Response of Leaf Water Potential of Rice (Orvza sativa L.) to Evaporative Demand under Paddv Field Conditions

Tohru Kobata, Kenji Shiono, Toshiaki Takei, Atushi Katube, Shinichiro Utaka, Tadashi Imaki

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We observed previously (Part 1) that maintenance ability of leaf water potential (Ψ1) in rice plants under paddy field conditions changed depending on planting years and seasons and individual locations, when maintenance ability was calculated by the slope (S) of a regression line between Ψ1 and evaporation rate (E0) measured with a wet filiter paper7 Our objective was to establish whether there is a relationship between grain yield and S for the cultivar Nipponbare grown in a three-year experiment conducted at two locations. Maximum grain yield was 695 g/m2 and lowest yield was 436 g/m2. Efficiency of radiation energy use for grain yield (UEG-indicated by the ratio of grain yield to accumulated short wave radiation, or to hours of sunshine) both during the whole growing season and the grain filling period, were different for each year, season and location. When a mean value of S for 60 days (from–30 to 30 days after heading, 3) was calculated as an indicator of the maintenance ability of Ψ1 at a dominant period of yield determination, there were close relationships between UEG and S. The maintenance ability of Ψ1 during spikelet initiation (from –30 to 0 days after heading) seemed to contribute significantly to high UEG. This conclusion can be drawn firstly because the grain yield was limited by the number of spikelets which had been initiated since 30 days before heading, and secondly because spikelet number appeared to be affected by S during the spikelet formation stage. It may be possible to use S at the mid grain filling period (S20) as an indicator of the magnitude of UEG, since S20 was shown to have a dominant effect on S.Our data suggest that rice which has a greater ability to maintain high Ψ1 for most of the season under wet soil conditions is capable of efficient use of solar radiation in the production of grain.

Original languageEnglish
Pages (from-to)17-26
Number of pages10
JournalJapanese Journal of Crop Science
Issue number1
Publication statusPublished - 1993


  • Evaporative demand
  • Grain yield
  • Leaf water potential
  • Location
  • Radiation
  • Spikelet number

ASJC Scopus subject areas

  • Food Science
  • Agronomy and Crop Science
  • Genetics


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