Pollen In Plants Lab Report

Lab Report 4

Student No. : 15151131

Introduction

This experiment is to examine the structure of a flower and the transport of water. This experiment should help us to understand why flowers are shaped the way they are, why they have external structures and bright colours. The processes by which water is transported against the force of gravity. Pollen will be extracted from the anther and from the cone structure of pine and spruce trees and examined under different lenses of the microscope. A discussion will be included in this report to describe in more detail how water is transported, the position of the sexual organs on the flower and the reason for pollen in plants. Also, a results section and conclusion will complete the report.

Method

Examples : fibrous roots, the gripping roots of ivy and roots of onion. Upward movement of water through the xylem.

Two processes combine to move water from the roots up to the upper parts of plants: Root pressure and transpiration.

1.) Root pressure: when roots absorb water a pressure is made which helps push water up through xylem vessels. 2.) Transpiration: is the loss of water vapour by evaporation from the surface of the plant.

The COHESION-TENSION MODEL of xylem transport (Dixon and Jolly)

This model depicts how water moves up through a plant against the force of gravity.

Water evaporates from the cells of the leaf by transpiration. These cells become less turgid. (Less swollen)

This causes water to be drawn out from xylem vessels to move into the leaf cells by osmosis.

Water molecules are attracted/ stick to each other (Cohesion) and this cohesive property means that a column of water can move up xylem without breaking.

As transpiration continues it causes a continuous column of water to be pulled up the xylem vessels to replace it- water in the xylem is under tension (stems

"Transpiration is the process where plants absorb water through the roots and then give off water vapor through pores in their leaves. An example of transpiration is when a plant absorbs water in its roots." Plants have several ways of controlling the amount of water they lose from the leaves.

Presence of a cuticle - A cuticle is a waxy layer on the upper surface of leaves ( water cannot pass through it). It prevents the loss of too much water from the plant.

Stomata are located on lower surface of the leaf – not direct sunlight/ cooler, helps reduce water loss.

Opening and closing of stomata – Stoma are tiny pores on the surface of a leaf, through which water vapor escapes.

Stomata open in daylight – transportation occurs

Stomata close at night – no transpiration There are environmental conditions that cause the closing of the stomata because the rate of transpiration may be too high due to high temperatures, high wind, or drought. Reproductive Structures of a Flowering Plant.

Sexual reproduction is the fusion of two gametes to form a diploid zygote.

Stamen

Filament – thin stalk, contains vascular bundles

Anther – produce pollen grains

Carpel

Stigma – where pollen