Breaking Dormancy of Ipil-Ipil Seeds (Leucaenaleucocephala L.) and Storage of Orthodox and Recalcitrant Seeds1
Charles John Gunay
Group 2 Section Y-1L
March 19, 2013
1A scientific paper submitted in partial fulfillment of the requirements in Fundamentals of Crop Science I laboratory under Mr. Arlan James D. Rodeo, 2nd sem., 2012-2013
Seeds are the specialized parts of the plants that results to a new plant. They provide a site of food and shelter for it. Because of the process called germination, matured seeds can be able to sprout. Germinating seeds absorbs great amount of water. This water initiates different chemical processes that will occur inside the seed. This is also the reason why the seeds’ internal tissues swell, causing the seed coat to break. Seeds have a high respiration rate, thus need ample but sufficient amountamount of oxygen. Respiration allows the germinating seed to break down food and convert it to energy essential for growth. Germination varies its complimentary temperature. Though, a lot of seeds want low temperature when it will germinate. In general, germination requires abundant water, ample amount of oxygen and suitable temperature depending on the type of seed (World Book Encyclopedia, 1997).
There are two kinds of germination: hypogeal and epigeal germination. For hypogeal germination, the epicotyl elongates leaving the cotyledon under ground while for epigeal germination, the hypocotyl is the one that gets longer and pushes through the soil (Roberts and King , 1987).
However, there are times when viable seeds fail to germinate even at favorable conditions of moisture and temperature. This is called seed dormancy. Through ages, there are seeds having a hard coat that do not let them absorb water they need for germination. Although, there have been a lot of methods that enables the coats permeable (The Encyclopedia Americana,1976). Some methods used to break dormancy are scarification, temperature treatments, light treatments and treatments with regulators and chemicals. Scarification destroys the hardness of the coat physically or chemically. For temperature treatments, seed can be either be placed to low temperature ( 0 – 5OC), 40 – 50OC or be soaked at 80OC temperate water. Some seeds cannot germinate in the absence of light, thus it should be treated with spontaneous exposition of light. Moreover, for an endogenous dormancy, it must be treated with little amount of growth regulators (My Agricultural Information Bank, 2011).
This study was conducted last February 26, 2013, observed until March 5, 2013 at the University of the Philippines Los Baños, Agronomy Building, Crop Science Cluster Room 138.
The study aimed to determine the germination pattern of dicot and monocot seedling, break dormancy of ipil-ipil seeds (Leucaenaleucocephala L.) and study the storage of orthodox seeds and recalcitrant seeds. The specific objectives were to determine and compare the germination pattern of a dicot and monocot seed corresponding to hypogeal and epigeal germination, determine the efficiency of mechanical scarification- through rubbing on sandpaper and clipping with respect to breaking dormancy of LeucaenaleucocephalaL. seeds, and effect of initial moisture content on the storability of rice seeds and determine the storability of recalcitrant seeds.
In evaluating the germination, dormancy and storage of seeds different procedures were done. In seed germination, a dicot and a monocot seed were chosen to represent seeds exhibiting epigeal and hypogeal germination, respectively. Fifty seeds were germinated in moist filter paper inside a container. For one week, the germination pattern were observed everyday and an illustration of day-to-day observations was then plotted. Roots and shoots length (cm) were also obtained for each day. The average...