Rapid adjustment of leaf angle explains how the desert moss, Syntrichia caninervis, copes with multiple resource limitations during rehydration

2014 ◽  
Vol 41 (2) ◽  
pp. 168 ◽  
Author(s):  
Nan Wu ◽  
Yuan-ming Zhang ◽  
Alison Downing ◽  
Zachary T. Aanderud ◽  
Ye Tao ◽  
...  
Keyword(s):  
Light Availability ◽  
Morphological Characters ◽  
Ultrastructural Changes ◽  
Leaf Angle ◽  
Resource Limitations ◽  
Syntrichia Caninervis ◽  
Relative Water ◽  
Rapid Adjustment ◽  
Multiple Resource ◽  
Water Gain

Although the desert moss Syntrichia caninervis Mitt. is extremely desiccation tolerant, it still requires water and photosynthates for growth. The ecological significance of the leaf angle in maintaining a balance between water and light availability is critical to its survival. Active leaf repositioning balances water and light availability following rehydration. S. caninervis can adjust leaf angles from a steep (84–69°) to a stable level at 30° within 7 s after rehydration, obtaining maximum net photosynthetic gain at a shoot relative water content of ~60%. Leaf morphological characters, (leaf hair points, surface papillae and costal anatomy) and ultrastructural changes (chloroplast reordering and loss of lipid reserves as shown by changes in osmiophilic globules) were linked to rapid leaf spreading, water gain and sunlight reflectivity of leaves during rehydration. The high 377.20 ± 91.69 (cm2 g–1) surface area to mass ratio was a major factor in facilitating the rapid response to rewetting. Hyaline cells of the leaf base absorbed water, swelled and forced the leaf away from the stem as soon as rehydration commenced. Loss of leaf hair points retards leaf angle adjustment during rehydration.

scholarly journals Physiological and Genetic Bases of the Circadian Clock in Plants and Their Relationship with Herbicides Efficacy

2016 ◽  
Vol 34 (1) ◽  
pp. 191-198
Author(s):  
G. DALAZEN ◽  
A. MEROTTO JR.
Keyword(s):  
Circadian Clock ◽  
Environmental Changes ◽  
Crop Yields ◽  
Light Availability ◽  
Leaf Angle ◽  
Time Of Application ◽  
Genetic Mechanisms ◽  
Relationship Of ◽  
The Relationship

In order to adapt to daily environmental changes, especially in relation to light availability, many organisms, such as plants, developed a vital mechanism that controls time-dependent biological events: the circadian clock. The circadian clock is responsible for predicting the changes that occur in the period of approximately 24 hours, preparing the plants for the following phases of the cycle. Some of these adaptations can influence the response of weeds to the herbicide application. Thus, the objectives of this review are to describe the physiological and genetic mechanisms of the circadian clock in plants, as well as to demonstrate the relationship of this phenomenon with the effectiveness of herbicides for weed control. Relationships are described between the circadian clock and the time of application of herbicides, leaf angle and herbicide interception, as well as photosynthetic activity in response to the circadian clock and herbicide efficiency. Further, it is discussed the role of phytochrome B (phyB) in the sensitivity of plants to glyphosate herbicide. The greater understanding of the circadian clock in plants is essential to achieve greater efficiency of herbicides and hence greater control of weeds and higher crop yields.

scholarly journals Multiple resource limitations explain biomass-precipitation relationships in grasslands

2021 ◽  
Author(s):  
Siddharth Bharath ◽  
Peter B. Adler ◽  
Philip A. Fay ◽  
Eric W. Seabloom ◽  
Yann Hautier ◽  
...  
Keyword(s):  
Nutrient Availability ◽  
Nutrient Addition ◽  
Plant Performance ◽  
Resource Limitations ◽  
Herbivore Exclusion ◽  
Grassland Ecosystems ◽  
Proportional Change ◽  
Increased Sensitivity ◽  
Multiple Resource ◽  
A Site

