The Lord Howe screw pine is a self-watering island giant



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To grow tall enough to reach the canopy, a species of screw pine unique to Lord Howe Island has evolved its own rainwater harvesting system.
Matthew Biddick, CC BY-SA

Matthew Biddick, Victoria University of Wellington

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Pandanus forsteri, a species of screw pine endemic to Lord Howe Island, grows tall like no other tree on Earth. To reach the canopy, these trees have evolved a rainwater harvesting system that enables them to water themselves.

Originally from Micronesia, the palm-like P. forsteri belongs to a group of trees that have populated almost every coastal habitat of the Pacific. In fact, pandans are used by Oceanic cultures for everything from fishing and cooking to medicine and religious ceremonies.

Our research shows that pandans differ in several fundamental ways from more familiar trees, including how they capture water and grow.




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Welcome to Beating Around the Bush, wherein we yell about plants


Reaching for the canopy

Most trees lay down concentric rings of vascular tissue as they mature, thickening over time. This enables them to grow tall, yet maintain enough structural integrity to avoid toppling over. It is also arguably the most important evolutionary innovation that has enabled trees to colonise most of terrestrial Earth.

Together with palms, bamboo and yucca, pandans belong to a group known as monocots, because their seedlings produce a single embryonic leaf.

Pandans belong to a group of plants whose vascular tissue is still primitive, making it difficult to grow tall.
Ian Hutton, CC BY-SA

Their vascular tissue is not compartmentalised in the same way. It forms bundles that are positioned somewhat haphazardly within the stem. Consequently, monocots are unable to produce true secondary growth and thicken like other trees do – and reaching the canopy becomes a much more ambitious endeavour.

The canopy offers a good life. The sun is shining, seed-dispersing birds are abundant, and the herbivores of the forest floor are a distant concern. In monocots, natural selection has favoured some inventive ways of stretching to the top.

Pay-as-you-go growth

Palms overcome the limitations imposed by their physiology by spending their younger years laying down enough vascular girth to support their future stature. Think of it like putting aside money for your retirement. You may not need it now, but you will likely later depend on it.

Stilt roots support the crown as it matures.
Kevin Burns, CC BY-SA

Once thick enough, palms shift their efforts to vertical growth. The palm’s tactic of delayed vertical growth may be slow, but it functions well enough to thrust Columbian wax palms (Ceroxylon quindiuense) – the world’s tallest monocot – 45 meters into the clouds.

Pandans, on the other hand, are less patient. Unlike palms, they prefer a sort of “pay-as-you-go” method. They produce stilt roots that extend from the trunk to the ground for support as the crown matures. The end result gives the appearance of an ice cream cone perched on a tepee of stilts. It’s an odd strategy, but it works.

However, on Lord Howe Island, something quite remarkable has transpired. Isolated some 600 kilometres off the east coast of Australia, one species of screw pine has evolved into an island giant.

Lord Howe Island, some 600km off the Australian east coast, is home to countless endemic plants and animals.
Ian Hutton, CC BY-SA

Island syndrome

Most screw pines are lucky to reach four or five meters. Pandanus forsteri trees, however, regularly exceed 15 meters. These kinds of size changes are not uncommon on isolated islands. They are part of a repeated evolutionary phenomenon known as the island syndrome.

Species on isolated islands are free from the stressors of continental life, and they subsequently converge on a more optimal, ancestral form. Large continental species evolve into island dwarfs, while smaller species become comparatively gigantic. Support for the island syndrome primarily comes from animals. However, a growing body of evidence suggests island plants follow a similar evolutionary path.




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A network of aqueducts on the root surface guides water to the absorptive tissue at the tip of the growing root.
Matt Biddick, CC BY-SA

While gigantism may be favourable, it doesn’t come without risks – and for P. forsteri, they are serious. Thanks to their new-found stature, P. forsteri trees must produce enormous stilt roots to support themselves. This process that can take years. Exposed to the air, roots can form air bubbles, and an air bubble in a plant is bad in the same way it is bad in your artery. It is potentially lethal.

Nature appears to have solved this problem through the evolution of a rainwater harvesting system that enables P. forsteri to water its own stilt roots before they reach the ground.

Gutter-like leaves collect rainwater and transport it to the trunk, where it descends. The flow of water is then couriered by a network of aqueducts formed by the root surface. Finally, water is stored in a specialised organ of absorptive tissue encasing the growing root tip.

Back to the drawing board

This is dramatically different from how we traditionally think about plants. It is far from our concept of sessile beings that passively absorb everything they need from the soil, thanks to the capillary action of their vascular tissues. Never before has a plant species been shown to possess a system of traits that operate jointly to capture, transport and store water external to itself.

This species has opened our eyes to an entirely new field of scientific inquiry. It forces scientists to rethink the function of organs like leaves and roots outside of the contexts of photosynthesis and the conduction of soil water.

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The Conversation

Do other plants harvest rainwater in this way? Why have we only just discovered this? Has our overly simplistic view of plants hindered our ability to comprehend their true complexity? Only time, and more research, will tell.

Matthew Biddick, PhD Researcher, Victoria University of Wellington

This article was originally published on The Conversation. Read the original article.

