Cytokinin Changes in Embryo and Endosperm of Cassia fistula during Fruit Growth.
TL;DR: The high cytokinin activity in the endosperm at early stages indicates that it may act as a supplier of cytokinins to the embryo during these periods, and the possible significance of these findings is discussed.
About: This article is published in Journal of Plant Physiology.The article was published on 1984-11-01. It has received 1 citations till now. The article focuses on the topics: Zeatin & Endosperm.
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TL;DR: This work is the first reported application of next-generation sequencing techniques for transcriptome analysis of apricot embryo development and the comprehensive set of transcript sequences generated in this study may serve as additional molecular resources for the development of Apricot functional genomics.
Abstract: Apricot (Prunus armeniaca L.) is an important, nutritionally valuable agricultural crop. A scarcity of transcriptomic and genomic data hinders progress toward understanding the molecular events of apricot embryogenesis, which is the primary determinant of fruit yield and kernel quality. In this study, three cDNA libraries were sequenced using an Illumina/Solexa platform. We obtained 35,928,496, 40,656,940, and 35,970,214 clean reads from endosperm formation (LT-A), embryo development (LT-B), and mature embryo (LT-C) cDNA libraries, respectively. De novo assembly of cDNA sequence data generated 35,614 unigenes with an average length of 973 bp. A total of 29,971 unigenes were matched in Nr, Nt, Swiss-Prot, KEGG, GO, and COG databases. The top matching species in the Nr database was P. persica (88.3% of matched Nr database accessions). A total of 8,327 differentially expressed genes (DEGs) were detected between LT-A and LT-B, of which 3,663 were upregulated and 4,664 were downregulated. Between LT-B and LT-C, 12,673 DEGs were detected, while 13,892 DEGs were uncovered between LT-A and LT-C. This work is the first reported application of next-generation sequencing techniques for transcriptome analysis of apricot embryo development. Besides providing valuable information on apricot embryo development, the comprehensive set of transcript sequences generated in this study may serve as additional molecular resources for the development of apricot functional genomics.
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TL;DR: The principal metabolites formed from zeatin by the roots of intact Z. mays seedlings were adenosine-5′-phosphate, zeat in riboside, adenine,Adenosine and an unknown compound termed Y.mays which was isolated and identified as 9-glucosylzeatin.
Abstract: [3H]Zeatin was supplied through the transpiration stream to radish (Raphanus sativus L.) seedlings with roots excised. Formation of dihydrozeatin was not detected but numerous other metabolites were formed, including adenine, adenosine, AMP, zeatin riboside and zeatin riboside-5′-monophosphate. However, in labelled seedlings which had been left in water for 15 h, an unknown compound (raphanatin) was the dominant metabolite and accounted for about 25% of the total radioactivity extracted. A procedure for the isolation of this metabolite was devised and yielded 70 μg from 1600 seedlings. Raphanatin was characterized by mass and ultraviolet spectra and has been identified as 7-glucosylzeatin. It is an active and very stable metabolite which was located mainly in the cotyledon laminae and may be a storage form of the hormone. In contrast, labelled nucleotides, the other major metabolites of zeatin, were largely confined to the hypocotyls and petioles. Zeatin riboside-5′-monophosphate was the dominant metabolite in hypocotyls of de-rooted seedlings supplied with zeatin for 0.5–2 h. The majority of the radioactivity in the xylem sap was due to zeatin, but about 10% was present as zeatin riboside; nucleotides accounted for less than 10% of the radioactivity and labelled raphanatin was not detected.
308 citations
TL;DR: The results demonstrate that the balance between abscisic acid on the one hand and zeatin and gibberellic Acid on the other can effectively control somatic embryo development and either disrupt or ensure normal maturation.
Abstract: The effects of abscisic acid, zeatin, and gibberellic acid on the development of somatic embryos from cultured cells of caraway ( Carum carvi L.) were observed. Somatic embryos complete development on a basal medium without exogenous hormones, but some are subject to developmental abnormalities including malformed cotyledons and accessory embryos. Both zeatin and gibberellic acid, especially in combination, stimulate growth and increase the frequency of aberrant forms. Zeatin causes the formation of multiple shoots, leafy and abnormal cotyledons, and in the dark, enlarged hypocotyls; gibberellic acid effects root elongation, polycotyledony, and some callus formation. In contrast, abscisic acid, at concentrations which do not inhibit embryo maturation, selectively suppresses abnormal proliferations. With abscisic acid, and especially in the dark, a high percentage of embryos complete development with two fleshy cotyledons on unelongated axes free of accessory embryos. In the light, zeatin eliminates abscisic acid inhibition while gibberellic acid only partially counters its effect, promoting elongated radicles and green rather than white cotyledons. In the dark, zeatin in combination with abscisic acid stimulates extensive callusing. Gibberellic acid does not reverse the effects of abscisic acid but rather enhances them and can counter the disruptive effects of zeatin. The results demonstrate that the balance between abscisic acid on the one hand and zeatin and gibberellic acid on the other can effectively control somatic embryo development and either disrupt or ensure normal maturation.
140 citations
89 citations
TL;DR: The soybean callus bioassay was used to determine levels of cytokinin activity in avocado (Persea americana) seeds, finding that in the embryo, levels are high during the early stages of development, but diminish as the fruit grows.
Abstract: The soybean callus bioassay was used to determine levels of cytokinin activity in avocado (Persea americana) seeds.In the embryo, levels are high during the early stages of development, but diminish as the fruit grows. The level of cytokinin activity in the endosperm is very high throughout the period that this tissue exists. The seed coats have very high activity levels while the fruit is young, reaching values comparable with those found in the endosperm. The activity level falls as the rate of fruit growth slows down and disappears completely by the time the seed coats shrivel at approximately the same time the fruit reaches "horticultural maturity".
60 citations
TL;DR: Spray application of 2 millimolar BA to terminal inflorescences at the R(3) developmental stage of field-grown soybeans significantly increased fruit-set and seed yield of the Shore genotype during three growing seasons.
Abstract: The influence of 6-benzylaminopurine (BA) on the premature abscission of developing soybean, Glycine max (L.) Merr. fruits of 2 genotypes was studied. BA was applied during the critical period of fruit-setting. The tested concentration range of BA was from 1 micromolar to 5 millimolar; 2 millimolar was optimal. Spray application of 2 millimolar BA to terminal inflorescences at the R3 developmental stage of field-grown soybeans significantly increased fruit-set and seed yield of the Shore genotype during three growing seasons. In contrast, the Essex genotype gave significant responses two out of three seasons. The response of Shore was generally more pronounced than that of Essex. The apical fruits on the inflorescences gave the greatest response to BA. Seed weight increase was apparent 3-4 weeks after BA treatment.
60 citations