報告書番号

U90054

タイトル（和文）

組織培養による種苗大量増殖技術の開発（３）－－液体培養におけるイチゴカルスの増殖と培地のｐＨ変化－－

タイトル（英文）

DEVELOPMENT OF TECHNOLOGY FOR PLANTLET PROPAGATION BY TISSUE CULTURE (3) --STRAWBERRY CALLUS GROWTH AND PH CHANGES IN LIQUID MEDIUM--

概要 （図表や脚注は「報告書全文」に掲載しております）

省力化した種苗大量増殖技術の開発のために重要な技術である液体培養法において，カルスの増殖と培地のｐＨ変化について以下の知見を得た。（１）当所で誘導したイチゴカルスは約４週間で約２０倍に増殖すること，（２）組織培養において一般的に用いられる培養条件（培地の組成，ｐＨ，温度など）で培養する限り，ｐＨの変化は４．３～７．０の範囲に納まっていると，（３）ｐＨ４．０～７．０のかなり幅の広い範囲の初期調整ｐＨに適応する能力を持っており，この範囲ではほとんど最大増殖量に差が無いこと，（４）培地ｐＨの変化は加熱滅菌処理や光照射による培地成分（主にＦｅ，ｐ）の沈澱，カルスの増殖にともなう培地成分（ＮＯ３－，ＮＨ４＋）の吸収，代謝産物（ｔ－アコニット酸などの有機酸類）の放出によることが明らかとなった。以上のことからカルス自身が能動的にｐＨの変化を行なっている可能性が認められ，カルスの増殖に関する限り，厳密な

概要 （英文）

LIQUID CULTURE IS AN IMPORTANT TECHNIQUE FORMASS PROPAGATION OF SEEDLINGS. CONSEQUENTLY,A METHOD FOR STRICTLY CONTROLLING THE CULTURE ENVIRONMENT,SUCH AS THE MEDIUM PH,TEMPERATURE,AND OSMOTIC PRESSURE MUST BE DEVELOPED. IN THIS REPORT,WE INVESTIGATE THE EFFECT OF PH ON THE GROWTH OF CALLUSES DERIVED FROM THE STRAWBERRY (FRAGARIA ANANASSA CV. HOKO-WASE) MERISTEM IN LIQUID MEDIUM. WE ALSO INVESTIGATED WHAT CAUSES PH CHANGES. THE MAIN RESULTS ARE LISTED BELOW. (1) CALLUS GROWTH IN LIQUID MEDIUM WHEN THE CALLUS WAS INOCULATED AT A 2% VOLUME OF THE LSII LIQUID MEDIUM (LINSMAIER & SKOOG,1965),THE VOLUME OF THECALLUS WAS INCREASED ABOUT 20 TIMES AFTER FOUR WEEKS. (2) PH CHANGES IN CALLUS CULTURE THE INITIAL PH WAS ADJUSTED TO 6.0 BEFORE AUTOCLAVING.IT DECREASED TO ABOUT 5.5 AFTER AUTOCLAVING AND THEN DECREASED FURTHERTO ABOUT 4.3. HOWEVER,IT INCREASED TO ABOUT 7.0 DURING CALLUS CULTIVATION. (3) EFFECT OF INITIAL PH ON CALLUS GROWTH THE INITIAL PH WAS ADJUSTED TO 3.0 BEFORE AUTOCLAVING:IT INDUCED NO CALLUS GROWTH. BUT WHEN IT WAS ADJUSTED TO BETWEEN 4.0 AND 8.0, IT DID NOT AFFECT CALLUS GROWTH. THE FINAL PH ENDED BETWEEN 6.0 AND 7.0 AFTER THE LOGARITHMIC GROWTH PHASE IN EVERY MEDIUM,EXCEPT IN THE MEDIUM WITH AN INITIAL PH OF 3.0. (4) FACTORS CAUSING PH CHANGES THE FACTORS CAUSING PH CHANGES ARE: 1. PRECIPITATION OF FE AND P WAS INDUCED BY AUTOCLAVING AND/OR LIGHTING DURING STERILIZATION, PRESERVATION AND CULTIVATION, 2. SECRETION OF TWO TYPES OF ORGANIC ACIDS OCCURRED IN THE STATIONARY PHASE OF CALLUS GROWTH. ONE WAS T-ACONIT ACID,BUT THE OTHER IS NOT YETKNOW. 3. THERE WAS A DIFFERENCE IN ABSORPTION BETWEEN NITRATE AMMONIUM NITROGEN IN THE LOGARITHMIC PHASE OF CALLUS GROWTH. THESE RESULTS INDICATE THAT STRAWBERRY CALLUS CAN CONTROL THE SURROUNDING PH UNDER NORMAL CULTURE CONDITIONS. WE MAY NOT HAVE TO DEVELOP A METHOD FOR CONTROLLING PH IF THE PURPOSE IS ONLY CALLUS GROWTH.

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