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How hydrogen power can help us cut emissions, boost exports, and even drive further between refills



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Could this be the way to fill up in future?
CSIRO, Author provided

Sam Bruce, CSIRO

Hydrogen could become a significant part of Australia’s energy landscape within the coming decade, competing with both natural gas and batteries, according to a new CSIRO roadmap for the industry.

Hydrogen gas is a versatile energy carrier with a wide range of potential uses. However, hydrogen is not freely available in the atmosphere as a gas. It therefore requires an energy input and a series of technologies to produce, store and then use it.

Why would we bother? Because hydrogen has several advantages over other energy carriers, such as batteries. It is a single product that can service multiple markets and, if produced using low- or zero-emissions energy sources, it can help us significantly cut greenhouse emissions.

Potential uses for hydrogen.
CSIRO, Author provided

Compared with batteries, hydrogen can release more energy per unit of mass. This means that in contrast to electric battery-powered cars, it can allow passenger vehicles to cover longer distances without refuelling. Refuelling is quicker too, and is likely to stay that way.

The benefits are potentially even greater for heavy vehicles such as buses and trucks which already carry heavy payloads, and where lengthy battery recharge times can affect business models.




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Hydrogen can also play an important role in energy storage, which will be increasingly necessary both in remote operations such as mine sites, and as part of the electricity grid to help smooth out the contribution of renewables such as wind and solar. This could work by using the excess renewable energy (when generation is high and/or demand is low) to drive hydrogen production via electrolysis of water. The hydrogen can then be stored as compressed gas and put into a fuel cell to generate electricity when needed.

Australia is heavily reliant on imported liquid fuels and does not currently have enough liquid fuel held in reserve. Moving towards hydrogen fuel could potentially alleviate this problem. Hydrogen can also be used to produce industrial chemicals such as ammonia and methanol, and is an important ingredient in petroleum refining.

Further, as hydrogen burns without greenhouse emissions, it is one of the few viable green alternatives to natural gas for generating heat.

Our roadmap predicts that the global market for hydrogen will grow in the coming decades. Among the prospective buyers of Australian hydrogen would be Japan, which is comparatively constrained in its ability to generate energy locally. Australia’s extensive natural resources, namely solar, wind, fossil fuels and available land lend favourably to the establishment of hydrogen export supply chains.

Why embrace hydrogen now?

Given its widespread use and benefit, interest in the “hydrogen economy” has peaked and troughed for the past few decades. Why might it be different this time around? While the main motivation is hydrogen’s ability to deliver low-carbon energy, there are a couple of other factors that distinguish today’s situation from previous years.

Our analysis shows that the hydrogen value chain is now underpinned by a series of mature technologies that are technically ready but not yet commercially viable. This means that the narrative around hydrogen has now shifted from one of technology development to “market activation”.

The solar panel industry provides a recent precedent for this kind of burgeoning energy industry. Large-scale solar farms are now generating attractive returns on investment, without any assistance from government. One of the main factors that enabled solar power to reach this tipping point was the increase in production economies of scale, particularly in China. Notably, China has recently emerged as a proponent for hydrogen, earmarking its use in both transport and distributed electricity generation.

But whereas solar power could feed into a market with ready-made infrastructure (the electricity grid), the case is less straightforward for hydrogen. The technologies to help produce and distribute hydrogen will need to develop in concert with the applications themselves.

A roadmap for hydrogen

In light of this, the primary objective of CSIRO’s National Hydrogen Roadmap is to provide a blueprint for the development of a hydrogen industry in Australia. With several activities already underway, it is designed to help industry, government and researchers decide where exactly to focus their attention and investment.

Our first step was to calculate the price points at which hydrogen can compete commercially with other technologies. We then worked backwards along the value chain to understand the key areas of investment needed for hydrogen to achieve competitiveness in each of the identified potential markets. Following this, we modelled the cumulative impact of the investment priorities that would be feasible in or around 2025.


CSIRO, Author provided

What became evident from the report was that the opportunity for clean hydrogen to compete favourably on a cost basis with existing industrial feedstocks and energy carriers in local applications such as transport and remote area power systems is within reach. On the upstream side, some of the most material drivers of reductions in cost include the availability of cheap low emissions electricity, utilisation and size of the asset.




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The development of an export industry, meanwhile, is a potential game-changer for hydrogen and the broader energy sector. While this industry is not expected to scale up until closer to 2030, this will enable the localisation of supply chains, industrialisation and even automation of technology manufacture that will contribute to significant reductions in asset capital costs. It will also enable the development of fossil-fuel-derived hydrogen with carbon capture and storage, and place downward pressure on renewable energy costs dedicated to large scale hydrogen production via electrolysis.

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The Conversation

In light of global trends in industry, energy and transport, development of a hydrogen industry in Australia represents a real opportunity to create new growth areas in our economy. Blessed with unparalleled resources, a skilled workforce and established manufacturing base, Australia is extremely well placed to capitalise on this opportunity. But it won’t eventuate on its own.

Sam Bruce, Manager, CSIRO Futures, CSIRO

This article was originally published on The Conversation. Read the original article.