@article{oai:u-ryukyu.repo.nii.ac.jp:02002707, author = {比屋根, 真一 and 川満, 芳信 and 村山, 盛一 and Hiyane, Shinichi and Kawamitsu, Yoshinobu and Murayama, Seiichi}, issue = {45}, journal = {琉球大学農学部学術報告, The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus}, note = {Saccharum officinarumのBadilaと栽培品種であるS.spp.のNiF8を用いて, 葉面飽差の違いがサトウキビの光合成特性に及ぼす影響について検討した。葉面飽差の上昇に対し, 両種共に光合成速度の低下は認められず, 蒸散速度は両種共に直線的に上昇した。気孔伝導度においては葉面飽差の上昇に伴いNiF8では直線的に, Badilaでは25mb付近まで直線的に低下し, その後, 定常値に達した。葉内CO_2濃度は, 葉面飽差の上昇にともない直線的に低下し, 両種間に差はなかった。次に, 葉面飽差が葉内要因に与える影響を検討するため, 異なる葉面飽差下でCi-光合成曲線とその初期勾配である炭素固定効率, および光-光合成曲線の初期勾配である光利用効率を求め検討した。その結果, 高葉面飽差下で炭素固定効率, 光利用効率は低下した。しかし, これらは統計的に有意な差とは言えなかった。葉面飽差が葉の水ポテンシャル, 浸透ポテンシャル及び圧ポテンシャルに与える影響を検討したところ, 葉面飽差が大きく変化したにも関わらず, 各ポテンシャルは変化せず, その値はそれぞれ-0.23,-0.87,0.64MPaであった。, This paper described that the effects of leaf-to-air vapor pressure difference (VPD) on photosynthesis, transpiration, leaf conductance and leaf water potential in Saccharum species (S. ssp. cv. NiF8 and S. officinarum cv. Badila), C_4 plants have been well-known a having strong resistance to VPD as compared with C_3 plants. In addition, we determined the carboxylation efficiency, obtained from the initial slope of the A/Ci curve, and apparent quantum yield, acquired from the initial slope of photosynthetic light response curve at different VPD conditions. The results indicated that there were no changes in photosynthesis and leaf water potential in sugarcane used with increasing VPDs. Transpiration rate was increased linearly with increasing VPD. Leaf conductance and internal CO_2 concentration were decreased with increasing VPD. The carboxylation efficiency and apparent quantum yield were decreased at high VPD, suggesting that photosynthetic activities were damaged at the high evaporation demands. However, there was no statistic significance between VPD treatments. Leaf water potential, osmotic potential and pressure potential were not altered at different VPD. It was suggested that the decreases in leaf conductance at high VPD were attributed to the direct responses of stomata to VPD., 紀要論文}, pages = {1--7}, title = {葉面飽差の違いがサトウキビの光合成特性に及ぼす影響} }