Statistical evaluation of data on leaf growth and phyllochron as derived from leaf length measurements

1991 ◽  
Vol 33 (3) ◽  
pp. 181-191 ◽  
Author(s):  
K. Zvara ◽  
L. Natr
Keyword(s):  
Statistical Evaluation ◽  
Leaf Growth ◽  
Leaf Length ◽  
Length Measurements ◽  
Evaluation Of Data

scholarly journals An Evaluation of Leaf Biomass : Length Ratio as a Tool for Nondestructive Assessment in Eelgrass (Zostera marinaL.)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Hector Echavarria-Heras ◽  
Elena Solana-Arellano ◽  
Kun-Seop Lee ◽  
Shinya Hosokawa ◽  
Ernesto Franco-Vizcaíno
Keyword(s):  
Allometric Scaling ◽  
Leaf Growth ◽  
Threshold Value ◽  
Leaf Length ◽  
Length Ratio ◽  
Leaf Biomass ◽  
Data Sets ◽  
Length Measurements ◽  
Using Data

The characterization of biomass and its dynamics provides valuable information for the assessment of natural and transplanted eelgrass populations. The need for simple, nondestructive assessments has led to the use of the leaf biomass-to-length ratio for converting leaf-length measurements, which can be easily obtained, to leaf growth rates through the plastochrone method. Using data on leaf biomass and length collected in three natural eelgrass populations and a mesocosm, we evaluated the suitability of a leaf weight-to-length ratio for nondestructive assessments. For the data sets considered, the isometric scaling that sustains the weight-to-length proxy always produced inconsistent fittings, and for leaf-lengths greater than a threshold value, the conversion of leaf length to biomass generated biased estimations. In contrast, an allometric scaling of leaf biomass and length was highly consistent in all the cases considered. And these nondestructive assessments generated reliable levels of reproducibility in leaf biomass for all the ranges of variability in leaf lengths. We argue that the use of allometric scaling for the representation of leaf biomass in terms of length provides a more reliable approach for estimating eelgrass biomass.

scholarly journals Effects of leaf length and development stage on the triple oxygen isotope signature of grass leaf water and phytoliths: insights for a proxy of continental atmospheric humidity

2019 ◽  
Vol 16 (23) ◽  
pp. 4613-4625 ◽  
Author(s):  
Anne Alexandre ◽  
Elizabeth Webb ◽  
Amaelle Landais ◽  
Clément Piel ◽  
Sébastien Devidal ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Climate Model ◽  
Isotope Composition ◽  
Leaf Growth ◽  
Development Stage ◽  
Mean Value ◽  
Leaf Length ◽  
Leaf Water ◽  
Grass Species ◽  
Leaf Biomass

Abstract. Continental relative humidity (RH) is a key climate parameter, but there is a lack of quantitative RH proxies suitable for climate model–data comparisons. Recently, a combination of climate chamber and natural transect calibrations have laid the groundwork for examining the robustness of the triple oxygen isotope composition (δ′18O and 17O-excess) of phytoliths, that can preserve in sediments, as a new proxy for past changes in RH. However, it was recommended that besides RH, additional factors that may impact δ′18O and 17O-excess of plant water and phytoliths be examined. Here, the effects of grass leaf length, leaf development stage and day–night alternations are addressed from growth chamber experiments. The triple oxygen isotope compositions of leaf water and phytoliths of the grass species F. arundinacea are analysed. Evolution of the leaf water δ′18O and 17O-excess along the leaf length can be modelled using a string-of-lakes approach to which an unevaporated–evaporated mixing equation must be added. We show that for phytoliths to record this evolution, a kinetic fractionation between leaf water and silica, increasing from the base to the apex, must be assumed. Despite the isotope heterogeneity of leaf water along the leaf length, the bulk leaf phytolith δ′18O and 17O-excess values can be estimated from the Craig and Gordon model and a mean leaf water–phytolith fractionation exponent (λPhyto-LW) of 0.521. In addition to not being leaf length dependent, δ′18O and 17O-excess of grass phytoliths are expected to be impacted only very slightly by the stem vs. leaf biomass ratio. Our experiment additionally shows that because a lot of silica polymerises in grasses when the leaf reaches senescence (58 % of leaf phytoliths in mass), RH prevailing during the start of senescence should be considered in addition to RH prevailing during leaf growth when interpreting the 17O-excess of grass bulk phytoliths. Although under the study conditions 17O-excessPhyto do not vary significantly from constant day to day–night conditions, additional monitoring at low RH conditions should be done before drawing any generalisable conclusions. Overall, this study strengthens the reliability of the 17O-excess of phytoliths to be used as a proxy of RH. If future studies show that the mean value of 0.521 used for the grass leaf water–phytolith fractionation exponent λPhyto-LW is not climate dependent, then grassland leaf water 17O-excess obtained from grassland phytolith 17O-excess would inform on isotope signals of several soil–plant-atmosphere processes.

