Wednesday, 28 March 2012

Transcription factor PIF4 controls the thermosensory activation of flowering

A new understanding of how plants control their timing of reproduction in response to temperature. 


Flowering time is an important trait in crops as well as affecting the life cycles of pollinator species. A molecular understanding of how temperature affects flowering will be important for mitigating the effects of climate change.

Tuesday, 21 February 2012

Functional Morphology of the Lever Mechanism of Salvia pratensis

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2735310/

Abstract

Background and Aims
The functional morphology of Salvia pratensis flowers was re-investigated, after new insights revealed that pollen dispensing is one of the main functions of the staminal lever. In particular, no detailed information was available regarding the process of pollen transfer and the forces arising between the pollen-bearing thecae and the pollinating bee's body. The assumption was made that these forces play a significant role in pollen dispensing.
 
Methods
The functional morphology of S. pratensis flowers and the interaction between flowers and bees (Apis mellifera) were studied by reconstructing stress and strains by using qualitative and semi-quantitative theoretical analysis. Flowers were manipulated to study the spatial arrangement of the filament and lever, and of the head and proboscis of the visiting bee inside the tube. Photographs and films of bee visits on flowers were used to analyse the interaction of pollinator and staminal lever.
 
Key Results
The spoon-shaped lower lever of S. pratensis has a small hole through which a bee introduces its proboscis into the corolla tube. Although mentioned for the first time by Kerner von Marilaun in 1891, presented here is the first drawing and the first photograph showing this interaction in detail. The analysis of the interaction of flower visitor and the lever mechanism revealed that the position of bees on different flowers is spatially very similar. Flower morphology constrains postures of legitimately nectar-probing bees within narrow bounds. A theoretical discussion on structural elements and force progression in the flower allows the principles of lightweight architecture in flower morphology to be recognized.
 
Conclusions
The staminal lever of S. pratensis is a pollen-dispensing device. It seems to influence the amount of pollen deposited on pollinators by determining the forces arising between the pollinator and the pollen. The relevant forces occur either during the first, dynamic phase or during the second, almost static phase of a flower visit.
Key words: Flower–pollinator interaction, bee, Apis mellifera, pollination, pollen uptake, see-saw mechanism, biomechanics, pollen dispensing
 

 


 
 

Back to the future!

Plants back to life after 30.000 years:
Scientists in Russia have grown plants from fruit stored away in permafrost by squirrels over 30,000 years ago.
The fruit was found in the banks of the Kolmya River in Siberia, a top site for people looking for mammoth bones. The Institute of Cell Biophysics team propagated plants of Silene stenophylla in vitro from the fruit tissues.

the full news on BBC News

Monday, 13 February 2012

Nectar guides & foraging


‘X’ marks the spot: The possible benefits of nectar guides to bees and plants

Functional Ecology

Volume 25, Issue 6, pages 1293–1301, December 2011

Orchid pollination: from Darwin to the present day

Abstract

In this year celebrating the bicentenary of the birth of Darwin and the sesquicentennial of the publication of Darwin's On the Origin of Species, the present paper aims to assess the impact of Darwin's legacy on the history of orchid pollination biology. To illustrate the major contribution of Darwin to this fascinating biological field, we focus on the large angraecoid orchid group and propose an overview of the complex relationships that these orchids have developed with specific pollinators. We further discuss how Darwin's seminal work on the angraecoid orchid Angraecum sesquipedale triggered the beginning of a long debate about the evolution of long floral spurs and why his idea of reciprocal evolution or ‘coevolution’ was one of the great contributions to evolutionary biology. 

Botanical Journal of the Linnean Society

Volume 161, Issue 1, pages 1–19, September 2009 

 

PLANT-MEDIATED INTERACTIONS BETWEEN ABOVE- AND BELOW-GROUND COMMUNITIES

http://onlinelibrary.wiley.com/doi/10.1111/jec.2010.99.issue-1/issuetoc

Special Issue
Journal of Ecology

Ant-Plant Mutualism

 

 

Summary

1.  Mutualistic interactions are characterized by conditional outcomes that depend on both the biotic and the abiotic context. However, limited information is available on the factors that affect the strength of ant–plant interactions among sympatric congeneric species.
2.  We compared the benefits gained from attracting ants via extrafloral nectaries – i.e. lowered herbivory and increased seed set – of three co-occurring varieties in the Chamaecrista desvauxii complex (Leguminosae) in a cerrado area in Uberlândia, Brazil. Using whole-individual exclusion experiments, we tested the hypotheses (i) that the relative strength of those benefits is higher in the variety with the largest extrafloral nectaries and (ii) that those benefits are conditional on the presence of predispersal seed predators.
3. Extrafloral nectaries are larger, produce more nectar and attract more ants in var. brevipes than in the other two varieties included in the study. Var. modesta has intermediate-sized nectaries, while a third, undescribed variety has small nectaries, and both attract relatively few ants.
4. For var. brevipes, extrafloral nectary (EFN) removal significantly increased folivory and attack on fruits by sucking insects, decreasing the relative number of flowers, fruits and seeds produced per individual. For the other two varieties, in contrast, ant effects were reduced, and ants did not significantly improve reproductive success. In addition, effects of EFN removal were less pronounced or absent when seed predators were excluded from fruits of var. brevipes.
5.Synthesis. We showed experimentally that benefits from interactions of three co-occurring varieties of Chamaecrista desvauxii with ants are context-dependent both within and among taxa. Variation in the strength of mutualisms among sympatric taxa may potentially reinforce ecological reproductive isolation and contribute to diversification in this group.

