報告書番号

U89023

タイトル（和文）

植物生体の電気特性測定法（３）－水耕液のｐＨ調整への適用－

タイトル（英文）

CONTINUOUS MEASUREMENT OF ELECTRICAL CHARACTERISTICS IN PLANTS (3) APPLICATION TO HYDROPONIC SOLUTION PH CONTROL

概要 （図表や脚注は「報告書全文」に掲載しております）

栽培環境の適正条件を見極める方法として，非破壊かつ連続測定が可能な植物生体電位測定法の開発，改良を目ざし，接触法の実地適用化に関する実験を行った。この接触法は銀線を電極とし，ペーストにより生体に接着する方法で，インゲンマメ，水稲などの生体電位差を１週間ほどの連続測定ができる。インゲンマメを供試し，その水耕液のｐＨの調整速度について実験し，以下の結果を得た。（１）初生葉と胚軸間の電位差は，水耕液ｐＨの変化によって変化した。（２）水耕液ｐＨの変化速度により電位差の変化量が異なり，０．０２～０．０５ｐＨ／ｍｉｎの場合，ｐＨを急変させた時の１／２～１／４に減少した。（３）吸水量は水耕液ｐＨの急変により，一時的に減少した。（４）以上の結果，水耕液ｐＨを穏やかに調整すれば，生体への影響が少なくなることがうかがえ，適正なｐＨ調節速度をこの電位測定法により求めることが可能と推察された。

概要 （英文）

IN ORDER TO DEVELOP A NON-DESTRUCTIVE CONTINUOUS MEASUREMENT OF PLANT RESPONSES FOR ASSESSING ENVIRONMENTAL CONDITIONS ON PLANTS,BIOELECTRIC POTENTIALS IN INTACT PLANTS WERE MEASURED ANDTHE APPLICABILITY OF A CONTACTSTYLE MEASUREMENT WAS EXAMINED. IMPROVEDELECTRODES WERE USED TO CONTINUOUSLY MEASURE THE ELECTRIC POTENTIAL DIFFERENCE BETWEEN LEAF AND HYPOCOTYL IN BUSH BEAN PLANTS FOR ABOUT SEVENDAYS. THE ELECTRODES,0.3MM SILVER WIRE WERE GLUED ON A PLANT SURFACE WITH GELATIN PASTE THAT WAS PREPARED BY DISSOLVING GELATIN INTO RINGEL SSOLUTION. IN THIS REPORT,THE BIOELECTRIC POTENTIALS AS AN APPLICABLE INDEX DETERMINING FOR AN ADJUSTMENT RATE OF NUTRIENT SOLUTION PH IN HYDROPONICS SYSTEM WERE DISCUSSED. THE RESULTS OBTAINED ARE SUMMARIZED AS FOLLOWS: 1)THE CHANGES OF THE ELECTRIC POTENTIAL BETWEEN THE LEAF AND THE HYPOCOTYL WAS DETECTED WHEN THE PH VALUE OF NUTRIENT SOLUTION WAS ADJUSTED. 2)THE DEGREE OF POTENTIAL CHANGE WAS AFFECTED BY THE ADJUSTMENT RATE OF PH VALUES IN NUTRIENT SOLUTION. THE CHANGE INDUCED BY MIND ADJUSTMENT AT 0.02 0.05 PH/MIN WAS FROM 1/4 TO 1/2 OF THE VIOLENT ADJUSTMENT. 3)WATER ABSORPTION IN BUSH BEAN WAS INHIBITED WITHIN A FEW MINUTES AFTER THE VIOLENT ADJUSTMENT OF PH VALUES. HOWEVER,IT WAS RECOVERED TO THE INITIAL LEVEL AFTER 7 TO 15 MINUTES. 4)THESE RESULTS SUGGEST THAT THE MEASUREMENT OF BIOELECTRIC POTENTIAL IS APPLICABLE TO DETERMINING FORTHE RATE OF PH ADJUSTMENT OF NUTRIENT SOLUTION IN HYDROPONIC SYSTEM. FOR EXAMPLE,IN CASE OF BUSH BEAN,THE PROPER RATE WILL BE 0.02 0.05PH/MIN.

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