Lab Work 10 .docx

Lab Work 1 EXTERNAL MORPHOLOGY

Table 1. Fruit and Seed Classification based on Food Storage PLANT Lima bean Mung bean Castor bean Corn Coconut

CLASSIFICATION Exalbuminous Exalbuminous Hypocotylospermous Albuminous Albuminous

Table 2. Fruit and Seed Dispersal PLANT SPECIES

NATURAL DISPERSING AGENT

Pterocarpus/ Triplaris

Insects

Imperata

Wind

Tridax

Wind

Ageratum

Wind and Animals

Impatiens

Explosive seed dispersal/ Selfdispersion

Psidium

Human and Animals

Carica papaya Manilkara zapota Tecoma Bixa orellana Urena

Human and Animals Animals Wind Animal and Wind Animals

Desmodium

Human and Animals

Crotolaria

Explosive seed dispersal/ Selfdispersion and Insects

Terminalia catappa

Water

Lycopersicon esculentum

Human and Animals

STRUCTURAL MODIFICATION (IF PRESENT) Forming myrmecophytes by specialized structures such as domatia, food bodies and extrafloral nectaries. Hairy and wing-like appendages Pappus which is like a parachute that is persistent in the calyx into hairs Sticky hairs on the bracts Explosive dehiscence and has a stored mechanical energy in its fruit tissues The outer pericarp has bright colors and distinct odors None None Flutterer/spinners None Hook-like structures The seeds are adapted with little barbs allowing it to be stuck on the fur or clothing of people Explosive dehiscence and has a stored mechanical energy in its fruit tissues and it contains nectaries Seeds are bouyant The outer pericarp has bright colors and distinct odors

ANSWERS TO QUESTIONS 1. Why did larger seeds evolve? How are these seeds dispersed? Larger seeds evolve in a manner that is driven by climate and environmental changes wherein closed forest vegetation favored larger seed sizes which are dispersed by the animals and water. (Moles, Angela & Ackerly, David & O Webb, Campbell & Tweddle, John & Dickie, John & Westoby, Mark., 2005). 2. Differentiate two types of seed based on endosperm type ; seed germination type and give an example for each. An endosperm is a significant structure of the fertilized embryo which serves as the primary storage tissue, provides starch and other nutrients to the growing embryo. There are two types of seeds based on their utilization of their endosperm. The first one is the albuminous seed wherein the endosperm provides nutrition to the developing embryo but remain even during the germination of the seed and it can be categorized to have an epigeal germination where the cotyledons are brought above the ground due to the elongation of the hypocotyl. Castor seed belongs to this type of germination and endosperm. Meanwhile, the exalbuminous seed uses the endosperms completely hence, their endosperm is completely absorbed during maturity making the cotyledon as their food storage and it has an hypogeal germination where the cotyledons remain in the soil due to the elongation of the epicotyl. This type of germination and endosperm can be seen in the seeds of pea. (Endosperm Development: Development Process, Types, Videos, Example.,2018; Britannica, T. E., 2018)

REFERENCES Britannica,

T. E. (2018, April 11). Endosperm. Retrieved https://www.britannica.com/science/endosperm

March

18,

2019,

from

Endosperm Development: Development Process, Types, Videos, Example. (2018, March 08). Retrieved March 18, 2019, from https://www.toppr.com/guides/biology/sexualreproduction-in-flowering-plants/endosperm-development/ Moles, Angela & Ackerly, David & O Webb, Campbell & Tweddle, John & Dickie, John & Westoby, Mark. (2005). A Brief History of Seed Size. Science (New York, N.Y.). 307. 576-80. 10.1126/science.1104863.