Bio1b Summer 2008 Eric Harris Plants Lecture 7 Page 1 of 2 PLANTS LECTURE 7 THE PLANT BODY II ROOTS Reading 7th ed 721 723 744 746 756 759 763 767 809 8th ed 747 749 772 773 789 797 841 842 A Roots i Function ii Types of root systems monocot vs dicot iii Regions zone of division differentiation elongation iv Root cap functions gravitropism v Anatomy xylem phloem endodermis pericycle cortex epidermis root hairs vi Lateral roots origin vii Modifications of roots prop storage buttress B Modes of Absorption i Water dissolved nutrients may move through the apoplast in and between cell walls or the symplast through cells Water dissolved nutrients moving through the apoplast is unregulated does not pass through selectively permeable cell membranes One water dissolved nutrients enter the symplast they can move from cell to cell via plasmodesmata ii The casparian strip a waxy gasket forces water entering the vascular tissue to pass through the symplast C Symbionts review i Nodules Nitrogen fixation Symbiotic association with bacteria Updated on 08 01 08 Bio1b Summer 2008 Eric Harris Plants Lecture 7 Page 2 of 2 ii Mycorrhizae recall ectomycorrhizae arbuscular mycorrhizae D Nutrient Uptake i Macronutrients C H O P K N S Ca Mg Required in relatively large amounts ii Micronutrients Cl Fe Mn B Z Cu Ni Mo Required in trace amounts mainly function as cofactors iii Mobile vs Immobile nutrients iv Nutrient deficiency in plants Symptoms Updated on 08 01 08
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