Hevjk

• Hay quality


  Determined by stage of harvest
• Leaves lose digestibility as they mature
• Protein content decreases as plants mature
• Digestible components predominate in immature hay
• Stems


  • Transport water, nutrients, sugar
  • Serve as food reserve
  • Provide support and display leaves
  • Undergo some photosynthesis
• Stem propagation


  Stems can form adventitious roots
• Stem structure


  • Woody
  • Internodes
  • Buds (apical and axillary)
• Axillary buds


  • May develop into branches, tillers, or flowering structures
• Parallel veins


  Small and run more or less parallel (mostly monocots)
• Netted veins


  Large and small, small ones connecting to each other to form a network (mostly dicots)
• Pinnately veined


  One larger midvein and smaller veins coming off along its length (mostly dicots)
• Palmately veined


  Two or more large veins arising at or near the base of the leaf blade (mostly dicots)
• Moisture management


  Moisture conserving practices under dryland and irrigation, using efficient practices
• Plants under water stress

  Stomata close, stop CO2 intake
• Planting date


  Early planting of warm season crops, long days, high light availability
• Types of compound leaves

  • Palmately compound
  • Pinnately compound
• Palmately compound


  Lobes or divisions come together and are attached at one place at the base
• Pinnately compound


  Compound leaf with the leaflets on two opposite sides but off of one node
• Leaf venation patterns


  • Monocot - parallel
  • Dicot - net pattern
• Parts of a monocot leaf


  • Node
  • Blade
  • Sheath
  • Stem
  • Collar
  • Auricle
  • Ligule
• Differences between monocot and dicot leaves

  • Monocots - blade-like leaf blade, wrap around stem, no petiole, parallel veins
  • Dicots - petiole, net veins
• Leaf anatomy


  Microscopic view of leaf surface, cross-sectional view of internal leaf anatomy
• Parts of a dicot leaf


  • Node
  • Leaf blade
  • Petiole
  • Veins
• CO2 and H2O


  Absorbed from air through stomata, transported from roots through stems to leaves
• Abscisic acid (ABA)


  Plant hormone that functions in many developmental processes including abscission and bud dormancy, produced in roots in response to decreased soil water potential
• ABA in leaves


  Alters osmotic potential of guard cells, causing them to shrink and stomata to close, reducing transpiration
• Transpiration


  Evaporative loss of water from leaves through stomata, allows for transport of water and minerals
• Photosynthesis


  Stomata must be open to allow CO2 entry, but water vapor can move out
• Stomata


  Open during day, closed at night except when plant wilts to stop excessive water loss
• Functions of leaves


  • Photosynthesis
  • Release of water during transpiration
• Photosynthesis reaction


  Conversion of CO2 and H2O to sugars and O2 using light energy
• Placement of Fertilizer


  Depends on type of fertilizer
• Factors affecting photosynthesis rates

  • Light
  • CO2 supply
  • Water supply
  • Temperature
• Phosphorus (P)


  • Less mobile in soil
• Applying Nitrogen (N)


  Can often be applied on the soil surface
• Grazing and clipping


  Affect carbohydrate reserve storage in specialized stems, require adequate time and leaf area for regrowth
• Applying Phosphorus (P)


  Should be incorporated into the soil or banded with the seed
• Weed control


  Rhizomes and stolons can't be controlled effectively by tillage, require systemic herbicides
• Taproots


  • More critical for fertilizer placement than fibrous roots
• Plant population and spacing


  Control branching, tillering, stem height and strength, prevent etiolation and lodging