Analysis of Water-use Efficiency of Temperate Evergreen Broad-leaved Trees Using Carbon Isotope Discrimination.

Abstract

To obtain information on the leaf-scale control of the CO2 and H2O exchange of temperate evergreen broad-leaved trees, the ratio of the intercellular and ambient CO2 concentrations (Ci/Ca iso.), which is a time-integrated index of intrinsic water-use efficiency, was determined in a buffer green zone, in Akou, Hyogo Prefecture, Japan, using the natural abundance of 13C (Far quhar et al., 1989). The mean Ci/Ca iso. of mature sunlit leaves on the five trees investigated had small variance, and was simi lar to reported values for several temperate-zone plants. The Ci/Ca iso. of shaded leaves in the lower layer of the crown was larger than that of sunlit leaves in the top layer; this was caused mainly by differences in the amount of radiation. Ci/Ca iso. was smallest in the expanding period. The vertical distribution and seasonal variation of Ci/Ca iso. should be considered when apply ing Ci/Ca iso. as an index to evaluate fluxes over vegetation. Key words: Water-use efficiency, Carbon isotope discrimination, Temperate evergreen broad-leaved tree, Ci/Ca •@•X-Ñ OEQ-Ž •ã ‚É‚¨‚¯‚É‚¨‚¯ ‚éH2O•ECO2ƒt ƒ‰ ƒbƒN ƒX ‚Ì '· Šú•"'è ‚ð•s ‚¤•Û‚É•d-v ‚AE ‚È‚éŽ÷-Ø OEÂ-t ‚É‚ae‚éƒK ƒX OEð Š· • §OEä ‚ÉŠÖ ‚· ‚é•î •ñ ‚ð'ñ ‹Ÿ‚· ‚邱 ‚AE ‚ð-Ú "I‚AE‚µ,•º OEÉ OE § •Ô•äŽs•l •HŽ÷-Ñ 'Ñ‚É• ¶ˆç‚· ‚é5Ží ‚Ì 'g‰· 'Ñ•«•í-Î •L-t Ž÷‚ð'Î •Û‚AE‚µ‚Ä-t‚AE Žü•Ó'å ‹CCO2‚Ì'Y'f ˆÀ'è "¯ˆÊ 'Ì "ä ‚ð'ª 'è ‚µ, Farquhar et al. (1989)‚Ì 'Y'f ˆÀ'è "¯ˆÊ'Ì •ª •Êƒ‚ ƒfƒ‹ ‚ð-p ‚¢‚Ä'· Šú•½‹Ï "I ‚È•×-EŠÔ OE" ‚AE 'å‹C‚ÌCO2"Z"x"ä(Ci/Ca iso.)