scholarly journals A Bayesian model for xylem vessel length accommodates subsampling and reveals skewed distributions in species that dominate seasonal habitats.

2016 ◽  
Vol 3 ◽  
pp. e003 ◽  
Author(s):  
Brad Oberle ◽  
Kiona Ogle ◽  
Juan Carlos Penagos Zuluaga ◽  
Jonathan Sweeney ◽  
Amy E. Zanne
Keyword(s):  
Water Stress ◽  
Sampling Error ◽  
Secondary Growth ◽  
Length Distribution ◽  
Vascular Anatomy ◽  
Woody Species ◽  
Bayesian Framework ◽  
Species Variation ◽  
Length Variation ◽  
Vessel Length

Vessel  length  is  an  important  but  understudied  dimension  of  variation  in  angiosperm  vascular  anatomy. Among other traits, vessel length mediates an important tradeoff between hydraulic efficiency and safety that could  influence  how  plants  respond  to  extreme  weather  with  climate  change.  However,  the  functional significance  of vessel length variation within individual stems is poorly known, in part because existing data analysis methods handle uncertainty in a way that makes vessel length distributions difficult to compare. We provide a solution to this problem through a hierarchical Bayesian framework for estimating vessel lengths and we demonstrate the flexibility of this method by applying it to data from serial cross sections of dye injected stems. Our approach can accelerate data collection and accommodate  associated uncertainties by statistically correcting for bias and error that result from subsampling images. We illustrate our analytical framework by estimating and comparing vessel length distributions for 21 woody species characteristic of a North American forest.  The best-fit  model  corrected  for both bias due to secondary  growth  and sampling  error  within  and among  species.  Vessel  length  estimates  from  this  model  varied  by  almost  an  order  of  magnitude  and parameters  of these  distributions  correlated  with  point  estimates  derived  from  a different,  commonly  used method. Furthermore, we show how key contrasts can be estimated with the Bayesian framework, and in doing so, we show that the shape of the vessel length distribution differed between ring- and diffuse-porous species, suggesting that within-stem vessel length variation corresponds to water stress seasonality and contributes to landscape-level  habitat segregation. Our analysis method revealed the importance of within-stem variation in vessel length, and our results complement work on between-species variation in average vessel length, further illuminating how vascular anatomy can influence woody plants’ responses to water stress.

scholarly journals Vessel-Length Distribution in Branches, Stem and Roots of Acer Rubrum L.

IAWA Journal ◽  
1982 ◽  
Vol 3 (2) ◽  
pp. 103-109 ◽  
Author(s):  
Martin H. Zimmermann ◽  
Daniel Potter
Keyword(s):  
Length Distribution ◽  
Acer Rubrum ◽  
Vessel Length

scholarly journals Full- and Half-Gilbert Tessellations with Rectangular Cells

2013 ◽  
Vol 45 (1) ◽  
pp. 1-19 ◽  
Author(s):  
James Burridge ◽  
Richard Cowan ◽  
Isaac Ma
Keyword(s):  
Set Theory ◽  
Poisson Point Process ◽  
Sampling Error ◽  
Length Distribution ◽  
Poisson Processes ◽  
Full Model ◽  
Second Moments ◽  
Stopping Set ◽  
Seed Points ◽  
North And South

We investigate the ray-length distributions for two different rectangular versions of Gilbert's tessellation (see Gilbert (1967)). In the full rectangular version, lines extend either horizontally (east- and west-growing rays) or vertically (north- and south-growing rays) from seed points which form a Poisson point process, each ray stopping when another ray is met. In the half rectangular version, east- and south-growing rays do not interact with west and north rays. For the half rectangular tessellation, we compute analytically, via recursion, a series expansion for the ray-length distribution, whilst, for the full rectangular version, we develop an accurate simulation technique, based in part on the stopping-set theory for Poisson processes (see Zuyev (1999)), to accomplish the same. We demonstrate the remarkable fact that plots of the two distributions appear to be identical when the intensity of seeds in the half model is twice that in the full model. In this paper we explore this coincidence, mindful of the fact that, for one model, our results are from a simulation (with inherent sampling error). We go on to develop further analytic theory for the half-Gilbert model using stopping-set ideas once again, with some novel features. Using our theory, we obtain exact expressions for the first and second moments of the ray length in the half-Gilbert model. For all practical purposes, these results can be applied to the full-Gilbert model—as much better approximations than those provided by Mackisack and Miles (1996).

scholarly journals A semi-automated method for measuring xylem vessel length distribution

2020 ◽  
Vol 32 (4) ◽  
pp. 331-340
Author(s):  
Luciano Pereira ◽  
Marcela T. Miranda ◽  
Gabriel S. Pires ◽  
Vinícius S. Pacheco ◽  
Xinyi Guan ◽  
...  
Keyword(s):  
Length Distribution ◽  
Xylem Vessel ◽  
Vessel Length ◽  
Automated Method

Anatomical and ultrastructural studies on gelatinous fibers in the organs of non-woody xerophytic and hydrophytic species

Botany ◽  
2019 ◽  
Vol 97 (10) ◽  
pp. 529-536 ◽  
Author(s):  
Tayeme Cristina Piva ◽  
Silvia Rodrigues Machado ◽  
Edna Scremin-Dias
Keyword(s):  
Secondary Growth ◽  
Woody Species ◽  
Distribution Patterns ◽  
Structural Features ◽  
Ultrastructural Studies ◽  
Gelatinous Fibers ◽  
Transmission Electron ◽  
Secondary Layer ◽  
Dry Soil ◽  
Electron Lucent

