Morphology, Polyembryony and Germination free essay sample

The main idea of the exercise is being familiarize with the seed and seed germination of some species. In this exercise, the students used seeds of various fruits and vegetables and allowed them to germinate. For the first part of the exercise, all the species used exhibited polyembryony. For the second part, Okra showed epigeal germination while on the other hand corn and papaya both exhibited hypogeal germination. The seed, consisting of an embryo, endosperm, and seed coat, is botanically defined as a ripened ovule. Its embryo is produced sexually through the fusion of the egg and sperm cell or asexually through apomixes when embryo develops from the egg cell without fertilization. Apomixes results to plant with the same genotype thus eliminating variability. The endosperm is the food storage tissue of the seed which is a triploid. Two thirds of it comes from the maternal parent while the remaining one third is form the paternal parent. We will write a custom essay sample on Morphology, Polyembryony and Germination or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page The perisperm and cotyledon are both diploids. However, Perisperm is maternal while cotyledon is equally derived from the maternal and paternal parents. Usually, producing a viable seed requires both pollination and fertilization. But in some instances, there is parthenocarpy or development of the fruit without pollination fertilization, embryo abortion or death during development, or non-filling due to the failure to accumulate required food reserves. All these may lead to development of ‘seedless fruits’. Seed germination is defined as the resumption of active growth of the embryo. During this process, the seed imbibes water, enzymes are activated, growth of embryo is initiated resulting in the rupture of the seed coat and the emergence of the young plant, and finally the establishment of a seedling. Development of the seedlings roots and shoots if important for its successful establishment in the field. OBJECTIVES At the end of the exercise the student should be able to: a) Closely examine and identify the structures of the seed of various species b) Observe seed germination characteristics amp; seedling structures in some species; and c) Describe polyembryonic and monoembryonic seeds. The class was divided into two groups. One group worked on the experiment on Polyembryony while the other worked on the seedling and seedling structure experiment. For polyembryony, ten seeds each of calamansi, mandarin, katchamita, and carabao mangoes, and thirty seeds of lanzones were obtained, cleaned, and allowed to germinate. The number of days to initial germination was noted and seeds were identified as polyembryonic or not. The seeds were observed for a period of four weeks and the number of days to final germination and percent germination were also noted as seen in Table 1. For Seed germination and seedling structure, on the other hand, thirty seeds each of pole sitao, okra, and corn were obtained, cleaned, and germinated. They were observed for a period of four weeks as well and number of days to initial and final germination and percent germination were noted. The type of germination, whether epigeal or hypogeal, was also determined for each.