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TITLE The germination behaviour of Azuki bean seeds (Vigna angularis) towards microgravity

AIM -To investigate the germination behaviour of Azuki bean seeds (Vigna angularis) in simulatedmicrogravity environment

-To determine the effect of potassium nitrate, KNO3 towards germination of seed

PROBLEMSTATEMENT /

RESEARCHQUESTION

What are the effects of simulated microgravity environment and potassium nitrate, KNO3 towards thegermination of Azuki bean seeds?

LITERATUREREVIEW

The Factors Affecting the Rate of Germination

There are four major factors affecting the germination process of seeds, which are gravity, light,temperature, air and moisture.

Hideyuki Takahashi says that a microgravity environment has a great impact on plant growth anddevelopment, and it eventually affects plant yield. It is said that the shape of the living organisms fromthe Earth is influenced by the planet's gravitational environment.

When the gravitational environment is removed (microgravity environment), some organisms willshow automorphogenesis. To create a microgravity environment, a 3D clinostat can be used, whichsimulated microgravity by rotating the seeds. On Earth, aerial parts of the plant (shoots) grow upwardwhile roots grow downward.

However, in microgravity environment, the growth direction is unregulated, and some roots evenextend in the same direction as the aerial stems. When compared, the shoots of the seeds on a normalgravitational environment grows straight, but on the other hand, the shoots of the seeds on amicrogravity environment will bend. Therefore, gravitational environment do affect the germinationprocess of seeds.

Besides, light is another major factor affecting seeds germinations. Heather Jerret and Delia Gillenssaid that light has varied effects on germinating seeds of different plants. Some seeds need light forgermination, while in some seeds germination is hindered by light.

Most wild species of flowers and herbs prefer darkness for germination and should be planteddeep in the soil while most modern vegetable crops prefer light or are not affected by it, and areplanted shallowly to allow small amounts of light to filter through the soil.

According to Victoria Lee Blackstone, some seeds, such as the sunflower and pelargoniums musthave darkness for successful germination. These seeds are sown directly into the ground and coveredwith soils. On the other hand, some seeds, for example the impatiens and petunia seeds need to besurface-sown to allow exposure to light. If these seeds are not covered, germination will not occur.

However, David Batty explained that other factors can also affect the seeds light requirement. Forexample, with some species (e.g. Salvia pretences and Saxifraga caespitosa) light requirement only exists

immediately after harvesting whereas with Salvia verticillata and Apium graveolens (Celery) this lasts fora year and to confuse matters further other species develop a light requirement while in storage.Chemicals also, such as nitrates in the soil, can substitute for light in stimulating seeds to germinate so

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that some light requiring seeds will still germinate if covered with fertile soil.

According to Wikipedia (en.wikipedia.org), Seeds from different species and even seeds from the sameplant germinate over a wide range of temperatures. Seeds often have a temperature range within whichthey will germinate, and they will not do so above or below this range. Many seeds germinate attemperatures slightly above 60-75 F (16-24 C) [room-temperature if you live in a centrally heatedhouse], while others germinate just above freezing and others germinate only in response to

alternations in temperature between warm and cool. Some seeds germinate when the soil is cool 28-40F (-2 - 4 C), and some when the soil is warm 76-90 F (24-32 C).

Heather Jerret as well as Delia Gillens also thought that germination can take place over a widerange of temperature and is specific to individual crop types, and can be specific to varieties. They say,the optimum for most crops is between 65-75F, but exceptions do apply.

Jacob J. Wright, on the other hand tells that at standard, the temperature for general bean seeds isat 70 degree Fahrenheit (21 degree Celsius), but each bean species may need different soiltemperatures for germination, based on adaptations to where they are native.

As for moisture, Heather Jerret and Delia Gillens said that a dormant seed only contains 10-15% ofwater and is essentially dehydrated. In order to become active, the seed has to absorb water. It isimbibed by the seed coat and enzymes within the seed become active and functional, metabolizingstored food reserves. The embryo then begins to swell. The softened seed coat ruptures as the seedgrows too big for its encasement and germination has commenced. This shows that without water,seeds cannot germinate.

Jacob J. Wright says that even though a bean seed feels and looks dry, minute amounts of moisturewithin the seed keep the dormant embryo alive. For the embryo to grow, some external water sourcecauses the hard testa to soften and split and trigger metabolism in the dormant embryo. Water entersthe seed in a tiny hole in the testa called the micropyle.

He again tells that a delicate balance exists in the appropriate amount of water necessary for beanseed germination. Too little moisture and the seed begins to sprout but then dries up and dies; toomuch water and the embryo dies and rots.

During germination, air is another factor that could affect the whole germination process. Heathersays in the dormant condition the seeds respiratory rate is very low and so oxygen is required in verysmall quantities. But for germination, oxygen is needed in large quantities. The seeds obtain oxygen thatis dissolved in water and from the air contained in the soil. If soil conditions are too wet, an anaerobic

condition persists, and seeds may not be able to germinate.

Furthermore, Jacob J. Wright tells that plants absorb carbon dioxide from the atmosphere, butplants also need oxygen to metabolize food and to grow. During germination, air must reach embryoand that is why a moist but crumbly, loose soil environment promotes best germination.

Last but not least, germination process can be affected when the seeds are soaked in different solutionas a pre-treatment for the seeds. By soaking the seeds, this treatment can stimulate the rate ofgermination of seeds, which then make them to germinate faster.

According to rhodielady_47, Salt Petre, also known as potassium nitrate, (KNO3) is often used tostimulate germination of dormant or irregular seeds. The seeds are soaked in a 1000 to 3000ppmsolution (1 - 3 grams per litre), or are germinated on pads soaked in this solution. Seeds remain dormantto ensure the best conditions for germination. Basically, potassium nitrate helps to break the seeds

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dormancy, and therefore, encouraging the seeds to germinate faster.

