Water-use efficiency and carbon isotope discrimination in two cultivars of upland rice during different developmental stages under three water regimes

Bingzi Zhao, Motohiko Kondo, Morihiro Maeda, Yasuo Ozaki, Jiabao Zhang

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

A pot experiment was conducted in a glasshouse to clarify and quantify the effect of plant part, water regime, growth period, and cultivar on carbon isotope discrimination (CID), and to analyze the relationship between CID, stomatal behavior and water-use efficiency (WUE). The experiment was comprised of two upland rice (Oryza sativa L.) cultivars and three water regimes (100, 70, and 40% of saturation moisture) in a completely randomized design. Plants were harvested at tillering, flowering, and maturity. No significant cultivar differences in above-ground dry matter-based WUE (WUE A) and total dry matter-based WUE (WUE T) were observed. WUE A (and WUE T) increased with water stress up to tillering, but decreased with water stress after tillering. Significant cultivar differences in CID in all the analyzed plant parts were observed at all harvest times. Reduction in CID with water stress was greatest at tillering, and the effect was less pronounced at flowering and at maturity. At each harvest, the effect was most pronounced in newly developed plant parts. Root and grain tended to have the lowest CID values, and stem the highest, at all harvest times. A negative relationship was observed between CID measured at tillering and WUE A (and WUE T) measured over the period from seedling to tillering, whereas a reverse relationship was obtained between CID measured at flowering and WUE A (and WUE T) measured over the period from tillering to flowering, and an unclear relationship between CID measured at maturity and WUE A (and WUE T) measured over the period from flowering to maturity. The ratio of the intercellular and atmospheric concentration of CO 2 (C i/C a) were closely associated with CID throughout the water regimes when one cultivar was considered, however, cultivar differences in CID were not related to variations in C i/C a. The results indicate that significant cultivar difference existed in CID in all the analyzed plant parts at all harvest times, while corresponding difference in WUE A (and WUE T) between the cultivars was not necessarily consistent.

Original languageEnglish
Pages (from-to)61-75
Number of pages15
JournalPlant and Soil
Volume261
Issue number1-2
DOIs
Publication statusPublished - Apr 1 2004
Externally publishedYes

Keywords

  • carbon isotope discrimination
  • plant parts
  • upland rice
  • water regimes
  • water-use efficiency

ASJC Scopus subject areas

  • Soil Science
  • Plant Science

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