Featured Research

from universities, journals, and other organizations

Why seedlings always grow towards the light

Date:
November 14, 2013
Source:
Wageningen University and Research Centre
Summary:
Scientists have discovered how cells in the stems of seedlings use blue light to grow towards the light. During earlier research the discovery was made that the cells in the seedling stems responded to blue light used in the microscope. The scientists have now discovered how the blue light causes small structures in the cell, the microtubules, to grow perpendicular to their normal growth direction.

Cells in the stems of seedlings use blue light to grow towards the light.
Credit: paylessimages / Fotolia

Scientists from the Carnegie Institution at Stanford University and Wageningen University have discovered how cells in the stems of seedlings use blue light to grow towards the light. During earlier research the discovery was made that the cells in the seedling stems responded to blue light used in the microscope.

The scientists have now discovered how the blue light causes small structures in the cell, the microtubules, to grow perpendicular to their normal growth direction. As a result, the growth direction of seedlings also changes, making them head towards the light. The scientists discovered which protein is responsible for making the microtubules grow perpendicular to the normal direction.

The results were published in Science.

Most people know that seedlings grow towards the light. But do they do that? It is a question that many scientists have wrestled with over the years. In earlier studies, scientists were looking into the cells of seedlings. Using special microscopes with blue laser light, they visualized the structures that are important for the growth direction of plant cells. Something surprising happened: within ten minutes, the arrangement of the microtubules changed completely under the microscope.

Through smart use of image analysis techniques, the scientists were able to show that -- within a few minutes -- blue light results in generation of large numbers of new microtubules which are all perpendicular to the pre-existing microtubules. They also discovered how the cells in seedlings detect the light in these conditions, namely through phototropin, one of the proteins that allow plants to detect light.

In addition, it was determined that the generation of large numbers of microtubules that are perpendicular to pre-existing microtubules is caused by the protein katanin. Seedlings that do not contain the katanin protein cannot make their microtubules change direction and are unable to grow towards the light. Katanin is activated by phototropin and can sever microtubules in half where they intersect other microtubules. Severing results in two microtubules each of which grow in the same orientation. Microtubules that are perpendicular to the pre-existing microtubules make many intersections. Every time new microtubules intersect with other microtubules positioned in the original direction, katanin can sever the new microtubules to create new branches. Within a few minutes, this results in 'trees' of microtubules within the cells that are perpendicular to the original direction.

The growth and development of plants depends strongly on the quality and quantity of light they detect. Plants depend on light for photosynthesis but are unable to move themselves. Instead, they grow towards the light. This study shows that the reorganisation of microtubules plays an essential role in this process.

The research was supported by an NSF award, the Carnegie Institution for Science, the Foundation for Fundamental Research on Matter (FOM), funded by the Netherlands Organisation for Scientific Research (NWO), the EU-NEST programme, a CASPIC award, the TOYOBO BIOFOUNDATION and the Human Frontier Science Programme.


Story Source:

The above story is based on materials provided by Wageningen University and Research Centre. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. J. Lindeboom, M. Nakamura, A. Hibbel, K. Shundyak, R. Gutierrez, T. Ketelaar, A. M. C. Emons, B. M. Mulder, V. Kirik, D. W. Ehrhardt. A Mechanism for Reorientation of Cortical Microtubule Arrays Driven by Microtubule Severing. Science, 2013; DOI: 10.1126/science.1245533

Cite This Page:

Wageningen University and Research Centre. "Why seedlings always grow towards the light." ScienceDaily. ScienceDaily, 14 November 2013. <www.sciencedaily.com/releases/2013/11/131114132102.htm>.
Wageningen University and Research Centre. (2013, November 14). Why seedlings always grow towards the light. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2013/11/131114132102.htm
Wageningen University and Research Centre. "Why seedlings always grow towards the light." ScienceDaily. www.sciencedaily.com/releases/2013/11/131114132102.htm (accessed July 30, 2014).

Share This




More Plants & Animals News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
Raw: Otters Enjoy Water Slides at Japan Zoo

Raw: Otters Enjoy Water Slides at Japan Zoo

AP (July 30, 2014) River otters were hitting the water slides to beat the summer heatwave on Wednesday at Ichikawa City's Zoological and Botanical Garden. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Rodents Rampant in Gardens Around Louvre

Rodents Rampant in Gardens Around Louvre

AP (July 29, 2014) Food scraps and other items left on the grounds by picnickers brings unwelcome visitors to the grounds of the world famous and popular Louvre Museum in Paris. (July 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins