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Plants Monocots vs Dicots Seed Monocots have one thin leaf inside the seed coat and it DOES NOT encompass the endosperm Dicots have TWO seed leaves that surround the endosperm and the seeds are usually round and flat Germination Germination produces a single, long and narrow leaf in monocots. It is similar to the shape of the adult leaf. Some may be small and rounded, but there will still only be one Dicots produce two fat seed leaves - fatter than the adult leaves because they contain the nutrition for the new plant Stems and Roots Short and stringy roots with Bulbs (formations from the stem) are present. The stems are fleshy and they do NOT get thicker from one year to the next. Vascular bundles are spread randomly in the stem The root is often a long taproot with smaller (new) roots growing out of it. The stem is tough and grows wider with successive years and the vascular bundles are in a ring Leaves Monocots have long and narrow leaves with parallel veins that run up and down the leaf, or they are parallel from the central vein Dicots have a variety of leaf shape and veination net-like from the central midrib Flowers the organs, (parts) of the flower are in threes. There are usually the same number of stamens as petals The flowers have parts that are in fours or fives and the calyx is usually green Seedpods The seedpods of monocots have three parts and there are large fleshy seeds inside. Seedpods are variable in dicots with a greater number of seeds present than in a monocot Stem Tissues Tissues Vascular - tissues which are conducting, allowing the flow of fluids and nutrients Types are Xylem (water, minerals) and Phloem (sugars) they are arranged in bundles with Cambium in between which will produce new cells of both allowing for the plant to thicken. They transport the fluids and nutrients from the root to the leaf Meristem is undifferentiated cells which give rise to various organs - vascular tissue, flowers, leaves. They are filled with cytoplasm and few organelles In woody plants the vascular bundles are protected by cork cambium between the phloem - the outer cortex breaks through the epidermis - bark! Leaf Tissue Leaf Tissues and functions the photosynthetic organs the upper epidermis is a protective single layer of cells covered in a waxy cuticle to prevent water loss from the upper surface that is exposed to sunlight and heat The mesophyll is in the mid-section and consists of two types of tissue - Pallisade parenchyma and spongy parenchyma Pallisade tightly packed columnar cells with lots of chloroplasts and is the main photosynthetic tissue spongy parenchyma are irregularly shaped and allow the gases to circulate as they enter from the stomata and guard cells on the underside of the leaf Water and minerals are drawn up from the roots through the xylem (dead structure) - vascular tissues, and transpiration occurs through the leaf to the atmosphere while phloem (living cells) transports the sugars back down to all parts of the plant Modifications Bulbs - modified leaf bases food storage scaly leaf bases that encircle the storage center of the bulb modified stem found at the base of the root from which the roots grow new stems and leaves arise from the upper side of the base Stem tubers - modified stems that have food (nutrients) storage in large swollen structures on the stem extensions in the ground Allows for survival of harsh conditions - winter Used for asexual reproduction as new plants grow from these stem tubers Storage roots like carrots, are modified roots that store food and allow the plant to survive adverse conditions Tendrils are modified leaves that are very thin and they extend out and wrap around a solid structure allowing the plants to grow upwards. Grape vines, peas and my favorite flower the sweet pea all have tendrils Meristem Meristem - Totipotent cells These cells have not yet differentiated into specific functions and are found in several places in the plant They allow for the continuous growth of plants and the formation of new organs like roots, branches and leaves Apical Meristems found at the tips of roots and shoots to allow growth of roots in length and stems taller and form leaves and flowers Important to increase anchorage of the plant and get nutrients plus increase photosynthesis closer to the sun and more leaves apical meristems increase is called primary growth Lateral Meristems this is called secondary growth it results in the thickening of the plant, increasing its diameter it results from cell division in the lateral meristems also produces extra xylem and phloem gives the plant stability so it can grow taller Homework http://www.phschool.com/science/biolo gy_place/biocoach/plants/intro.html Complete the activities up and including #6. Print or save your answers to the quiz Tropisms