Gelatinous fibers (G-layer) occur widely in various organs and plant tissues of both primary and secondary origin, but they are best known in tension wood. Here, we describe the occurrence, distribution patterns, and structural features of G-fibers in non-woody species of xerophytes and hydrophytes in Brazilian Cerrado (dry soil) and Chaco (wet or periodically waterlogged soils). G-fibers were present in all of the studied species, but were more abundant and more developed in xerophytes. They were associated with the phloem of leaves and primary stems and with the xylem of three xerophytic species that exhibited incipient secondary growth. The G-layer was non-lignified and characterized by greater thickness, lower density, and loose appearance in relation to the secondary layers. Under a transmission electron microscope, G-fibers displayed two secondary parietal layers (S1 and S2) in Prosopis rubriflora Hassle. (xerophyte), three secondary layers (S1, S2, and S3) in Eriosema campestre Benth. var. campestre (xerophyte), and a single secondary layer (S1) in Ludwigia leptocarpa Nutt. (hydrophyte). In P. rubriflora, mature G-fibers exhibited a loose-appearing electron-lucent region (transition zone) between G- and S-layers (secondary layers). In addition to mechanical support, this study suggests the involvement of G-fibers in water storage.

Vessel-length distribution in stems of some American woody plants

1981 ◽  
Vol 59 (10) ◽  
pp. 1882-1892 ◽  
Author(s):  
Martin H. Zimmermann ◽  
Ayodeji A. Jeje
Keyword(s):  
Woody Plants ◽  
Large Diameter ◽  
Length Distribution ◽  
Vitis Labrusca ◽  
Vessel Length ◽  
Particle Penetration ◽  
Air Volume ◽  
Desk Calculator ◽  
Flow Through ◽  
Diffuse Porous

Vessel-length distributions in some trees, shrubs, and a vine have been calculated from measurements of particle penetration and of air-volume flow through the xylem. In shrubs and diffuse-porous species, longest vessels were about 1 m long, but most of them were much shorter, the largest percentage in the 0–10 cm length class. In the two ring-porous species investigated (Quercus rubra and Fraxinus americana), the longest vessels often were as long as the tree's stem, but most of them were much shorter. In the grapevine (Vitis labrusca) which has large-diameter vessels (ca. 300 μm) a small percentage of the vessels was 8 m, but most of them were less than 5 m long. In a given species, lengths of the longest vessel were quite variable, but the distribution of the short lengths was more constant. In general, vessel lengths are correlated with vessel diameters: wide vessels are longer. Even in diffuse-porous species, the slightly narrower latewood vessels are somewhat shorter than the wider early wood vessels. The method is a simplified version of that described by Skene and Balodis, but using a programmable desk calculator. It works best with diffuse-porous species in which vessels are randomly distributed in the stem, and less well in species with wide vessels, because as vessels reach the length of the stem itself, they cannot be randomly distributed.

scholarly journals Growth and Physiological Responses of Sugarcane to Drought Stress at an Early Growth Stage

2020 ◽  
Vol 2 (4) ◽  
pp. 451-460
Author(s):  
Bui The Khuynh ◽  
Vu Ngoc Thang ◽  
Vu Dinh Chinh ◽  
Pham Thi Thom
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Leaf Area ◽  
Early Stage ◽  
Photosynthetic Pigment ◽  
Genotypic Differences ◽  
Length Variation ◽  
Fresh Weight ◽  
Effects Of Drought ◽  
Response To Water

A pot experiment was conducted in a net house to evaluate the effects of drought stress (a 20-day water withholding treatment from 100-120 days after planting) on the growth and physiology of five sugarcane cultivars. The results showed that water stress at an early stage significantly affected sugarcane growth and physiology. Water stress resulted in reductions in plant height, stalk diameter, and leaf number of sugarcane, in addition to reductions in the photosynthetic pigment content, Fv/Fm, and SPAD (Soil Plant Analysis Development) readings after the 20-day withholding water period (120 DAP), and in stem, root, and leaf fresh weights, and leaf area at 150 DAP. Besides, drought stress led to increases in stomata density and decreases in stomata length. Variation was also found among the cultivars in response to water stress. Significant genotypic differences in stem fresh weight and leaf area under water stress among the cultivars were observed. The highest value of stem fresh weight under stressed conditions was recorded in ROC22 (50.6 g), followed by QĐ159 (46.5g), ROC16 (46.2g), ROC10 (46.1g), and VL06 (44.4g). However, the highest DTI was recorded in ROC16, followed by VL06, ROC10, QĐ93-159, and ROC22, respectively.

Theory of vessel-length determination: the problem of nonrandom vessel ends

1993 ◽  
Vol 71 (2) ◽  
pp. 297-302 ◽  
Author(s):  
Melvin T. Tyree
Keyword(s):  
Theoretical Analysis ◽  
Key Words ◽  
Length Distribution ◽  
The Other ◽  
Double Difference ◽  
Correct Result ◽  
Correction Algorithm ◽  
Negative Numbers ◽  
Vessel Length ◽  
Length Determination

A theoretical analysis was undertaken to examine the accuracy of algorithms commonly used to compute vessel lengths from paint perfusion experiments. The double-difference (DD) algorithm assumes that all vessels have randomly distributed vessel ends along the axis of the paint-perfused stem and that vessels do not branch. When these conditions were met, the DD algorithm overestimated the frequency of short vessels and underestimated the frequency of long vessels. When these conditions were not met, negative numbers for frequencies were outputted by the DD algorithm. Two algorithms for correcting for negative numbers were examined, one used by Zimmermann and the other used by Ewers and Fisher. Neither algorithm produced the correct result, but the correction algorithm proposed by Ewers and Fisher produced more accurate results. Key words: vessel-length distribution.

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