stems

Fighting Disease in Cavendish Bananas | Earth Wise

January 31, 2022 By EarthWise Leave a Comment

Cavendish bananas account for about half of global banana production and the vast majority of bananas entering international trade. The plant is unable to reproduce sexually and instead is propagated via identical clones. So, the genetic diversity of the Cavendish banana is exceedingly low.

In 2008, Cavendish cultivars in Sumatra and Malaysia started to be attacked by Panama disease, a wilting disease caused by a fungus. In 2019, Panama disease was discovered on banana farms in the coastal Caribbean region, its first occurrence in the Americas. In the 1950s, Panama disease wiped out the Gros Michel banana, the commercial predecessor of the Cavendish.

Scientists at the University of Cambridge have found a novel way to combine two species of grass-like plants – which include bananas, rice, and wheat – using embryonic tissue from their seeds. The technique allows beneficial characteristics, such as disease resistance, to be added to the plants.

Joining the shoot of one plant to the root of another to grow as one plant is known as grafting. It was thought to be impossible to do with grass-like plants – called monocotyledonous grasses – because they lack a certain tissue type in their stems. But the new research, published in the journal Nature, showed it can be done with the plants in their earliest embryonic stages.

Cavendish bananas are sterile, so disease resistance can’t be bred into future generations. But the grafting technique may provide a way to produce Cavendish banana plants that are resistant to Panama disease. It may be possible to save an important food crop before it is too late.

**********

Web Links

New grafting technique could combat the disease threatening Cavendish bananas

Photo, posted July 1, 2015, courtesy of Augustus Binu via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Restoring Seagrass In Virginia | Earth Wise

December 10, 2020 By EarthWise Leave a Comment

Seagrass is found in shallow waters in many parts of the world. They are plants with roots, stems, and leaves, and produce flowers and seeds. They can form dense underwater meadows that constitute some of the most productive ecosystems in the world. Seagrasses provide shelter and food to a diverse community of animals including tiny invertebrates, fish, crabs, turtles, marine mammals and birds.

In the late 1920s, a pathogen began killing seagrasses off the coast of Virginia. In 1933, a hurricane finished them off completely. For nearly 70 years thereafter, the bay bottoms of the Virginia coast were muddy and barren, essentially devoid of fish, shellfish, mollusks and other creatures that inhabit seagrass meadows. The local scallop industry was no more.

The largest seagrass restoration project ever attempted has changed all that. During the past 21 years, scientists and volunteers have spread more than 70 million eelgrass seeds within four previously barren seaside lagoons. This has spurred a natural propagation of meadows that have so for grown to almost 9,000 acres, the largest eelgrass habitat between North Carolina and Long Island Sound.

The long-term research conducted by the team from the University of Virginia shows that the success of the seagrass restoration project is improving water quality, substantially increasing the abundance of fish and shellfish in the bays, and capturing carbon from the water and atmosphere and storing it in the extensive root systems of the grasses and in the sediment below.

The study shows that marine restorations are possible on scales that contribute directly to human well-being.

**********

Web Links

Some Good News: Seagrass Restored to Eastern Shore Bays is Flourishing

Photo, posted May 17, 2019, courtesy of Virginia Sea Grant via Flickr. Photo credit: Aileen Devlin | Virginia Sea Grant.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving Beaches With Seagrass

February 22, 2019 By EarthWise Leave a Comment

Almost a quarter of the Gross Domestic Product of places around the Caribbean Sea is earned from tourism. Preserving the beaches in the region is an economic imperative. With increasing coastal development, the natural flow of water and sand is disrupted, natural ecosystems are damaged, and many tropical beaches simply disappear into the sea.

With such high stakes, expensive coastal engineering efforts such as repeated replenishing of sand and the construction of concrete protective walls are common strategies. Rising sea levels and increasingly powerful storms only increase the threat to tropical beaches.

Researchers from The Netherlands and Mexico recently published a study in the journal BioScience on the effectiveness of seagrass in holding onto sand and sediment along shorelines.

Seagrasses are so-named because most species have long green, grass-like leaves. They are often confused with seaweeds but are actually more closely related to flowering plants seen on land. Seagrasses have roots, stems and leaves, and produce flowers and seeds. Seagrasses can form dense underwater meadows and are one of the most productive ecosystems in the world. Seagrasses provide shelter and food to an incredibly diverse community of animals, from tiny invertebrates to large fish, crabs, turtles, marine mammals and birds.

The researchers performed measurements of the ability of seagrass along Mexico’s Yucatan Peninsula coastline to keep sand in place and prevent erosion. They found that the amount of erosion was strongly linked to the amount of vegetation. Quite often, seagrass beds have been regarded as a nuisance, rather than a valuable asset for preserving valuable coastlines. The study opens opportunities for developing new tropical beach protection schemes in which ecology is integrated into engineering solutions.

**********