Calcium and reproduction go together

August 22, 2014

Everyone's heard of the birds and the bees. But that old expression leaves out the flowers that are being fertilized. The fertilization process for flowering plants is particularly complex and requires extensive communication between the male and female reproductive cells. New research from an international team from Stanford, Regensburg, Heidelberg, and Munich, and including Carnegie's Wolf Frommer, David Ehrhardt, and Guido Grossmann reports discoveries in the chemical signaling process that guides flowering plant fertilization. It is published in Nature Communications.

Flowering plants have a system. Grains of pollen carry the male reproductive cells. When pollen grains land on the flower's female reproductive organ, they germinate and grow towards the deeply embedded ovules via a pollen tube. After fertilization, ovules develop into seeds. What makes the process unique is that the pollen tube releases two sperm cells, one of which fuses with an egg in a process like that in animals. The other fuses with the so-called central cell to form a multi-nuclear entity that grows and provides nutrition for the developing embryo and seedling, respectively. This so-called endosperm is also the major source of nutrition for the animals and humans that eat these plants. Numerous cell-to-cell chemical interactions are necessary to guide this process as it takes place, many of which remain unidentified. In animals, calcium is key for communication between cells during fertilization. The research team, led by Thomas Dresselhaus from the University of Regensburg and Guido Grossmann, who recently moved from Carnegie to the University of Heidelberg, focused on finding calcium-facilitated communication in the double fertilization of flowering plants.

It was already known that calcium is involved in the early stages of fertilization, including growth control and the guidance that brings the sperm to the ovule. But more work was necessary to determine if it was as important in the later stages.

Using an advanced fluorescent calcium sensor the team was able to monitor calcium signatures in live cells throughout the whole double fertilization process. The work was performed using Arabidopsis, which is commonly used for research purposes. They found that calcium was involved in chemical signaling throughout the double fertilization process and is associated, for example, with sperm release and fusion with the egg cell. This type of real-time observation had previously been impossible due to the deeply imbedded location where double fertilization occurs.

"Thanks to technical advances we were able to observe the moment of plant fertilization at the cellular level and, at the same time, listen to the 'tête-à-tête' between male and female ," Grossmann said. "Further work is necessary to decode the language and understand what is actually being said."

Explore further: Biologists find unusual plant gene: abstinence by mutual consent

Related Stories

Plants spice up their sex life with defensins

June 1, 2010

Since the beginning, plants and animals have deployed various mechanisms to fight pathogens. Proteins have always played an important part in this armoury, and a broad variety of defensin proteins have become part of the ...

Pollination with precision: How flowers do it

May 17, 2012

Pollination could be a chaotic disaster. With hundreds of pollen grains growing long tubes to ovules to deliver their sperm to female gametes, how can a flower ensure that exactly two fertile sperm reach every ovule? In a ...

Recommended for you

Genomes uncover life's early history

August 24, 2015

A University of Manchester scientist is part of a team which has carried out one of the biggest ever analyses of genomes on life of all forms.

Rare nautilus sighted for the first time in three decades

August 25, 2015

In early August, biologist Peter Ward returned from the South Pacific with news that he encountered an old friend, one he hadn't seen in over three decades. The University of Washington professor had seen what he considers ...

Why a mutant rice called Big Grain1 yields such big grains

August 24, 2015

(Phys.org)—Rice is one of the most important staple crops grown by humans—very possibly the most important in history. With 4.3 billion inhabitants, Asia is home to 60 percent of the world's population, so it's unsurprising ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.