AbstractInterannual variability in grassland primary production is strongly driven by precipitation, nutrient availability and herbivory, but there is no general consensus on the mechanisms linking these variables. If grassland biomass is limited by the single most limiting resource at a given time, then we expect that nutrient addition will not affect biomass production at arid sites. We conducted a distributed experiment manipulating nutrients and herbivores at 44 grassland sites in 8 regions around the world, spanning a broad range in aridity. We estimated the effects of 5-11 years of nutrient addition and herbivore exclusion treatments on precipitation sensitivity of biomass (proportional change in biomass relative to proportional change in rainfall among years), and the biomass in the driest year (to measure treatment effects when water was most limiting) at each site. Grazer exclusion did not interact with nutrients to influence driest year biomass or sensitivity. Nutrient addition increased driest year biomass by 74% and sensitivity by 0.12 (proportional units), and that effect did not change across the range of aridity spanned by our sites. Grazer exclusion did not interact with nutrients to influence sensitivity or driest year biomass. At almost half of our sites, the previous year's rainfall explained as much variation in biomass as current year precipitation. Overall, our distributed fertilization experiment detected co-limitation between nutrients and water governing grasslands, with biomass sensitivity to precipitation being limited by nutrient availability irrespective of site aridity and herbivory. Our findings refute the classical ideas that grassland plant performance is limited by the single most limiting resource at a site. This suggests that nutrient eutrophication will destabilize grassland ecosystems through increased sensitivity to precipitation variation.

scholarly journals Morphological characterization of 3 potential lines Cempo Ireng black rice result of Gamma-Ray irradiation

2021 ◽  
Vol 905 (1) ◽  
pp. 012024
Author(s):  
N Salsabila ◽  
Nandariyah ◽  
E Yuniastuti ◽  
B Pujiasmanto ◽  
Sutarno
Keyword(s):  
Leaf Blade ◽  
Gamma Ray ◽  
Leaf Surface ◽  
Morphological Characteristics ◽  
Morphological Characters ◽  
Morphological Characterization ◽  
Leaf Angle ◽  
Panicle Length ◽  
Black Rice ◽  
Gamma Ray Irradiation

Abstract Gamma-ray irradiation on Cempo Ireng can lead to the variation of morphological characteristics; hence, morphological characterization is necessary to determine changes in potential lines. This research aimed to characterize the potential lines as one of the requirements for proposing plant variety release and add black rice genetic diversity information. The research was carried out in the rice fields of Pakahan Village, Jogonalan, Klaten in January-June 2020 with the arrangement of potential lines 8,13 and 44 of M6 in a row. In total 30 plants were selected randomly for each potential line and observed 19 morphological characters. Data analysis was carried out descriptively and qualitatively with the Chi-Square test. The results showed that gamma-ray irradiation affects the characters of leaf angle, auricle color, ligule color, leaf-blade color, leaf surface, panicle type, grain color, apiculus color, and rice length. Potential line 8 had different characteristics compared to non-irradiated Cempo Ireng in the characters of auricle color, leaf-blade color, leaf width, panicle length, grain width, rice length, and rice width, while on potential lines 13 and 44 occur in the characters of the leaf surface and panicle length.

scholarly journals Consequences of being phenotypically mismatched with the environment: rapid muscle ultrastructural changes in cold-shocked black-capped chickadees (Poecile atricapillus)

2020 ◽  
Vol 318 (2) ◽  
pp. R274-R283 ◽  
Author(s):  
François Vézina ◽  
Emily Cornelius Ruhs ◽  
Erin S. O’Connor ◽  
Audrey Le Pogam ◽  
Lyette Régimbald ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Temperature Drop ◽  
Ultrastructural Changes ◽  
Phenotypic Traits ◽  
Phenotypic Flexibility ◽  
Pectoralis Muscle ◽  
Poecile Atricapillus ◽  
Muscle Ultrastructure ◽  
Myonuclear Domain ◽  
Rapid Adjustment

