers Associated with Four Physiological Traits in Groundnut (Arachis hypogaea L.) Mini Core Collection

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 192 ◽  
Author(s):  
Abdulwahab S. Shaibu ◽  
Clay Sneller ◽  
Babu N. Motagi ◽  
Jackline Chepkoech ◽  
Mercy Chepngetich ◽  
...  
Keyword(s):  
Core Collection ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Canopy Temperature ◽  
Snp Markers ◽  
Physiological Traits ◽  
Area Index ◽  
Trait Association ◽  
Mini Core Collection ◽  
Genome Wide

In order to integrate genomics in breeding and development of drought-tolerant groundnut genotypes, identification of genomic regions/genetic markers for drought surrogate traits is essential. We used 3249 diversity array technology sequencing (DArTSeq) markers for a genetic analysis of 125 ICRISAT groundnut mini core collection evaluated in 2015 and 2017 for genome-wide marker-trait association for some physiological traits and to determine the magnitude of linkage disequilibrium (LD). Marker-trait association (MTA) analysis, probability values, and percent variation modelled by the markers were calculated using the GAPIT package via the KDCompute interface. The LD analysis showed that about 36% of loci pairs were in significant LD (p < 0.05 and r2 > 0.2) and 3.14% of the pairs were in complete LD. The MTAs studies revealed 20 significant MTAs (p < 0.001) with 11 markers. Four MTAs were identified for leaf area index, 13 for canopy temperature, one for chlorophyll content and two for normalized difference vegetation index. The markers explained 20.8% to 6.6% of the phenotypic variation observed. Most of the MTAs identified on the A subgenome were also identified on the respective homeologous chromosome on the B subgenome. This could be due to a common ancestor of the A and B genome which explains the linkage detected between markers lying on different chromosomes. The markers identified in this study can serve as useful genomic resources to initiate marker-assisted selection and trait introgression of groundnut for drought tolerance after further validation.

scholarly journals Optimizing the Remote Detection of Tropical Rainforest Structure with Airborne Lidar: Leaf Area Profile Sensitivity to Pulse Density and Spatial Sampling

2019 ◽  
Vol 11 (1) ◽  
pp. 92 ◽  
Author(s):  
Danilo Roberti Alves de Almeida ◽  
Scott C. Stark ◽  
Gang Shao ◽  
Juliana Schietti ◽  
Bruce Walker Nelson ◽  
...  
Keyword(s):  
Grain Size ◽  
Leaf Area ◽  
Laser Scanning ◽  
Forest Canopy ◽  
Primary Source ◽  
Airborne Lidar ◽  
Area Index ◽  
Pulse Density ◽  
Optimal Values ◽  
And Function

Airborne Laser Scanning (ALS) has been considered as a primary source to model the structure and function of a forest canopy through the indicators leaf area index (LAI) and vertical canopy profiles of leaf area density (LAD). However, little is known about the effects of the laser pulse density and the grain size (horizontal binning resolution) of the laser point cloud on the estimation of LAD profiles and their associated LAIs. Our objective was to determine the optimal values for reliable and stable estimates of LAD profiles from ALS data obtained over a dense tropical forest. Profiles were compared using three methods: Destructive field sampling, Portable Canopy profiling Lidar (PCL) and ALS. Stable LAD profiles from ALS, concordant with the other two analytical methods, were obtained when the grain size was less than 10 m and pulse density was high (>15 pulses m−2). Lower pulse densities also provided stable and reliable LAD profiles when using an appropriate adjustment (coefficient K). We also discuss how LAD profiles might be corrected throughout the landscape when using ALS surveys of lower density, by calibrating with LAI measurements in the field or from PCL. Appropriate choices of grain size, pulse density and K provide reliable estimates of LAD and associated tree plot demography and biomass in dense forest ecosystems.

scholarly journals SCARECROW, SCR-LIKE 23 and SHORT-ROOT control bundle sheath cell fate and function inArabidopsis thaliana

