Explore Plants

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 

Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.

rate this answer
11 ratings

Thursday - June 09, 2005

From: toronto, NV
Region: Select Region
Topic: General Botany
Title: Smarty Plants on cell elongation
Answered by: Joe Marcus

QUESTION:

Why do plants grow faster in the dark?

ANSWER:

In a strict sense, plants do not grow faster in the dark; they grow slower. However, plants seem to grow faster in insufficient light due to rapid cell elongation. In other words, they don't grow faster, they simply stretch. It is important to know that green plants really only grow as a result of photosynthetic processes. Without light photosynthesis ceases and plant tissue develop the characteristic, low-light induced sickly green or white coloration.

Rapid elongation of plant cells in low-light conditions is an emergency response on the part of the plant to return its plant tissues to the light where they can again photosynthesize and live. This would be analagous to standing on the bottom of a swimming pool and stretching to get your nose above water for a breath of life-giving oxygen.

In conditions of total darkness, plant cells will generally expand upward, a process called geotropism. In conditions where a small amount of light is reaching the plant, it will grow toward the brightest source of light in a process called heliotropism. Prolonged exposure to darkness will inevitably lead to the death of a plant.
 

More General Botany Questions

Percentage of flowers that close up at night
July 19, 2007 - Percentage-wise, approximately how many species of flowers close up at night? Is there a list anywhere?
view the full question and answer

Comments on white-flowered Mountain Laurel from Austin
December 23, 2012 - Following up on the August 23, 2012, question from Driftwood about the white-flowering mountain laurel, I have found a few more leads to explore. First, there are four more images of white-flowering m...
view the full question and answer

What is a Demaree Rose?
August 14, 2013 - Have been told the Apache Plume is the Wild Rose after which the Wild Rose Pass north of Ft. Davis was named. However, other research indicates it was the Demaree Rose. What is true and are there ...
view the full question and answer

Is Phlox divaricata evergreen?
June 27, 2011 - Is Phlox divaricata evergreen?
view the full question and answer

Rotten Oranges
June 03, 2009 - Do oranges rot if they are not taken off the tree when ripe?
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.