Phenotypic flexibility has received considerable attention in the last decade; however, whereas many studies have reported amplitude of variation in phenotypic traits, much less attention has focused on the rate at which traits can adjust in response to sudden changes in the environment. We investigated whole animal and muscle phenotypic changes occurring in black-capped chickadees ( Poecile atricapillus) acclimated to cold (−5°C) and warm (20°C) temperatures in the first 3 h following a 15°C temperature drop (over 3 h). Before the temperature change, cold-acclimated birds were consuming 95% more food, were carrying twice as much body fat, and had 23% larger pectoralis muscle fiber diameters than individuals kept at 20°C. In the 3 h following the temperature drop, these same birds altered their pectoralis muscle ultrastructure by increasing the number of capillaries per fiber area and the number of nuclei per millimeter of fiber by 22%, consequently leading to a 22% decrease in myonuclear domain (amount of cytoplasm serviced per nucleus), whereas no such changes were observed in the warm-acclimated birds. To our knowledge, this is the first demonstration of such a rapid adjustment in muscle fiber ultrastructure in vertebrates. These results support the hypothesis that chickadees maintaining a cold phenotype are better prepared than warm-phenotype individuals to respond to a sudden decline in temperature, such as what may be experienced in their natural wintering environment.

Ecological studies for plant characteristics of Fimbristylis miliacea under multiple resource limitations in dry-seeded upland ecosystems

2020 ◽  
pp. 1-11
Author(s):  
Tahir Hussain Awan ◽  
Sharif Ahmed ◽  
Pompe C. Sta. Cruz ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Ecological Studies ◽  
Resource Limitations ◽  
Plant Characteristics ◽  
Multiple Resource

GENETIC ANALYSIS OF QUANTITATIVE CHARACTERS IN CIGAR AND PIPE TOBACCO NICOTIANA TABACUM. I. MORPHOLOGICAL CHARACTERS

1980 ◽  
Vol 22 (2) ◽  
pp. 173-182 ◽  
Author(s):  
I. S. Ogilvie ◽  
V. Kozumplik
Keyword(s):  
Combining Ability ◽  
Diallel Cross ◽  
Morphological Characters ◽  
General Combining Ability ◽  
Leaf Length ◽  
Specific Combining Ability ◽  
Leaf Angle ◽  
Combining Abilities ◽  
Number Of Leaves ◽  
Pipe Tobacco

A diallel cross of four cigar and one pipe tobacco was analysed for the following characters: (1) height before topping (2) height after topping (3) number of leaves (4) leaf width (5) leaf length (6) leaf angle and (7) days from transplanting to flower. The experiment was performed over three years with four replications. Analysis was done for general combining ability and specific combining ability. General combining ability was in all cases greater than specific combining ability, although there were some specific combining ability effects. The line Pennbel 69 showed very high positive general combining abilities for all characters while the line Petit Havane showed negative general combining abilities for these characters. Commercial production of F1 hybrids would not seem to be of any advantage for any of these characters with these parental lines.

scholarly journals Elevated Carbon Dioxide and Chronic Warming Together Decrease Nitrogen Uptake Rate, Net Translocation, and Assimilation in Tomato

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 722
Author(s):  
Dileepa M. Jayawardena ◽  
Scott A. Heckathorn ◽  
Krishani K. Rajanayake ◽  
Jennifer K. Boldt ◽  
Dragan Isailovic
Keyword(s):  
Uptake Rate ◽  
N Uptake ◽  
Dry Mass ◽  
Leaf Angle ◽  
Resource Limitations ◽  
Total Nonstructural Carbohydrates ◽  
Whole Plant ◽  
Uptake Rates ◽  
N Assimilation ◽  
Nitrogen Uptake Rate

The response of plant N relations to the combination of elevated CO2 (eCO2) and warming are poorly understood. To study this, tomato (Solanum lycopersicum) plants were grown at 400 or 700 ppm CO2 and 33/28 or 38/33 °C (day/night), and their soil was labeled with 15NO3− or 15NH4+. Plant dry mass, root N-uptake rate, root-to-shoot net N translocation, whole-plant N assimilation, and root resource availability (%C, %N, total nonstructural carbohydrates) were measured. Relative to eCO2 or warming alone, eCO2 + warming decreased growth, NO3− and NH4+-uptake rates, root-to-shoot net N translocation, and whole-plant N assimilation. Decreased N assimilation with eCO2 + warming was driven mostly by inhibition of NO3− assimilation, and was not associated with root resource limitations or damage to N-assimilatory proteins. Previously, we showed in tomato that eCO2 + warming decreases the concentration of N-uptake and -assimilatory proteins in roots, and dramatically increases leaf angle, which decreases whole-plant light capture and, hence, photosynthesis and growth. Thus, decreases in N uptake and assimilation with eCO2 + warming in tomato are likely due to reduced plant N demand.

Repeatability of water loss and gain rates of Plethodon cinereus

2021 ◽  
pp. 1-5
Author(s):  
Geoffrey R. Smith ◽  
Abhishek V. Henry ◽  
Wesley O. Smith ◽  
Logan E. Smith
Keyword(s):  
Water Loss ◽  
Plethodon Cinereus ◽  
Colour Morph ◽  
Plethodontid Salamanders ◽  
Relative Water ◽  
Colour Morphs ◽  
Water Gain

Abstract Water loss and gain rates of amphibians are important to understanding their ecology, especially for plethodontid salamanders. We report the first estimates of repeatability of relative water loss and gain rates of the two major colour morphs of the Eastern Red-backed Salamander, Plethodon cinereus, in the fall and spring seasons. Repeatability of relative water loss in P. cinereus was >0 in the fall but not in the spring. Repeatability of relative water gain was significant for all salamanders pooled in the fall, and was not repeatable in the spring. There were no apparent differences in repeatability of relative water loss or gain between the two colour morphs. Our results suggest that the repeatability of relative water loss and gain rates varies by season, but not by colour morph.

scholarly journals Gradients of light availability and leaf traits with leaf age and canopy position in 28 Australian shrubs and trees

2006 ◽  
Vol 33 (5) ◽  
pp. 407 ◽  
Author(s):  
Ian J. Wright ◽  
Michelle R. Leishman ◽  
Cassia Read ◽  
Mark Westoby
Keyword(s):  
Optimal Allocation ◽  
Leaf Age ◽  
Light Availability ◽  
Leaf Traits ◽  
Leaf Angle ◽  
Leaf Mass Per Area ◽  
Evergreen Species ◽  
Plant Canopies ◽  
Eastern Australia ◽  
Canopy Position

Light availability generally decreases vertically downwards through plant canopies. According to optimisation theory, in order to maximise canopy photosynthesis plants should allocate leaf nitrogen per area (Narea) in parallel with vertical light gradients, and leaf mass per area (LMA) and leaf angles should decrease down through the canopy also. Many species show trends consistent with these predictions, although these are never as steep as predicted. Most studies of canopy gradients in leaf traits have concerned tall herbaceous vegetation or forest trees. But do evergreen species from open habitats also show these patterns? We quantified gradients of light availability, LMA, leaf N and phosphorus (P), and leaf angle along leaf age sequences and vertical canopy profiles, across 28 woody species from open habitats in eastern Australia. The observed trends in LMA, Narea and leaf angle largely conflicted with expectations from canopy optimisation models, whereas trends in leaf P were more consistent with optimal allocation. These discrepancies most likely relate to these species having rather open canopies with quite shallow light gradients, but also suggest that modelling the co-optimisation of resources other than nitrogen is required for understanding plant canopies.

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