Home » Effect of Sunlight on Plant Growth

Effect of Sunlight on Plant Growth

Sun light is the primary source of energy for ecosystems. It is captured by plants through photosynthesis and its energy stored in the chemical bonds of organic compounds. Sunlight serves not only as an energy source for photosynthesis but also as a signal that regulates various growth and developmental processes, from seed germination to fruit development. Continue read to learn more about effect of sunlight on plant growth.

The quality (wavelength), the quantity (intensity) and the duration (photoperiod) of light influence photosynthesis and many growths and development features of plants.

effect of sunlight on plant growth

Figure 1: Effect of sunlight on plant growth

Quality of Light

The quality of light plays an important role in photosynthesis and photomorphogenesis (such as flower induction, seed germination and plant movements). In plants, photosynthesis occurs in the blue and red light. In terrestrial ecosystems, the quality of light does not change much. In aquatic ecosystems, the quality of light can be a limiting factor. Both blue and red light is absorbed and as a result, do not penetrate deeply into the water.

Light Intensity

The intensity of the light that reaches the Earth varies according to the latitude, season of the year and time of the day. Variation in intensity of light affects the processes of photosynthesis, growth & reproduction in plants. Plants, in general, can be divided into two groups: shade-tolerant species and shade-intolerant species. In ecology, shade tolerance refers to a plant’s ability to tolerate low light intensity.

Light Duration

The duration of light regulates the phenological process, such as flowering and fruiting, in plants. Plants use photoreceptors, such as phytochrome or cryptochrome, to sense photoperiod, which they take as signals for many growth and developmental processes.


FAQs on effect of sunlight on plant growth

Light from the sun powers photosynthesis, the process by which plants transform carbon dioxide and water into sugars and oxygen. Photosynthesis results in the production of carbohydrates, which are used for both vegetative and reproductive growth, as well as to increase the overall biomass of crops. Photosynthesis can only take place during the day because it requires energy from the sun.

The energy from the sun’s rays causes a chemical reaction that stows the carbon dioxide and water molecules. The byproduct of this reaction is glucose, a sugar, and oxygen. Chloroplasts are organelles that break down glucose and supply the plant with energy for growth and repair.

Plants respond differently to different colours of light, which can be used to their advantage. To give just one example, blue light is useful for promoting vegetative leaf growth. Combining red and blue light stimulates flowering in plants.

The amount of light available to a plant determines its ability to produce food, as well as its height, leaf colour, and flowering. Plants cultivated in dim conditions typically exhibit slender stature and pale green leaves. A comparable plant grown in intense sunlight will have shorter, stronger branches and larger, darker green leaves.