2014 ◽  
Vol 78 (2) ◽  
pp. 319-327 ◽  
Author(s):  
Hongchang Cui ◽  
Danyu Kong ◽  
Xiuwen Liu ◽  
Yueling Hao
Keyword(s):  
Cell Fate ◽  
Bundle Sheath ◽  
Sheath Cell ◽  
Short Root ◽  
Bundle Sheath Cell ◽  
And Function

Evaluation of groundnut genotypes for physiological efficiencyand high yield to suit early kharif situation

2017 ◽  
Author(s):  
A. Reshma ◽  
P. Latha ◽  
V. Umamahesh ◽  
R. P. Vasanthi ◽  
P. Sudhakar
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Crop Growth ◽  
Net Assimilation Rate ◽  
Physiological Traits ◽  
Assimilation Rate ◽  
Area Index ◽  
Crop Growth Rate ◽  
Pod Yield ◽  
Net Assimilation

Groundnut is grown during July to October in kharif season, however area under early kharif (sowing in May) is increasing in Andhra Pradsh, where ever irrigation facilities exists. Hence to identify suitable variety for the situation, fourteen pre release and two released groundnut genotypes were evaluated during early kharif 2013 for growth, physiological traits and yield attributes. At harvest genotypes TCGS-1375 (41.331 g plant-1), TCGS-1342(41.059 g plant-1) significantly recorded higher total dry matter compared to all other cultivars and checks followed by TCGS-1330 (36.667 g plant-1), TCGS-1349 (36.433 g plant-1). TCGS-1342 recorded significantly higher Crop Growth Rate (CGR) value of 33.848 g m-2 day-1, where as TCGS-1346 (0.1265 g dm-2 day-1) and TCGS-1330 (0.1262 g dm-2 day-1) recorded significantly higher Net Assimilation Rate (NAR) values at 45-60 DAS. Cultivar, TCGS-1330 recorded significantly higher pod yield 4210.44 Kg ha-1 compared to other entries and checks. The results revealed that pre release genotypes, TCGS-1342, TCGS-1375, TCGS-1330, TCGS-1346 recorded high physiological efficiency in terms of growth and physiological traits viz. total dry matter (TDM), crop growth rate (CGR), net assimilation rate (NAR) and leaf area index (LAI) and also recorded high pod yield.

scholarly journals Structure and Function of Bacterial Communities Emerging from Different Sources under Identical Conditions

2006 ◽  
Vol 72 (1) ◽  
pp. 212-220 ◽  
Author(s):  
Silke Langenheder ◽  
Eva S. Lindström ◽  
Lars J. Tranvik
Keyword(s):  
Environmental Conditions ◽  
Bacterial Communities ◽  
Fragment Length Polymorphism ◽  
Bacterial Community Composition ◽  
Rrna Gene ◽  
Polymorphism Analysis ◽  
Scale Functions ◽  
And Function ◽  
Different Sources ◽  
The 16S Rrna Gene

ABSTRACT The aim of this study was to compare two major hypotheses concerning the formation of bacterial community composition (BCC) at the local scale, i.e., whether BCC is determined by the prevailing local environmental conditions or by “metacommunity processes.” A batch culture experiment where bacteria from eight distinctly different aquatic habitats were regrown under identical conditions was performed to test to what extent similar communities develop under similar selective pressure. Differently composed communities emerged from different inoculum communities, as determined by terminal restriction fragment length polymorphism analysis of the 16S rRNA gene. There was no indication that similarity increased between communities upon growth under identical conditions compared to that for growth at the ambient sampling sites. This suggests that the history and distribution of taxa within the source communities were stronger regulating factors of BCC than the environmental conditions. Moreover, differently composed communities were different with regard to specific functions, such as enzyme activities, but maintained similar broad-scale functions, such as biomass production and respiration.

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