Download Plant Water Absorption and Movement: From Soil to Xylem and more Slides Biology in PDF only on Docsity! • Water is important to plants Plant Environment: Water – Water needed to obtain nutrients from soil (nutrients dissolved in water) – Water critical for plant growth (photosynthesis: 6CO2 + 6H2O ---> C6H12O6 + 6O2) – Water needed for cell elongation, one way plant tissues increase in size – Water makes up 80-90% of herbaceous and 50% of woody plants Docsity.com • How does water move through plants? Plant Environment: Water • Root hairs greatly increase surface area for water entry • Water enters root hairs (projections of cells above root tip) • Root cells ‘pump’ minerals into cells (using ATP energy) – From soil into root cells • High concentration of minerals inside roots creates osmotic gradient (difference in water concentration) – Water moves from high to low water concentration – Adding minerals into roots decreases the concentration of water in roots causing water to enter by osmosis Docsity.com • How does water move through plants? • Water molecules ‘clings’ to xylem and to each other • Water in xylem is unbroken ‘column’ • Water evaporates from leaves ‘pulling’ water up xylem – Evaporative water loss through stomates of leaves is transpiration Plant Environment: Water – From xylem upward to leaves – 90% of water ‘absorbed’ by roots lost via transpiration in leaves Docsity.com • Other uses of water in horticulture – Frost protection – Modify local environment – Irrigation Plant Environment: Water – Cooling turf or greenhouse (by evaporative cooling) Docsity.com • Water deficiency in plants • Reduction in growth • Smaller leaves Plant Environment: Water – Slight water stress causes stomates to close; photosynthesis reduced • Shorter internodes • Smaller plants – Slight water stress can effectively prevent fast, leggy growth Docsity.com • Proper watering of plants • Garden plants need regular water • Deficits followed by excess water during particular growth stages reduces quality of vegetable Plant Environment: Water – garden plants – beans with large air pockets – Ruptures in tomato skin – Growth cracks in carrots Docsity.com • Soluble salt problems: • High levels of salt in soil • High level of salt in irrigation water Plant Environment: Water – Soluble salt problems result from: – Symptoms include: • Wilting • Drying of tips of margins of leaves • Excessive use of fertilizers • Abscission of leaves, flower, fruit (Symptoms same as lack of water…why?) – Problem solved by flushing plant with water Docsity.com
