Different Factors Affecting the Dormancy of Rottboellia Cochinchinensis

...

A study by Arku et al (2010) on the seed germination ecology of Rottboellia discussed that seedling emergence was greatest for seeds placed on the soil surface and that seedling emergence was greatest at shallow depths. This corresponded to the results of the experiment since generally, the soil was a better medium and the seeds were sown in shallow depths only in the Petri dishes. In field conditions, it is also evident that seeds do not germinate when they are on the deep layer of the soil. When tillage or other land preparation is applied, seeds that are transferred on the shallow part of the soil then germinates.

In comparing the treatments, there is no obvious trend on the germination percentage. In filter paper medium, the best treatment is that exposed to diffused light while the least performing treatment is the one exposed to artificial light in contrast to the result in soil medium wherein the highest percent germination was observed in artificial light. Diffused light and dark treatments had an equal germination percentage.

Another finding on the study on the seed germination and ecology of Rottboellia (Arku et al, 2010) was that germination was stimulated by light. The role of light in germination is quite evident since it is necessary to start the physiological processes of the seed. Since on the results of the experiment, diffused light increased the germination in filter paper medium while artificial light increased germination in soil medium, it can be said that soil is a good medium to improve germination if the light provided to the seeds is generally constant in amount or intensity. In actual condition in the field, seeds do germinate in the presence of light given that the amount is not too much and as much as possible, the exposure is consistent. Dormancy in the field is shorter when light exposure is provided and when the seeds are not in lower depth in the soil.

Based on the results, germination is favored in dehulled seeds and exposure to light as well as soil as medium increases the percent germination of seeds although the results do not really vary significantly, and the trends were not consistent.

CONCLUSION AND RECOMMENDATION

The role of the husk or hull in the dormancy of Rottboellia seed as well as the effect of light and contact with soil and the interaction of these factors on its germination were determined.

Supported by the results, induced or higher germination rate was observed in dehulled seeds due to the breaking of physical dormancy possessed by the itchgrass seeds. The husk or hull keeps the seeds dormant by making the seed unaffected of the presence of germination conditions.

Light and soil contact positively affects the germination but there are certain conditions to be met. Light is a requirement to start germination but too much light will make the temperature high which may induce dormancy. Soil contains nutrients that other medium cannot provide but the depth must be shallow so light can still penetrate and aeration will still be provided.

Light alone or soil alone may increase the germination rate individually, but their interaction will give the best positive result on the germination of Rottboellia seeds. This relationship or interaction is termed as synergy wherein the interaction of two factors have a greater effect than the sum of their separate effects.

It can be recommended in further studies to test the factors with specific variations such as light intensity, soil depth and soil type and varying type of media. It is also recommended to conduct a study simulating real field conditions.

LITERATURE CITED

Arku, G., Chauhan, B., and Johnson, D. (2010). Seed Germination Ecology of Itchgrass

(Rottboellia cochinchinensis). Retrieved October 26, 2017 from

http://www.bioone.org/doi/abs/10.1614/WS-D-10-00095.1

Bhowmik, P. (1997). Weed Biology: Importance to Weed Management. Retrieved October 25,

2017 from

http://www.jstor.org/stable/4046030

Dekker, J. (2011). Evolutionary Ecology of Weeds. Retrieved October 25, 2017 from

http://agron

www.agron.iastate.edu/~weeds/PDF_Library/Agron_517/EEW_ClassUse_1.1.11.pdf

Jantawinyurag, R. (1995). Study on biology and control of itchgrass (Rottboellia

cochinchinensis) and its effect on growth and yield of soybean. Retrieved October 27,

2017 from

http://agris.fao.org/agris-search/search.do?recordID=TH1999001029

Sandoval, J., Rodriguez, P., and Riches, C. (2017). Rottboellia cochinchinensis (itch grass).

Retrieved October 25, 2017 from http://www.cabi.org/isc/datasheet/47782

Thomas, P. and Allision, J. (2009). Seed dormancy and germination in Rottboellia exaltata. Retrieved

October 28, 2017 from https://doi.org/10.1017/S0021859600053491