Studies on Development of the Embryo Sac and Its Abnormality in the Triploid Apple Cultivar ^|^lsquo;Mutsu^|^rsquo;

Abstract

Masashi SATO', Kazumoto KANBE', Shoichi NAKAGAWA2, Ei ji YUDA2 and Shingo FUKU-AGA2 1 Akita Pre ,fectural College of Agriculture, Ogata, Akita 010-04 2 College of .1griccrclture, ('nicer-city of Osaka Prefect ore, Sakai, Osaka 591 Summary To study the process of embryo sac development and its abnormality in a triploid apple cultivar, developing ovules of triploid 'Mutsu' were histologically compared with those of diploid`Goldendiploid`Golden Delicious' in a period from 1 or 2 clays before anthesis through 20 days after cross-pollination. 1. Mature egg apparatuses were found in embryo sacs of`Goldenof`Golden Delicious', whereas they were not observed in 'Mutsu' on the day of anthesis. The percentage of embryo sacs containing a mature egg apparatus of synergids, egg and polar nuclei, and fertilized egg and polar nucleus was 85.4% in 'Mutsu', while it was 98.0% in`Goldenin`Golden Delicious' 3 days after anthesis. 2. The percentage of double-fertilized ovules was about 85-86% in`Mutsuin`Mutsu' and 97-99% in`Goldenin`Golden Delicious'. 3. The percentage of ovules having a non-divided zygote and/or primary endosperm nucleus ,vas as high as 19.4-26.9% in 'Mutsu', whereas it was 1.9-6.2% in`Goldenin`Golden Delicious'. Ovules containing non-divided zygotes and primary endosperm nuclei were most frequently observed in 'Mutsu'. 4. The percentage of ovules having the embryo and/or endosperm degenerated at an early stage of development was 8.9% in`Alutsuin`Alutsu', but 2.5% in`Goldenin`Golden Delicious'. 5. In triploid 'Mutsu' the percentage of ovules lacking fertilization clue to imperfect female gametophytes was about 13%, and that of ovules containing an abnormal embryo and/or endosperm was approximately 28-36%. Such abnormal ones usually showed zygotes and primary endosperm nuclei without nuclear division. •• OE¾ ƒI.•ô ‚ª •':‚± ‚¨1ƒi‚é ƒŠƒ"ƒS‚Ì Žå-v •i Ží ‚Ì ‚¤‚¿,3"{ •« •i Ží`-Ží`-¤ ‰oe'‚ÍŽ÷•¨ ‹-OE' ,'å ‰Ê •«,•‚ •i Ž¿•« ‚È‚Ç‚Ì "Á'¥ ‚ð-L ‚· ‚é ‚à‚Ì ‚Ì,'• Šú-Ž ‰Ê,‚AE ‚-‚ÉJuncdrOp‚AE1OEÄ ‚Î2•Û‚é-Ž ‰Ê:‚ª "N1‚± ‚ae ‚è"¢ ‚µ‚-,'… ‰Ê ‚̈À1‚̈À1'-‚ª "¾‚ª ‚½‚¢ ƒN ‚±,"_ ‚ð-L ‚µ ‚Ä‚¢ ‚é. ƒŠƒ"ƒS3"{ •« •i Ží ‚ɂ‚¢ ‚Ä‚Í,ƒh ƒCƒc‚É‚¨‚¢ƒCƒc‚É‚¨‚¢ ‚Ä‹É‚ß ‚Ä OEà ‚¢ '² •¸ ‚ª ‚ ‚é.‚· ‚È‚í ‚¿,Steillegger(12)‚Í3"{f:L 1987"N6ƒm ƒˆ12"ú Žó-• *OE» •Ý ‹ã •B"OE ŠC'åŠw"_Šw•" •iOEàƒOƒ‰ ƒxƒ" ƒVƒj ƒN ƒCƒ"'(`• ¶-º')‚É ‚‚¢ ‚Äãó‚Ì ‚¤‚Ì "-ˆç ‚É'˜ ‚µ‚¢ˆÙ‚µ‚¢ˆÙ•í ‚Ì ‚ ‚é ‚± ‚AE‚ð"F‚ß,ŠJ ‰Ô Šú‚Ì ãóŽì ‚ª •s Š®'S ‚È‚½‚ßŽó•¸ ‚ð-W ‚° ‚Ä‚¢ ‚é ‚AE •ñ •• ‚µ‚Ä‚¢ ‚é.•c •û,'˜ ŽÒ‚ç‚Í 'O•ñ(10)‚Å3"{ •« •i Ží`-¤ ‰oe'‚Å‚Í,•s Žó•¸ ‚àˆê ‚àˆê •cˆö ‚AE ‚È ‚Á‚Ä‚¢ ‚邪 ,Žó •¸ OEã ‚ÉˆÙ•í ‚ð ‚«‚½‚· ãóŽì ‚ª '˜ ‚µ ‚-.'½‚-,ãó Žì ‚Ì-ñ50%‚ª •‰ Šú"-ˆç ‚Ì 'i ŠK‚Å'Þ ‰» ‚· ‚é ‚± ‚AE ‚𠎦 •´ ‚µ‚½.‚µ ‚©‚µ,ãó ‚Ì ‚¤‚Ì Š®'S"x ‹y‚ÑŽó•¸-¦,Žó •¸-'‚âãó "ûOE´Šj ‚ª •ª-ô ‚µ‚È‚¢ãóŽì,ãó ‚â ãó"û‚ª •‰ Šú"-ˆç ‚Ì ŽžŠú‚ÉˆÙ•í ‚ð ‚«‚½‚· ãóŽì ‚È‚Ç‚Ì Š".• ‡‚ɂ‚¢‚Ä‚Í,‚È ‚¨ •s-¾‚È"_‚ª '½‚¢. 366