First of all, I think it is important to define
what a laser is. LASER is anacronym that stands for Light Amplification by the Stimulated Emission of Radiation.
According to several online definitions a laser is: A device that creates a uniform and coherent light that is very different from an ordinary light bulb. Many lasers deliver
light in an almost-perfectly parallel beam
(collimated) that is very pure, approaching a
single wavelength. Laser light can be focused down to a tiny spot as small as a single
Laser output can be continuous or pulsed and is used in a myriad of applications. In other words, lasers typically emit only one color of light(one wavelength or frequency), and
lasers often focus this light into a very narrow
There have been a few studies investigating the effects of different types of lasers on the growth and physiology of plants. One study I found exposed plants to UV-B ultraviolet radiation in order to damage their tissues. The scientists then exposed the plants to either He-Ne (helium-neon) lasers or to normal red light radiation. They found that the plants exposed to the lasers repaired their tissues more rapidly and grew faster after being damaged by ultraviolet compared to the plants exposed to red
radiation. This study indicated that certain
lasers can help plants recover from damage by
Another study suggested that red laser light can increase the growth of rice stalks, while blue laser light stimulates flowering of rice and the production of grain.
Some scientists are now working to find
combinations of blue and red lasers that maximize
the yield (grain production) and growth rates of
rice in a process called photonics.
In contrast, another view is that the high intensity light beams that lasers emit typically cause necrosis, or death, of plant tissues. In other words, if you shoot a laser at a plant, it will often leave a spot of dead plant tissue on the leaf where the laser energy contacted the plant.
Whether a laser harms a plant, assists its growth,
or has no affect probably depends on a number of
factors including the plant type, the tissue type (whether leaf, stem, root,etc.), the laser
wavelength (or frequency), the laser intensity
(number of photons per square cm per second), how
focused or narrow the laser beam is, and the
duration of time for which the plant is exposed to the laser.
I am not sure what studies have
looked at the effect of lasers on plant
growth through different objects.