Photosynthetic light and CO₂ utilization and C₄ traits of two novel super-rice hybrids

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• 作者：Qiang Wang ; Qide Zhang ; Dayong Fan ; Congming Lu
• 关键词：C₄ pathway ; Oryza sativa ; Photosynthesis ; Super-rice hybrids
• 刊名：Journal of Plant Physiology
• 出版年：2006
• 出版时间：3 March 2006
• 年：2006
• 卷：163
• 期：5
• 页码：529-537
• 全文大小：262 K

文摘

Characteristics of photosynthetic light and CO₂ use efficiency from seedling to heading stage, and C₄ pathway enzyme activities in both flag leaves and lemma were compared between two newly developed super-rice hybrids (Oryza sativa L.), Liangyoupeijiu and Hua-an 3, and a traditional rice hybrid, Shanyou 63. At seedling and tillering stages, Liangyoupeijiu and Hua-an 3 had higher net photosynthetic rates (Pn) and light saturated assimilation rates (Asat) than did Shanyou 63, at both normal (360 μmol mol⁻¹) and doubled (720 μmol mol⁻¹) CO₂ concentrations. At the heading stage, the flag leaves of all three rice hybrids had similar Pn and Asat. However, the two super-rice hybrids had higher apparent quantum yield (AQY) and carboxylation efficiency (CE) during all three typical developmental stages, and higher quantum yield of CO₂ fixation (ΦCO₂) at the tillering and heading stages. In addition, Liangyoupeijiu showed significantly higher activities of the C₄ pathway enzymes in both flag leaves and lemmas than did Shanyou 63. As a result, flag leaves of the two super-rice hybrids had higher Pn at morning, noontime and late afternoon during the daily cycle. Since most of the grain yield of rice comes from the photosynthesis of flag leaves, the similar Asat and much higher AQY, CE and ΦCO₂ at heading stage of the two super-rice hybrids indicates that higher photosynthetic efficiency rather than higher photosynthetic capacity may be the primary factor contributing to their higher grain yields.