小麥和玉米穎果的生長及胚乳細(xì)胞的發(fā)育.pdf

1、荊彥平小麥和玉米穎果的生長及胚乳細(xì)胞的發(fā)育小麥和玉米穎果的生長及胚乳細(xì)胞的發(fā)育(揚州大學(xué)生物科學(xué)與技術(shù)學(xué)院，江蘇揚州，225009)研究生：荊彥平導(dǎo)師：王忠(教授)摘要為了探明小麥和玉米穎果的生長及胚乳細(xì)胞的發(fā)育，本研究以小麥(鄭麥9023和揚麥19)，玉米(農(nóng)樂988和揚糯1號)穎果為材料，精確標(biāo)記開花天數(shù)，觀測穎果生長；采用組織化學(xué)染色方法檢測胚乳活性及淀粉含量：采用樹脂包埋制作切片，利用光學(xué)和掃描電子顯微鏡觀察胚乳細(xì)胞及淀粉體的形

2、態(tài)結(jié)構(gòu)變化，結(jié)果如下：1小麥穎果生長及胚乳的發(fā)育(1)小麥穎果發(fā)育前、中期果皮富含葉綠體，呈綠色，穎果成熟后果皮葉綠體解體，果皮由綠色轉(zhuǎn)變成黃白色。穎果長、寬和厚度以及鮮、干重的變化呈“S”型生長曲線，穎果長、寬和厚度在花后16d基本穩(wěn)定，鮮、干重增長在24d以后變緩。穎果發(fā)育前期含水率在70％～80％之間，發(fā)育后期含水率較低。兩種小麥穎果大小，重量，含水率表現(xiàn)為鄭麥9023揚麥19。(2)小麥胚乳細(xì)胞的建成包括游離核和細(xì)胞化兩個時期，

3、鄭麥9023花后O～2d為游離核期，3～4d為細(xì)胞化期，而揚麥19花后O~4d為游離核期，5～6d為細(xì)胞化期。內(nèi)胚乳細(xì)胞的生長呈“S”型曲線，花后16～20d細(xì)胞生長最快。內(nèi)胚乳細(xì)胞呈不規(guī)則多面體形，細(xì)胞內(nèi)含大、小兩種淀粉體，大淀粉體呈橢球形或鵝卵石形，小淀粉體呈圓球形。大淀粉體的增殖和生長主要在花后4～16d進(jìn)行；小淀粉體在花后16d大量出現(xiàn)，隨后數(shù)量逐漸增多，至胚乳發(fā)育后期，小淀粉體數(shù)量占內(nèi)胚乳細(xì)胞淀粉體總量的90％以上。兩種小麥內(nèi)

4、胚乳細(xì)胞大小，內(nèi)胚乳細(xì)胞中大、小淀粉體數(shù)量表現(xiàn)為鄭麥9023揚麥19。(3)小麥穎果中由主維管束運來的養(yǎng)分卸至胚乳腔中，大部分養(yǎng)分通過胚乳傳遞細(xì)胞直接進(jìn)入腹部內(nèi)胚乳細(xì)胞；少部分養(yǎng)分沿種皮質(zhì)外體空間運輸，經(jīng)糊粉層運輸至內(nèi)胚乳。穎果腹部和背部養(yǎng)分運輸距離短，營養(yǎng)優(yōu)先供應(yīng)，內(nèi)胚乳充實程度高，而穎果中部的養(yǎng)分運輸距離較長，營養(yǎng)供應(yīng)較遲，內(nèi)胚乳充實度較低。2玉米穎果生長及胚乳的發(fā)育荊彥平小麥和玉米穎果的生長及胚乳細(xì)胞的發(fā)育TheCaryopsis

5、GrowthandtheEndospermCellDevelopmentinWheatandMaizeAbstractTomakeclearthegrowthofthecaryopsisandthedevelopmentofendospermcellinwheatandmaize，thecaryopsesoftwowheatcultivars，Zhengmai9023andYangmai19，andtwomaizecultivars，N

6、ongle988andYangnu01，wereusedasmaterialsinthisstudyThecaryopsesdevelopmentsdayswerecarefullyrecordedtoobservethecaryopsesgrowthThehistochemicalstainingmethodswereusedtodetecttheactivityofendospermandthecontentofstarchThem

7、orphologyandstructurechangesofendospermcellandamyloplastswereobservedbyusingresinsemithinsectionsandcombinedwithlightmicroscopeandscanningelectronmicroscopeTheresultswere】fistedasbelow1Thecaryopsesgrowthandendospermcelld

8、evelopmentinwheat(1)ThepericarpofwheatcaryopsiswasabundantwithchloroplastsatearlyandmiddledevelopmentstagewhichappearedgreenThechloroplastsdisappearedatlaterstageandthepericarpchangedfromgreentoyellowishwhiteThechangesof

9、lengthwidth，thickness，fleshweightanddryweightofcaryopsispresentScurveThelength，widthandthicknessofcaryopsiswerebasicallystabledat16dayafterfloweringTheincreasingrateoffreshweightanddryweightsloweddownafter24dayThemoistur

10、econtentofcaryopsiswasbetween70％～80％atearlydevelopmentstagewhileinlowercontentatlaterstageThesize，weightandmoisturecontentofcaryopsisintwowheatcultivarswereZhengmai9023Yangmai19(2)Themorphogenesisprocessofendosperminclud

11、edthefreenucleistageandthecellularizationstageThefreenucleistageofZhengmai9023occuredat02dayafterflowering，andthecellularizationstageoccuredat34dayafterfloweringwhilethefreenucleistageofYangmai19occuredat04dayafterflower

12、ing，andthecellularizationstageoccuredat56dayafterfloweringThegrowthofstarchendospermcellpresentedScurveandthefastestgrowthrateoccurredbetween1620dafterfloweringThestarchendospermcellwaspolyhedronshapedandthereweretwokind