Vegetables Man has been cultivating plants to

Vegetables are eaten everyday.

Through its history, Man has been cultivating plants to survive. Knowing how to
produce foods efficiently, our probability of surviving and quality of life has
increased. Improve of the efficiency of food production lasted for about fifty
years. However, today’s population explosion makes it harder for farmers to
meet demand. About 0.8 billion people are suffering from starvation, especially
those who are in developing countries. The problem has been getting worse year
by year. The global population is expected to grow to ten billion in next forty
years. If so, it is also expected that more than one billion people will be
starved. Many scientists have been studying more effective and easier way to
cultivate plants to solve food problems. In this context, our research focuses
on the appreciate relationship between light wavelength and light irradiation
time.

About light wavelength,
chlorophyll A and B in leaves is associated with plant growth because
chlorophyll absorb light and use this for photosynthesis. Figure1 is light
absorption spectrum of chlorophyll A and B. This shows that chlorophyll
is more likely to absorb light of about 450 nm and 650 nm wavelength, and more
to reflect the light between these wavelengths. 450nm light is blue, 550nm
light is green and 650nm light is red. Therefore the green light reach for
human eyes. C. S. Brown(1995) has reported that blue and
red color light have positive effect on plant growth