Journal of Ecology

Volume 100, Issue 1, pages 242–252, January 2012

Thursday, 9 February 2012

The Seed Site

A website devoted entirely to seeds

Photographs
Seed Harvesting
Seed Sowing
Germination
Seedling Images
Database
Plant Profiles
Plant Index


Tuesday, 7 February 2012

Pflanzen als Vorbild für Roboter

http://www.heise.de/newsticker/meldung/Pflanzen-als-Vorbild-fuer-Roboter-1429208.html

On the German news, Plants as model samples for robots!!

How do wines coil around a support?


and how do seeds bury themselves into the ground?

Friday, 3 February 2012

A Clearer View from Fuzzy Images

Rather than having a single layer of photoreceptor cells, these eyes have a multitiered retina with four distinct photoreceptor layers. Nagata et al. investigated the spectral sensitivity of these retinal layers using a combination of molecular biology and electrophysiology. Opsins, a group of genes coding for specific color sensitivity (8, 9), were identified in the four retinal layers by gene sequencing, expression analysis, and in situ hybridization. Electrophysiology revealed that layers 1 and 2 are maximally sensitive to green light, whereas layers 3 and 4 are maximally sensitive in the ultraviolet. These sensitivities matched the identified opsin genes in the retinal layers. Curiously, however, even though layers 1 and 2 contain primarily green-sensitive photoreceptors, the effect of chromatic aberration means that incoming green light is only clearly focused on layer 1. This means that the second main green-sensitive retinal layer (layer 2) receives a defocused or “fuzzy” image. Nagata et al. suggest that the spiders obtain depth cues from the amount of defocus in this layer, which is proportional to the distance of the object to the lens.



Science 27 January 2012:
Vol. 335 no. 6067 pp. 409-410 


Depth Perception from Image Defocus in a Jumping Spider

Abstract

The principal eyes of jumping spiders have a unique retina with four tiered photoreceptor layers, on each of which light of different wavelengths is focused by a lens with appreciable chromatic aberration. We found that all photoreceptors in both the deepest and second-deepest layers contain a green-sensitive visual pigment, although green light is only focused on the deepest layer. This mismatch indicates that the second-deepest layer always receives defocused images, which contain depth information of the scene in optical theory. Behavioral experiments revealed that depth perception in the spider was affected by the wavelength of the illuminating light, which affects the amount of defocus in the images resulting from chromatic aberration. Therefore, we propose a depth perception mechanism based on how much the retinal image is defocused.  

Science 27 January 2012:
Vol. 335 no. 6067 pp. 469-471 

 

Bless you! - Gesundheit! - Salute!

"Bless you"
"Salute"
!!!!!!!!!!

Thursday, 2 February 2012

Floral Iridescence, Produced by Diffractive Optics, Acts As a Cue for Animal Pollinators

Abstract 
Iridescence, the change in hue of a surface with varying observation angles, is used by insects, birds, fish, and reptiles for species recognition and mate selection. We identified iridescence in flowers of Hibiscus trionum and Tulipa species and demonstrated that iridescence is generated through diffraction gratings that might be widespread among flowering plants. Although iridescence might be expected to increase attractiveness, it might also compromise target identification because the object's appearance will vary depending on the viewer's perspective. We found that bumblebees (Bombus terrestris) learn to disentangle flower iridescence from color and correctly identify iridescent flowers despite their continuously changing appearance. This ability is retained in the absence of cues from polarized light or ultraviolet reflectance associated with diffraction gratings. 






Full article


Science 2 January 2009:
Vol. 323 no. 5910 pp. 130-133
DOI: 10.1126/science.1166256 

The Origin of Modern Biodiversity: Coevolution of Flowers and Insects

Browsing the web, I came across this blog "Teaching Biology", where a very comprehensive description of coevolution of flowers and pollinators is presented!