‚ð ŽZ•o ‚µ‚½.‚» ‚Ì OE‹ ‰Ê,•ã'w•¬•n-t ‚ÌCi/Ca iso.‚ÍŽ÷ Ží ŠÔ •· ‚ª •¬‚³ ‚- ,-l •X‚È‹COEó ‹ae‚É• ¶ˆç‚· ‚éŽ÷-Ø ‚Ì • ¶OE£ 'l ‚AE "äŠr‚· ‚é ‚AE 'g‰· 'Ñ•«‹COEó ‹ae‚É• ¶ˆç ‚· ‚éŽ÷-Ø‚AE ‹ß ‚¢'l ‚Å‚ ‚é ‚±‚AE ‚ª Ž¦ ‚³ ‚ꂽ.‚Ü ‚½,'Î •Û-Ø ‰º 'w-t ‚Í•ã'w-t ‚ae‚è‚àŽóOEõ-Ê ‚ª •¬ ‚³ ‚¢ ‚± ‚AE ‚É‹Nˆö ‚µ‚Ä Ci /Ca iso.‚ª 'å ‚«‚©‚Á‚½.•ã 'w-t ‚ÌCi/Ca iso.‚Í"W ŠJ'¼OEã ‚É•Å •¬'l ‚ð‚AE‚è,‰Ä‚ɕ㕸 ‚· ‚é ‚AE ‚¢ ‚¤‹G•ß •Ï ‰» ‚ðŽ¦ ‚µ‚½.‚µ ‚½‚ª ‚Á ‚Ä,Ž÷-Ñ ‚Ì ƒK ƒX OEð Š·-Ê •"'è ‚Ì ƒpƒ‰ ƒ••[ ƒ^‚AE ‚µ‚ÄCi/Ca iso.‚ð-p ‚¢‚é•Û‚É‚Í,‚» ‚Ì ‹óŠÔ •ª •z‚â‹G•ß•Ï "®‚ð•l-¶ ‚· ‚é•K-v ‚ª ‚ ‚é. ƒL•[ ƒ••[ ƒh:•…-˜-p OEø-¦,'Y 'f ˆÀ'è "¯ˆÊ'Ì •ª •Ê,'g ‰· 'Ñ•«•í-Î •L-t Ž÷, Ci/Ca I.•@ ‚Í ‚ ¶ ‚ß ‚É •@•A•¨ •\ 'å ‹C ŠÔ‚ÌCO2•EH2OOEðŠ· ‰ß 'ö ‚Í •ú ŽË,Ž¼ "x, ‹C ‰·,•-'¬,'å ‹CCO2"Z"x ‚È ‚Ç‚Ì ŠÂ‹«-v 'f ‚É ‚ae‚Á‚Ä ‰e ‹¿ ‚ð Žó‚¯,"¯ Žž‚É‚» ‚ê ‚ç ‚Ì ŠÂ‹«-v 'f ‚ɉe ‹¿ ‚ð-^ ‚¦ ‚Ä‚¢ ‚é.•¡ OEã-\ 'z ‚³ ‚ê ‚é •¢ ŠE‹K-Í ‚Å‚Ì Š‰ •…‚â ‹C ‰·, CO2"Z"x ‚Ì •ã •¸ ‚È ‚Ç‚Ì ‹COEó•Ï "®‚É'Î ‚· ‚é•A• ¶ ‚Ì-ð Š" ‚ð ‰ð-¾‚· ‚é ‚½‚ß ‚É‚Í,•A •¨ •\ 'å ‹C ŠÔ‚Ì ƒKƒXOEð Š· ‰ß 'ö ‚ð •³ Šm‚É"c ˆ¬ ‚· ‚é ‚± ‚AE ‚ª •d-v ‚È‰Û 'è ‚Å‚ ‚é."Á ‚É,-¤ ˆae ‚Ì •A• ¶ ‚Ì ' † ‚Å‚à'å ‚« ‚È-Ê•Ï ‚ð •è ‚ß ‚é •X-Ñ ‚É‚¨‚¯‚É‚¨‚¯ ‚é ƒKƒXOEð Š· ‰ß 'ö ‚Ì ‰e ‹¿-Í‚Í 'å ‚«‚¢ ‚AE •l ‚¦ ‚ç‚ê,‚» ‚Ì 'è-Ê "I •] ‰¿ ‚É'Î ‚· ‚éŽÐ‰ï"I-v ‹• ‚Í •‚ ‚¢.•A •¨ •\ 'å ‹C ŠÔ‚Ì ƒKƒXOEð Š· ‰ß 'ö ‚Í ŠÂ‹«-v 'f ‚AE •A•¨ ‚Ì • ¶-•-v 'f ‚É ‚ae‚Á‚Ä• § OE䂳 ‚ê ‚é.•A •¨ •\ 'å ‹C ŠÔ‚Ì ƒKƒXOEðŠ·-Ê ‚𕸠"x ‚ae ‚-\ 'ª ‚· ‚é ‚½‚ß ‚É‚Í,•A •¨ '¤ ‚Ì • § OEä‚ð-¾‚ç‚©‚É ‚· ‚é•K-v ‚ª ‚ ‚é.‚» ‚Ì ‚È‚©‚Å‚à,ŠÂ ‹« ‚Ì •Ï ‰» ‚É•Å ‚à *‹ž"s 'åŠw 'åŠw ‰@ "_Šw OE¤ ‹ †‰È 'nˆaeŠÂ ‹«‰È Šw •ê •U•@ •X-Ñ •… • ¶Šw •ª-ì•@• §606-8502•@ ‹ž"sŽs• ¶‹ž ‹ae-k"'•ì 'Ç•ª '¬