Area Measurement of Mesquite (Prosopis glandulosa) Leaves by Using Leaf- Length Measurements

1967 ◽  
Vol 128 (1) ◽  
pp. 22-24 ◽  
Author(s):  
C. W. Wendt ◽  
R. H. Haas ◽  
J. R. Runkles
Keyword(s):  
Leaf Length ◽  
Area Measurement ◽  
Prosopis Glandulosa ◽  
Length Measurements

scholarly journals Review on Construction Procedures of Driving Cycles

2020 ◽  
Vol 5 (2) ◽  
pp. 266-285
Author(s):  
Levente Czégé ◽  
Attila Vámosi ◽  
Imre Kocsis
Keyword(s):  
Energy Consumption ◽  
Data Collection ◽  
Dynamic Simulation ◽  
Statistical Evaluation ◽  
Driving Cycle ◽  
Driving Cycles ◽  
Construction Techniques ◽  
The Future ◽  
Evaluation Of Data

The goal of this paper is to give an overview of the literature of construction techniques of driving cycles. Our motivation for the overview is the future goal of constructing our own driving cycles for various types of vehicles and routes. This activity is part of a larger project focusing on determination of fuel and energy consumption by dynamic simulation of vehicles. Accordingly, the papers dealing with sample route determination, data collection and processing, driving cycle construction procedures, statistical evaluation of data are in our focus.

scholarly journals Effects of temperatures on growth, physiological, and antioxidant characteristics in Houttuynia cordata

2021 ◽  
Vol 49 (4) ◽  
pp. 12536
Author(s):  
Yu-Syuan LI ◽  
Kuan-Hung LIN ◽  
Chun-Wei WU ◽  
Yu-Sen CHANG
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Leaf Growth ◽  
Antioxidant Properties ◽  
Leaf Length ◽  
Leafy Vegetables ◽  
Photosynthetic Parameters ◽  
Health Food ◽  
Higher Plant ◽  
Houttuynia Cordata

Houttuynia cordata Thunb. (HC) is a traditional medicinal plant with a variety of pharmaceutical activities. The objective of this study was to investigate the growth, photosynthetic parameters, and antioxidant properties of HC plants in response to various temperatures. Pots of HC plants were maintained in day/night temperatures of 15/10 °C, 20/15 °C, 25/20 °C (control), 30/25 °C, and 35/30 °C for two months in each of five growth chambers having a 13.5 h photoperiod at 396, 432, 474, 449, and 619 µmol·m-2·s-1 radiation, respectively. Eight plants for each temperature were randomly placed in a growth chamber. HC plants survived at 30/25 °C and 35/30 °C treatments and had significantly higher plant heights, leaf numbers, and soil-plant analysis development (SPAD) and normalized difference vegetation index (NDVI) values compared to other treatments. However, long-term 35/30 °C treatment caused reductions in leaf length and width, significantly decreasing shoot and leaf fresh weight (FW) and dry weight (DW) compared to 30/25 °C treatment and controls. These results indicate that HC leaf development was affected during the 35/30 °C treatment, and that both SPAD and NDVI can help in advancing our understanding of the photosynthesis process in HC. Moreover, all plants subjected to 15/10 °C suffered more severely in all traits and parameters than other treatments. Therefore, HC plants tended to be heat-tolerant and exhibited adaptive morphologic plasticity to 30/25 °C conditions. Positive and significant correlations were observed among temperatures and total phenolics (TP), total flavonoids (TF), chlorogenic acid (CGA), and hyperoside (HO) content, and all bioactive contents increased as temperature increased, except that both CGA and HO content were remarkably decreased after 30/25 °C treatment. Thus, 30/25 °C treatment would be more beneficial for high marketability resulting from increased leaf number, DW, and all secondary metabolites compared to other treatments, and for use as a health food and for medicinal purposes. In addition, leaf growth, physiological parameters, and secondary metabolite accumulations in HC plants can be optimized for commercial production via temperature control technologies. This approach may also be applicable to leafy vegetables to produce stable industrial supplies having high leaf yields and metabolite content.