I am not going to copy-paste the content on this post, so see the page using the link!


http://bioteaching.wordpress.com/

Wednesday, 25 January 2012

Rapid evolution of seed dispersal in an urban environment

Rapid evolution of seed dispersal in an urban environment in the weed Crepis sancta

P.-O. Cheptou, O. Carrue, S. Rouifed, A. Cantarel

Abstract

Dispersal is a ubiquitous trait in living organisms. Evolutionary theory postulates that the loss or death of propagules during dispersal episodes (cost of dispersal) should select against dispersal. The cost of dispersal is expected to be a strong selective force in fragmented habitats. We analyzed patchy populations of the weed Crepis sancta occupying small patches on sidewalks, around trees planted within the city of Montpellier (South of France), to investigate the recent evolutionary consequences of the cost of dispersal. C. sancta produces both dispersing and nondispersing seeds. First, we showed that, in urban patches, dispersing seeds have a 55% lower chance of settling in their patch compared with nondispersing seeds and, thus, fall on a concrete matrix unsuitable for germination. Second, we showed that the proportion of nondispersing seeds in urban patches measured in a common environment is significantly higher than in surrounding, unfragmented populations. Third, by using a quantitative genetic model, we estimated that the pattern is consistent with short-term evolution that occurs over ≈5–12 generations of selection, which is generated by a high cost of dispersal in urban populations. This study shows that a high cost of dispersal after recent fragmentation causes rapid evolution toward lower dispersal. 

 Read the article on PNAS

Upcoming Conferences in the Field of Biomimetics, Plant Biology & Plant Behaviour


11 – 13 June 2012
A Coruña, Spain
Deadline:


SEB Annual Main Meeting 2012

29th June - 2nd of July

Salzburg, Austria


Living Machines 2012

9th-12th July 2012
Barcelona, Spain  

 

Plant Biology Congress Freiburg 2012

July 29 - August 3, 2012

Freiburg


 

7th Plant Biomechanics International Conference 

20-24 August 2012

Clermont-Ferrand, France


1st Symposium on Plant Signaling and Behavior
16-21 September 2012
Perth - Western Australia



 63rd International Astronautical Congress
October, 1-5 2012
Napoli, Italy


The 3rd International Symposium on Biomimetics "bionik-A"

October, 17th and 18th 2012

Villach - Austria

Friday, 20 January 2012

How plants manipulate the scatter-hoarding behaviour of seed-dispersing animals




From the abstract:
Some plants that are dispersed by scatter-hoarding animals appear to have evolved the ability to manipulate the behaviour of those animals to increase the likelihood that seeds and nuts will be stored and that a portion of those items will not be recovered.

Plants have achieved this in at least four ways:
1. By producing large, nutritious seeds and nuts that are attractive to animals and that stimulate hoarding behaviour.
2. By imposing handling costs that cause animals to hoard rather than to eat items immediately. These handling costs can take one of two forms: physical barriers (e.g. hard seed coats) that take time to remove and secondary chemicals (e.g. tannins) that impose metabolic costs.
3. By masting, where a population of plants synchronizes reproductive effort, producing large nut crops at intervals of several years. Mast crops not only satiate seed predators, but also increase the amount of seed dispersal because scatter-hoarding animals are not easily satiated during caching (causing animals to store more food than they can consume) but are satiated during cache recovery.
4. By producing seeds that do not emit strong odours so that buried seeds are less likely to be discovered.

These, and perhaps other, traits have increased the relative success of plant species with seeds dispersed by scatter-hoarding animals.

Read the full paper!

Thursday, 19 January 2012

Swarming Behavior in Plant Roots

Marzena Ciszak 1,2, Diego Comparini 2, Barbara Mazzolai 3, Frantisek Baluska 4, F. Tito Arecchi 1,5, Tamás Vicsek 6, and Stefano Mancuso 2 from
(1) CNR-Istituto Nazionale di Ottica, Florence, Italy; (2) LINV-Department of Plant Soil & Environmental Science, University of Florence, Florence, Italy; (3) Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera (PI), Italy; (4) Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany; (5) Department of Physics, University of Florence, Florence, Italy; (6) Department of Biological Physics, Eötvös Loránd University, Budapest, Hungary.


Abstract
Interactions between individuals that are guided by simple rules can generate swarming behavior. Swarming behavior has been observed in many groups of organisms, including humans, and recent research has revealed that plants also demonstrate social behavior based on mutual interaction with other individuals. However, this behavior has not previously been analyzed in the context of swarming. Here, we show that roots can be influenced by their neighbors to induce a tendency to align the directions of their growth. In the apparently noisy patterns formed by growing roots, episodic alignments are observed as the roots grow close to each other. These events are incompatible with the statistics of purely random growth. We present experimental results and a theoretical model that describes the growth of maize roots in terms of swarming.


Thursday, 12 January 2012

Solar Botanic Renewable Energy Systems





SolarBotanic introduces artificial trees that make use of renewable energy from the sun and wind, they claim to be an efficient clean and environmentally sound means of collecting solar radiation and wind energy.
In this biomimicry concept their trees are fitted with Nanoleaves, a combination of Nano photovoltaic- Nanothermovoltaic and Nanopiezo generators converting light, heat and wind energy into green electricity.
Their nanoleaves convert the complete solar spectrum converting visible light, infrared and UV in combination with piezo electric generators that convert wind energy into electricity providing you with efficient, cost effective and aesthetic solutions, providing maximum electric power.

http://www.solarbotanic.com/