The Effects of Light on Tagetes patula

Памер79.5 Kb.
The Effects of Light on Tagetes patula Growth

A research proposal for Biological Communications

(Biol 3920)

Principal Investigator: Amber Jones

Undergraduate Student

Biology Dept.

Tennessee Technological University

Cookeville, TN 38505


Table of Contents

Pg.3 - Project summary; key words

Pg. 4 - Introduction
Pg. 5-7 - Methods and materials; data form
Pg. 8 - Expected results and benefits
Pg. 9 - Timeline
Pg. 10 - Disseminating research results
Pg. 11 - Literature cited
Pg. 12 - Budget

Project Summary

Plants need light to grow. The problem that I am exploring is whether or not the type of light a plant receives will effect the growth of the plant; specifically Tagetes patula, a type of dwarf marigold.

My objective is to determine if Tagetes patula growth is effected by the type of light that the plant is grown in. My hypothesis is that Tagetes patula will grow better in natural (sun) light than in artificial (incandescent) light.

I plan to accomplish my goal by growing Tagetes patula in an experiment to test under which light source the plant type will thrive best. Two groups of Tagetes patula will be grown with only one light source for each; one with sunlight only and one with incandescent light only.

My expected results are that the Tagetes patula grown in the sunlight will grow better in a noticeable way; perhaps faster, larger and/or more hearty than the Tagetes patula grown in incandescent lighting.

Key Words: incandescent, light type, marigold, plant growth, sunlight, Tagetes patula


“Light…supplies the energy upon which plant life is based…The effects of light quality on plant life are manifold (Stolwijk & Wassink)”. The fact that plants need light to run the processes necessary for their survival is commonly known and has been studied extensively. As Stolwijk stated it supplies their energy and “also plays an important role in directing this energy along the various possible metabolic pathways.” Light would almost always be a large factor in any type of experiment done with plant life. “Effects of light quality on various phases of growth and development have been studied in almost every major group of plants.”

Plants need light to survive and my experiment examines which light type yields better growth in Tagetes patula. I hypothesize that Tagetes patula will grow better in sunlight than in incandescent light because of the difference in the light quality. My null hypothesis is that there will be no difference in plant growth whether Tagetes patula is grown in sunlight or incandescent light which would result in the conclusion that there is no difference in the quality of the two light types.

Methods and Materials

Research subject is the plant Tagetes patula a type of dwarf marigold. The materials used were 2 Ferry-Morse peat pellet trays, Ferry-Morse marigold seeds, tap water, miracle grow, Ferry-Morse plant labels, a plastic syringe, a sharpie, a gallon plastic jug, and a small votive candle holder.

Each peat pellet tray contained 12 peat pellets, 3 seeds were planted in 4 pellets, 5 seeds in 4 pellets and 8 seeds in 4 pellets, this process was done for both subject groups (trays). The sections of the trays were labeled as follows: the 4 pellets containing 3 seeds in Test Group 1 (Sunlight only) were marked G1S3 for Group 1 Seeds 3 on the label stick with a sharpie, the 4 pellets containing 3 seeds in Test Group 2 (Incandescent only) were marked G2S3 for Group 2 Seeds 3 and so on with the pellets containing 5 and 8 seeds for each group. One tablespoon of Miracle grow flower food was added to one gallon of tap water and as the experiment was conducted each pellet received 4 cc of this water every other day. The plants sprouted on day 5 after being sown and were watered the first time on day 6. The water/fertilizer mixture was added to the pellets by pouring an amount from the jug into a small candle holder for easier access, withdrawing 4 cc from the candle holder with the plastic syringe and watering each pellet in turn.

The only variable in the experiment was the light source all other factors were the same for each test group including time of exposure to each type of light. The experiment was performed in my home, Test Group one placed on a windowsill and treated without being exposed to incandescent lighting and Test Group two treated in an internal room (a bathroom) that received no sunlight.

Data is to be processed by harvesting the plants from each group and comparing their average stem heights per pellet seed # group (3, 5 and 8), average number of leaves per plant per pellet seed # group and average number of plants per pellet per seed # group. (Brown 2008)

Expected Results and Benefits

The expected results are that Tagetes patula will grow better in sunlight than in artificial light which will refute the null hypothesis by proving that there is a difference in plant growth when grow in different light types.

Benefits are finding out which light type Tagetes patula grows best in to aid in the growth of healthier, heartier marigolds.

Disseminating Research Results

Research could be communicated by giving a presentation of my experiment and results or writing a research paper for my experiment and results and having it reviewed and published.

Literature Cited

Stolwijk, J. A. J., and E. C. Wassink. 1956. Effects of Light Quality on Plant Growth. Annual Review of Plant Physiology 7: 373-400.













*Included in wages is cost of water and electricity for experiment.
Jug, sharpie, syringe and candle holder were free materials I found around my house.

Поделитесь с Вашими друзьями:

База данных защищена авторским правом © 2022
звярнуцца да адміністрацыі

    Галоўная старонка