AG+3321+Lecture+4

AG+3321+Lecture+4 - Range Plant Phys., Range Ecology &...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 5 February 25, 2008 Reading List Exam II Chapter Five – Range Plant Physiology Chapter Six – Range Ecology Chapter Eight – Considerations Concerning Stocking Rate How do Range Managers Control Grazing? Grazing intensity Determines the amount of leaf area left for photosynthesis Timing Season Frequency Time between grazing and recovery Selectivity Palatability of plants, animal type Carbohydrate Reserves Two types of plant carbohydrate Structural carbohydrate (complex CHO) Cellulose, hemicellulose, lignin Not utilized by the plant for other metabolic processes, simply utilized to provide structure to plant Nonstructural carbohydrate (simple CHO) Simple sugars (glucose, fructose), starch Available to the plant thru translocation, utilized for growth, root development, respiration, etc. Seasonal Variation in Growth Warm season grasses New growth stage begins in spring Nonstructural CHO content decreases Reserves are used to develop leaves, stems Depletion of reserves continues until sufficient leaf area is available to replenish reserves through photosynthesis Seasonal Variation in Growth Warm season grasses Full leaf development (4 or 5 th leaf stage) occurs in summer Replenishment of reserves Reserves continue to increase until maximum is reached during reproductive part development Reserves may be depleted, slightly as reproductive parts are formed
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Seasonal Variation in Growth Warm season grasses Dormant stage occurs in fall or winter Depletion of reserves acquired during spring/summer Respiration accounts for vast majority of plant carbohydrate utilization Plant Morphology Phytomer Basic unit of grass plants Consists of: Leaf (sheath and blade) Node Axillary bud Internode Grass Phytomer Plant Morphology Shoot Above ground portion Consists of: Stem Leaf Culmless vs. Culmed Plant Morphology Stolon Lateral shoots growing along the ground Rhizome Under ground stem Both Stolons and Rhizomes can form roots and shoots at nodes (vegetative reproduction) Asexual Propagation Grazing Resistance Ability of plants to survive in grazing systems Two basic systems Avoidance mechanisms Reduce the amount of leaf/plant material removed during grazing Tolerance mechanisms Increase growth rate following grazing to offset losses due to herbivory Grazing Resistance Factors that increase grazing resistance Growth form Reproductive Strategy Reserve carbohydrate location Palatability
Background image of page 2
External morphology The inability of humans to directly derive caloric value from the 19 billion metric tons of vegetation produced annually in tropical and temperate grasslands and savannas (24 million km 2 ) provides the ultimate justification for evaluating grazing as an ecological
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/15/2008 for the course AG 3321 taught by Professor Pollard during the Spring '08 term at Texas State.

Page1 / 9

AG+3321+Lecture+4 - Range Plant Phys., Range Ecology &...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online