HYPOTHESIS -The Azuki bean seedlings show automorphogenesis.

- Pre-soaking seeds in potassium nitrate, KNO3 solution increases the rate of germination of Azuki beanseeds (Vigna angularis).

VARIABLES MANIPULATED -Simulated microgravity

RESPONDING -The length of radicle and plumule

-The suppleness of the stem

CONSTANT -Type of beans

-Room temperature

-Volume of water

-Duration of germination

APPARATUS 250ml beaker, forceps, 10ml measuring cylinder, container (21cm 15cm 4cm), opaque box,thermometer, cutter knife, ruler, volumetric flask.

MATERIALS Distilled water, Azuki bean seeds (Vigna angularis), 0.1% potassium nitrate, KNO3 solution, rockwoolblocks (3cm 3cm 3cm), graph paper, plasticine clay, gloves, thread, and label paper.

PROCEDURE

Figure 1, the apparatus set-up of the experiment

1. On Day 1, 18 Azuki beans are pre-soaked in 100ml of 0.1% potassium nitrate, KNO3 solution in abeaker.

2. After 30 minutes, the seeds are brought out and rinsed with distilled water.3. Three holes are made on each rock wool block with a knife.4. The rinsed seeds are placed on the rock wools securely with the hilum facing upwards.5. All the seeded rockwool blocks are placed into the plastic container and fitted with the

plasticine. The plasticine is used to avoid the rockwool blocks from falling off the container

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horizontal to the surface of the earth.

Basically, microgravity causes automorphogenesis and growth direction of plumule and radicle to beunregulated or others call it curvatures.

Another factor which is pre-soaking treatment is widely used in the agriculture industry. In thisexperiment, the Azuki bean seeds are pre-soaked in potassium nitrate, KNO3 solution before it isplanted into the rock wools to stimulate the growth of the radicle. Potassium nitrate is one of severalnitrogen-containing compounds which majorly used as a fertilizer. Usually, a seed takes 3-5 days togerminate after it is planted. However, this experiment is conducted for 7 days only. Therefore, thegermination of the radicles and plumules need to be stimulated by soaking it in potassium nitrate, KNO3solution which is widely used in germinating seeds. When the growth of radicle is stimulated, the seedswill sprout quickly and the effects of microgravity towards the radicle and plumule can be seen moreapparently.

CONCLUSION The Azuki bean seedlings (Vigna angularis) show automorphogenesis and the rate of germination of theseeds increased when pre-soaked in potassium nitrate, KNO3 solution.

Hypothesis are accepted.

REFERENCES http://www.ncbi.nlm.nih.gov/pubmed/11538807 ,

http://link.springer.com/article/10.1007%2FBF00008074 ,

http://www.kiwispace.org.nz/display/SSAF/Hypothesis+1+-+Automorphogenesis

http://www.jaxa.jp/article/special/kibo/takahashi_e.html

http://www.researchgate.net/publication/11803400_Autotropism_automorphogenesis_and_gravity

http://www.highmowingseeds.com/sb-factors-affecting-germination-of-organic-seeds.html

http://forums.gardenweb.com/forums/load/tomato/msg0317254629885.html

http://www.thompson-morgan.com/effect-of-light

http://www.iss.jaxa.jp

http://www.ncbi.nlm.nih.gov/pubmed/11538807http://www.ncbi.nlm.nih.gov/pubmed/11538807http://link.springer.com/article/10.1007%2FBF00008074http://link.springer.com/article/10.1007%2FBF00008074http://www.kiwispace.org.nz/display/SSAF/Hypothesis+1+-+Automorphogenesishttp://www.kiwispace.org.nz/display/SSAF/Hypothesis+1+-+Automorphogenesishttp://www.jaxa.jp/article/special/kibo/takahashi_e.htmlhttp://www.jaxa.jp/article/special/kibo/takahashi_e.htmlhttp://www.researchgate.net/publication/11803400_Autotropism_automorphogenesis_and_gravityhttp://www.researchgate.net/publication/11803400_Autotropism_automorphogenesis_and_gravityhttp://www.researchgate.net/publication/11803400_Autotropism_automorphogenesis_and_gravityhttp://www.highmowingseeds.com/sb-factors-affecting-germination-of-organic-seeds.htmlhttp://www.highmowingseeds.com/sb-factors-affecting-germination-of-organic-seeds.htmlhttp://forums.gardenweb.com/forums/load/tomato/msg0317254629885.htmlhttp://forums.gardenweb.com/forums/load/tomato/msg0317254629885.htmlhttp://www.thompson-morgan.com/effect-of-lighthttp://www.thompson-morgan.com/effect-of-lighthttp://www.iss.jaxa.jp/http://www.iss.jaxa.jp/http://www.iss.jaxa.jp/http://www.thompson-morgan.com/effect-of-lighthttp://forums.gardenweb.com/forums/load/tomato/msg0317254629885.htmlhttp://www.highmowingseeds.com/sb-factors-affecting-germination-of-organic-seeds.htmlhttp://www.researchgate.net/publication/11803400_Autotropism_automorphogenesis_and_gravityhttp://www.researchgate.net/publication/11803400_Autotropism_automorphogenesis_and_gravityhttp://www.jaxa.jp/article/special/kibo/takahashi_e.htmlhttp://www.kiwispace.org.nz/display/SSAF/Hypothesis+1+-+Automorphogenesishttp://link.springer.com/article/10.1007%2FBF00008074http://www.ncbi.nlm.nih.gov/pubmed/11538807