Reduced cellular cross-sectional area in the leaf elongation zone of wheat causes a decrease in dry weight deposition under saline conditions

2001 ◽  
Vol 28 (2) ◽  
pp. 165 ◽  
Author(s):  
Yuncai Hu ◽  
Urs Schmidhalter
Keyword(s):  
Spatial Distribution ◽  
Leaf Growth ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Leaf Length ◽  
Cross Sectional Area ◽  
Elongation Zone ◽  
Sectional Area ◽  
Leaf Base ◽  
Cross Sectional

Expansion and dry weight (DW) of wheat leaves are spatially distributed along the axis and affected by salinity. The objective of this study was to evaluate the effect of salinity on the spatial distribution of cellular cross-sectional area and DW in the elongating and mature leaf zones of leaf 4 of the main stem of spring wheat (Triticum aestivum L. cv. Lona) during its linear growth phase. Plants were grown in illitic–chloritic silt loam with 0 and 120 mM NaCl in a growth chamber. Cellular cross-sectional area and DW contents of leaves were determined on the 5–20-mm scale along the leaf axis. Spatial distribution of cellular cross-sectional area changed slightly with distance within the elongation zone in both treatments. The cellular cross-sectional area of the leaf at 120 mM NaCl was reduced by 32% at 5 mm, as compared with about 36% averaged from the region between 5 and 30 mm from the leaf base, indicating that the reduction in the cellular cross-sectional area by salinity occurred mainly at the leaf base when the leaf initiates. A slight decrease in the DW per leaf length at a given location in the elongation zone may be due to the strongly decreased cellular cross-sectional area by salinity. This suggests that the limitation of leaf growth by salinity may be due mainly to the effect of salinity on leaf expansion, but not due to the effect on the synthesis of dry matter.

Stem and leaf growth of alpine sun and prairie shade ecotypes of Stellaria longipes under different photoperiods: role of ethylene

2006 ◽  
Vol 84 (9) ◽  
pp. 1496-1502 ◽  
Author(s):  
Linda J. Walton ◽  
Leonid V. Kurepin ◽  
David M. Reid ◽  
C.C. Chinnappa
Keyword(s):  
Leaf Growth ◽  
Stem Elongation ◽  
Leaf Length ◽  
Leaf Expansion ◽  
Alpine Plants ◽  
Growth Responses ◽  
Stellaria Longipes ◽  
Length And Area ◽  
Radiation Conditions

Plant ecotypes of Stellaria longipes Goldie from competitive, shade-adapted prairie habitat and less competitive, nonshaded alpine habitat were subjected to shortened or extended photoperiod conditions. Increasing daylength was positively correlated to increased stem elongation in both ecotypes. Leaf length and area for shade (prairie) plants was significantly altered with increased photoperiods, whereas sun (alpine) plants exhibited minimal leaf expansion in response to increased photoperiod. Increased ethylene evolution in the alpine genotype during rapid stem elongation and extended photoperiods suggests that ethylene plays a growth regulatory role in this sun-adapted genotype. The prairie genotype evolved less ethylene during these same periods, indicating either a diminished requirement for elevated ethylene to effect elongation and leaf expansion responses or possibly increased ethylene sensitivity because of interactions with other hormones, such as gibberellin or auxin. The sun genotype consistently produced more ethylene than the shade genotype under all photoperiod treatments. We conclude that photoperiod alters stem elongation and leaf expansion responses; similar trends were observed for extended photoperiods as were observed for shaded conditions, specifically low light intensity (photosynthetically active radiation) conditions. Further, ethylene levels altered during these responses, especially in sun-adapted alpine plants, which suggests that ethylene is involved in these growth responses.

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