菜心小孢子发育时期与花器官形态的相关性

研究菜心小孢子不同发育时期的细胞学特征及其与花器官外部形态的相关性,为直接从花器官外部形态特征来判断小孢子发育时期提供依据。结果表明,菜心小孢子发育分为四分体时期、单核期和双核期,各时期特征明显。菜心小孢子发育时期与花蕾和花药外部形态特征密切相关,供试菜心材料中处在单核靠边期的花蕾纵径为3.05～3.39 mm,花萼长为3.25～3.46 mm,花瓣长为2.10～2.33 mm,瓣萼比为0.63～0.71,花药长为2.57～2.89 mm、瓣药比为0.77～0.85,适合作为不同材料花蕾最佳取样时期的鉴定指标。处在单核靠边期的花器官外观特征表现为花蕾饱满,萼片绿色并包被着花冠,花瓣和花药均为浅黄色,花药略长于花瓣。可见,依据花器官形态特征可判断菜心小孢子的发育时期及所对应的选蕾标准。

葫芦小孢子发育时期与花器形态相关性

为了能够快速准确判断葫芦小孢子发育时期,通过对葫芦花器外观形态与花药显微结构的观察,并将其与小孢子发育时期进行联系。结果显示:葫芦小孢子经过四分体时期、单核期和二核期后发育成成熟花粉粒;在顶芽生长点肉眼可辨别花芽和叶芽的1 d和2 d时,在6.3~6.7 mm的花蕾中,小孢子多处于单核期,此时葫芦花雄蕊的花粉管干瘪较适合花药、小孢子培养;发育到第3 d、4 d时,花粉管较饱满,此时基本为发育成熟的花粉粒。表明可以根据葫芦花蕾的形态、大小及小孢子的发育时期,确定花药、小孢子培养最佳时期所对应的选蕾标准。

白芷小孢子发育时期与花器形态相关性分析

研究3个白芷品系小孢子发育时期与花蕾形态和花药形态的相关性,以期直接从花蕾形态和花药形态判断小孢子的发育时期。采用苯酚品红对白芷小孢子进行染色,对白芷小孢子发育的细胞学以及小孢子不同发育时期与花柄长、花蕾大小、花药直径、花蕾和花药颜色的关系进行研究。白芷小孢子发育经过四分体时期、单核前期、单核中晚期、二核期和三核期共5个时期,各时期特征明显;3个白芷品系小孢子发育时期与花蕾的外部形态和花药颜色密切相关,其中以CX08-2的花柄长、花蕾直径和花药长度最大,其次为B-2,而B-6为最小;但单核中晚期与其相邻时期的花柄长、花蕾直径和花药长度未达到显著水平,花瓣颜色、花瓣是否开裂和花药颜色可以作为花药培养取材的直观依据。通过花器官形态判断小孢子的发育时期可以为白芷花药培养接种材料的选择提供依据。

小白菜小孢子发育与花器官形态相关性

通过DAPI染色观察不同大小的小白菜花蕾内小孢子发育外部形态结构特征及细胞学特征变化,以确定花粉发育时期,找出小孢子发育时期和花外部形态结构相关性,为花药或小孢子培养提供细胞学证据。研究结果表明:小白菜小孢子发育经过二分体时期、四分体时期、单核靠边期、单核居中期、2-胞花粉和3-胞花粉时期,各时期特征明显;且各发育时期与花蕾及花药外部形态密切相关,其中单核靠边期时花蕾纵径为2.68~3.80 mm,横径为1.91~2.19 mm,花药纵径为1.76~2.39 mm,横径为0.64~0.82 mm,花药颜色为浅黄绿色,此时期适合花药、小孢子培养;因此可根据小白菜花蕾形态、大小和小孢子发育时期的相关性,确定花药、小孢子培养最佳时期的选蕾标准。

茎瘤芥甬榨2号小孢子发育时期与花器官形态的相关性分析

对茎瘤芥品种甬榨2号不同发育时期的花药及小孢子进行细胞学观察,明确小孢子发育各时期的细胞结构特征;观察、测定小孢子不同发育时期的花器官形态指标,进而分析小孢子发育时期与花器官形态的相关性。结果表明,甬榨2号小孢子形成经历了小孢子母细胞时期、四分体时期、单核早中期、单核后期、双核时期及三核时期,各时期特征明显,且与花器官外部形态指标具有一定的相关性。单核后期、双核时期的花药和花瓣颜色特征明显,而且双核时期的的花瓣长于花药,由此可肉眼简单区分出甬榨2号小孢子发育的单核后期;小孢子各发育时期的花蕾纵径和花蕾横径均差异显著,且花蕾纵茎测量简单方便,甬榨2号单核后期的花蕾纵径范围为3.50~3.79 mm,可依据此标准进一步确定处在单核后期的花蕾。

Expression and Interaction Analysis of FAZ1 Protein in Brassica oleracea

To identify and characterize genes involved in reproductive tissue abscission in Brassica oleracea,the transcript data of pollinated pistil was analyzed.A differentially expressed gene,named BoFAZ1(FLOWER ABSCISSION ZONE1)was identified,which contains one exon and encompass a 139aa.Furthermore,a T-DNA insertion mutant(SALK_302_G01)(faz1 mutant)was obtained from Arabidopsis thaliana mutant library.Floral organ shedding from mutants was delayed and a V-shaped structure in the boundary region between the stalk and torus of the sepal abscission zone was obtained in faz1 mutant.The cell density of this structure was lower than that of the corresponding region in the wild-type control.In the transgenic plants,the normal development of the stalk zone of faz1 was recovered completely by transforming a 1919-bp DNA fragment of BoFAZ1 into the faz1 mutant.In Addition,our data showed that BoFAZ1 was expressed in mature pollen grains,but not in the bracts,roots,stems,leaves,and sepals.Its expression in the filaments,stigma,and pistil exfoliation layer gradually increased after pollination.Subcellular localization experiments showed that BoFAZ1 was located in the cell membrane.A myristoylation site was found at the N-terminus of BoFAZ1.Removal of this site resulted in protein dislocation in the cytoplasm,cell membrane and nucleus.Finally,a yeast two-hybrid test indicated that BoH3.2(histone H3.2),a protein involved in abscission zone development,interacted with BoFAZ1.This interaction was verified by a GST pull-down assay.In summary,our data indicated that BoFAZ1 was involved in the formation of the pistil abscission zone in B.oleracea.

Cloning and Functional Analysis of the MADS-box CiMADS9 Gene from Carya illinoinensis

A MADS-box gene,CiMADS9,was cloned from the male flowers of Carya illinoinensis by rapid amplification of cDNA ends. The gene was 1 077 bp with a 768 bp open reading frame encoding 255 amino acids. Multiple sequence comparisons revealed that Ci MADS9 is a typical MIKC-type MADS-box gene with a MADS-box domain and a K semi-conserved region. Phylogenetic analysis indicated that CiMADS9 belongs to the AGL15 group of the MADS-box gene family. Quantitative reverse transcription polymerase chain reaction analysis indicated that the expression levels in reproductive organs(i.e.,flowers and young fruits) were considerably higher than in vegetative tissues(i.e.,leaves and branches). The highest expression levels were observed in male flowers. An overexpression vector for CiMADS9 was constructed and the gene was inserted into the Arabidopsis thaliana genome. CiMADS9 expression was confirmed in all transgenic lines. Compared with wild-type plants,transgenic A. thaliana plants overexpressing CiMADS9 exhibited delayed flowering and an increased number of leaves.