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Plant Science

Scientists present new data on the evolution of plants and the origin of species

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There are over 500,000 plant species in the world today. They all evolved from a common ancestor. How this leap in biodiversity happened is still unclear. An international team of researchers presents the results of a unique project on the evolution of plants. Using genetic data from 1,147 species the team created the most comprehensive evolutionary tree for green plants to date.

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Photosynthesis olympics: can the best wheat varieties be even better?

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Scientists have put elite wheat varieties through a sort of “Photosynthesis Olympics” to find which varieties have the best performing photosynthesis. This could ultimately help grain growers to get more yield for less inputs in the farm.

“In this study we surveyed diverse high-performing wheat varieties to see if their differences in photosynthetic performance were due to their genetic makeup or to the different environments where they were grown,” said lead researcher Dr Viridiana Silva-Perez from the ARC Centre of Excellence for Translational Photosynthesis (CoETP).

The scientists found that the best performing varieties were more than 30 percent better than the worst performing ones and up to 90 percent of the differences were due to their genes and not to the environment they grew in.

“We focused on traits related to photosynthesis and found that some traits behaved similarly in different environments. This is useful for breeders, because it is evidence of the huge potential that photosynthesis improvement could have on yield, a potential that hasn’t been exploited until now,” says Dr Silva-Perez.

During the study, published recently in the Journal of Experimental Botany, the scientists worked in Australia and Mexico, taking painstaking measurements in the field and inside glasshouses.

“The results that we obtained from our “Photosynthesis Olympics”, as we like to call them, are very exciting because we have demonstrated that there is scope to make plants more efficient, even for varieties working in the best conditions possible, such as with limited water and fertiliser restrictions. This means for example, that breeders have the potential to get more yield from a plant with the same amount of nitrogen applied,” says CoETP Director Professor Robert Furbank, one of the authors of this study.

Photosynthesis – the process by which plants convert sunlight, water and CO2 into organic matter – is a very complex process involving traits at different levels, from the molecular level, such as content of the main photosynthetic enzyme Rubisco, to the leaf, such as nitrogen content in the leaf and then to the whole canopy.

“This work is an important result for the CoETP, which aims to improve the process of photosynthesis to increase the production of major food crops such as wheat, rice and sorghum. There is a huge amount of collaboration, both institutional and interdisciplinary, that needs to take place to achieve this type of research. Without the invaluable cooperation between statisticians, plant breeders, molecular scientists and plant physiologists, we would have never achieved these results,” says co-author Tony Condon from CSIRO and the CoETP.

Read the paper: Journal of Experimental Botany

Article source: Arc Centre Of Excellence For Translational Photosynthesis

Author: Natalia Bateman

Image credit: Dr Viridiana Silva-Perez/COETP

Insect or virus? How plants know

By | News, Plant Health, Plant Science | No Comments

Most plants have plenty of enemies, from insects and other grazing creatures to various diseases, droughts and many other stressors.
Plants respond to injuries or illnesses by initiating various defense measures. But a viral infection requires a completely different response than desiccation, of course.
To know more about its attacker, the cell relies on mechanical and chemical signals.

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Carnivorous plant study captures universal rules of leaf making

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Leaves display a remarkable range of forms from flat sheets with simple outlines to the cup-shaped traps found in carnivorous plants.

A general question in developmental and evolutionary biology is how tissues shape themselves to create the diversity of forms we find in nature such as leaves, flowers, hearts and wings.

Study of leaves has led to progress in understanding the mechanisms that produce the simpler, flatter forms. But it’s been unclear what lies behind the more complex curved leaf forms of carnivorous plants.

Previous studies using the model species Arabidopsis thaliana which has flat leaves revealed the existence of a polarity field running from the base of the leaf to the tip, a kind of inbuilt cellular compass which orients growth.

To test if an equivalent polarity field might guide growth of highly curved tissues, researchers analysed the cup-shaped leaf traps of the aquatic carnivorous plant Utricularia gibba, commonly known as the humped bladderwort.

The team of Professor Enrico Coen used a combination of 3D imaging, cell and clonal analysis and computational modelling to understand how carnivorous plant traps are shaped.

These approaches showed how Utricularia gibba traps grow from a near spherical ball of cells into a mature trap capable of capturing prey.

By measuring 3D snapshots of traps at various developmental stages and exploring computational growth models they showed how differential rates and orientations of growth are involved.

The team used fluorescent proteins to monitor cellular growth directions and 3D imaging at different developmental stages to study the changing shape of the trap.

The computational modelling used to account for oriented growth invokes a polarity field comparable to that proposed for Arabidopsis leaf development, except that here it propagates within a curved sheet.

Analysis of the orientation of quadrifid glands, which in Utricularia gibba are used for nutrient absorption, confirmed the existence of the hypothesised polarity field.

The study which appears in the Journal PLOS Biology concludes that simple modulation of mechanisms underlying flat leaf development can also account for shaping of more complex 3D shapes.

One of the lead authors Karen Lee said, “A polarity field orienting growth of tissue sheets may provide a unified explanation behind the development of the diverse range of leaves we find in nature.”

The study, done in collaboration with the group of Minlong Cui at Zhejiang University in China

Read the paper: PLOS Biology

Article source: John Innes Centre

Image credit: Karen Lee, Yohei Koide, John Fozard and Claire Bushell.