Unit 5 Plants

Kingdom Plante Characteristics of plants: eukaryotic cells gymnosperms Characteristics of plants: eukaryotic cells multi-celluar carry out photosynthesis cell walls contain cellulose develop from embryos protected by tissues of the parent plant angiosperms ferns mosses

Uses of Plants Plants are used by human beings in innumerable ways. Clockwise from top left: coffee beans, sisal plant used to make ropes and mats, rice field, foxglove used to make the heart medicine digitalis, cotton, logging truck for timber or pulp, tomato plant, henna tattoo, rose, tobacco plant, rubber tree

(mosses, liverworts, and hornworts): Non-vascular plants Vascular plants (ferns, gymnosperms [conifers], and angiosperms [flowering plants]): contain conducting tissues to transport materials can grow much taller due to ability to conduct water can reproduce by spores (ferns) or seeds (gymnosperms and angiosperms) ~ 264 000 species (mosses, liverworts, and hornworts): lack true roots, stems, and leaves grow in dense mats in moist environments grow on soil, rock, or dead trees ~ 19 000 species

Angiospermae are a division (or phylum) of plants that produce flowers as part of their reproductive process. These plants vary widely in size and shape but all have a set of distinctive features.

Why Are They So Successful? approximately 250 000 known species all have flowers produce fruit may be fleshy or dry most recently evolved youngest flowers allow for easy gamete transfer ovules are well protected seeds are well protected & nourished variety of seed dispersal methods

MONOCOTS vascular bundles are scattered throughout stem produce one seed leaf flower parts in multiples of three have narrow leaves with parallel veins fibrous root system

DICOTS vascular bundles in a ring pattern in stem two seed leaves flower parts in multiples of four or five broad leaves with branching veins tap root system

Roots anchor plants to ground absorb water and minerals from the soil transport materials upwards to the rest of plant storage of food (e.g. starch) made in stems and leaves Root hairs enormously increase the surface area of a root. The greater the surface area, the more fluid absorption can occur. Shown here are root hairs on the taproot of a sweetcorn plant.

tap roots reach deep into the ground for water (e. g tap roots reach deep into the ground for water (e.g. carrot, dandelion) fibrous roots spread out extensively and help hold the soil in place (e.g. wheat, grasses) adventitious roots help support a plant (e.g. corn, ivy)

epidermis endodermis cortex xylem phloem

Epidermis The outer protective layer of the root Root Hairs Modified epidermis that is the site of water & mineral absorbance A storage layer in the root with large starch-filled cells Cortex Endodermis Minerals must be actively transported to pass through this layer and water follows by osmosis Casparian Strip A waxy substance that prevents water from passing between endodermis cells

Vascular cylindar Xylem Transports water and minerals upwards Transports sugars [with some water] downwards Phloem

Monocot Roots large vascular cylinder in center ring pattern of xylem (large openings) and phloem tissue surrounded by endodermis vascular cylinder surrounded by fairly thick cortex fibrous root system

Dicot Roots small vascular cylinder in center; large openings are xylem tissue surrounded by smaller phloem cells in a ‘star’-shaped pattern very thick cortex tap root system