title: Shoot development and extension of Quercus serrata saplings in response to insect damage and nutrient conditions.
abstract: OBJECTIVE
  Plants have the ability to compensate for damage caused by herbivores. This is important to plant growth, because a plant cannot always avoid damage, even if it has developed defence mechanisms against herbivores. In previous work, we elucidated the herbivory-induced compensatory response of Quercus (at both the individual shoot and whole sapling levels) in both low- and high-nutrient conditions throughout one growing season. In this study, we determine how the compensatory growth of Quercus serrata saplings is achieved at different nutrient levels.
  
  
  METHODS
  Quercus serrata saplings were grown under controlled conditions. Length, number of leaves and percentage of leaf area lost on all extension units (EUs) were measured.
  
  
  RESULTS
  Both the probability of flushing and the length of subsequent EUs significantly increased with an increase in the length of the parent EU. The probability of flushing increased with an increase in leaf damage of the parent EU, but the length of subsequent EUs decreased. This indicates that EU growth is fundamentally regulated at the individual EU level. The probabilities of a second and third flush were significantly higher in plants in high-nutrient soil than those in low-nutrient soil. The subsequent EUs of damaged saplings were also significantly longer at high-nutrient conditions.
  
  
  CONCLUSIONS
  An increase in the probability of flushes in response to herbivore damage is important for damaged saplings to produce new EUs; further, shortening the length of EUs helps to effectively reproduce foliage lost by herbivory. The probability of flushing also varied according to soil nutrient levels, suggesting that the compensatory growth of individual EUs in response to local damage levels is affected by the nutrients available to the whole sapling.
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502 Japan. mizumati@kais.kyoto-u.ac.jp
authors.forename: Eri
authors.initials: E
authors.lastname: Mizumachi
authors.forename: Akira
authors.initials: A
authors.lastname: Mori
authors.forename: Naoya
authors.initials: N
authors.lastname: Osawa
authors.forename: Reiko
authors.initials: R
authors.lastname: Akiyama
authors.forename: Naoko
authors.initials: N
authors.lastname: Tokuchi
mesh_terms: D000818:Animals; D007313:Insecta / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D018520:Plant Shoots / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D029963:Quercus / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D012044:Regression Analysis; D012987:Soil
chemical_list: D012987:Soil; D010758:Phosphorus; D009584:Nitrogen; D011188:Potassium