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No.49 (2002/12) >

 
Title :パインアップルの明期における気孔閉鎖を制御する要因について
Title alternative :On the factors controlling stomatal closure during light period in pineapple
Authors :川満, 芳信
重久, 利枝子
福澤, 康典
村山, 盛一
Authors alternative :Kawamitsu, Yoshinobu
Shigehisa, Rieko
Fukuzawa, Yasunori
Murayama, Seiichi
Issue Date :1-Dec-2002
Abstract :CAM植物であるパインアップルのCO_2収支量を増大させるためには明期の気孔を更に開孔させる必要があると考え,気孔開閉を制限している要因を検討した.1.暗期を短縮してCO_2固定を抑制してもリンゴ酸蓄積量は対照区とほぼ同じであった.暗期におけるリンゴ蓄積量とPhase-3の長さ,明期におけるリンゴ酸の消失と気孔開孔(ガス交換の開始)には関係は無く,Phase-4において葉内CO_2濃度が低下しても気孔は開かなかった.2.暗期短縮やCO_2-free air処理はリンゴ酸蓄積量を減少させたが,Phase-4の気孔開孔は著しく阻害された.3.葉のリンゴ酸含量が増加すると水ポテンシャルおよび浸透ポテンシャルは低下した.4.暗期を短縮した長日条件にすると明期のCO_2吸収は増加し,総CO_2収支量は僅かに増加した.更に明期が長くなると,C_3回路よりもリンゴ酸を精製するC,ジカルボン酸回路が活発に働き,総CO_2収支量の増加は期待できなかった.
In crassulacean acid metabolism (CAM) plants, the CO_2 balance is dependent on the malic acid accumulated in the dark period. Due to the CAM pathways in pineapple, the light use efficiency is low. It is, therefore, necessary to open the stomata further during light period in order to increase the total CO_2 balance. The present paper described that the effects of dark period length and CO_2 free air at Phase 1, stopping the nocturnal CO_3 fixation, on the diurnal changes in gas exchange rate and leaf conductance in pineapple plants. Outlines of the result are as follows ; The malic acid accumulation was almost equal to the control, even if the dark period was shortened. There was no relation between the malic acid accumulation in the dark period and the Phase-3 length and elimination of malic acid and stomatal opening in the light period (e. g. the beginning of the gas exchange at late afternoon). That is to say, the stomatal opening did not occur at Phase 4 even if the low internal CO_2 concentration ocuurred. Dark period shortening and CO_2-free air treatment increased the stomatal conductance in dark period and decreased the malic acid accumulation, resulting the inhibition of stomatal opening at Phase 4. Leaf water potential and osmotic potential decreased when the malic acid content increased. The CO_2 uptake in light period incerased under the long day conditions, however, the totalCO_2 balance slightly increased. If the light period extended more, C_4 cycle which forms the malic acid becomes active in Phase 4 and the increased CO_2 balance could not be expected.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/3616
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.49 p.1 -14
Appears in Collections:No.49 (2002/12)

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