Phases of Growth

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Phases of Growth

• Vegetative phase - development of stems, leaves,
  and absorbing roots
• Cell division proteins needed N is important
• Elongation hormones for wall stretching, water,
  cellulose for wall
• Differentiation more carbohydrates for
  secondary thickenings, etc.

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Reproductive Phase

• Development of flower buds, flowers, fruit, and
  seed, or enlargement and maturation of storage
  organs
• Starches and sugars for fruits (photosynthesis
  and translocation needed)
• Bud development hormones needed
• Maturation of tissues

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Balance

• Triggered by environmental conditions different
  plants have different requirements.
• Can be mostly vegetative, mostly reproductive, or
  approximately equal.
• Both phases are active (at least after initial
  vegetative growth) although one phase may be very
  slow.

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Vegetative overbalance

• Abundance of water, light, and mineral nutrients
  (especially N) plus a temperature favoring rapid
  cell division rapid rate of photosynthesis
• Luxurious foliage, but no or few flowers
• Poor cuticle formation plant may be somewhat
  spindly and is succulent and juicy
• Cell walls are thin
• Strengthening tissue poorly developed
• Need large quantities of auxins (hormones) for
  elongation

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Reproductive overbalance

• Large quantities of growth inhibitors needed
• Hormones for stimulation (florigens)
• Lower temperature low nutrient supply low
  water low or moderately low rate of
  photosynthesis
• Woodier plant shorter internodes, cold and heat
  hardy non-succulent smaller leaves with thick
  cuticle conducting tissue well developed
  storage tissue packed
• Since there are fewer leaves and stems, yield is
  low
• Evolutionary protective measure ensures seed
  set before death or dormancy

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Nasturtiums
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Three general types

• Woody
• vegetative early in season -gt reproduction and
  maturation of wood in late season
• Herbaceous 1
• vegetative early and reproductive late
• Herbaceous 2
• both phases equal magnitude

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Effect of Pruning
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Effect of Thinning Fruit