Glucosinolates In Seeds Research Articles

Chemotaxonomic Diversity and Complexity in Seed Glucosinolates of Caulanthus and Streptanthus (Cruciferae)

Seed glucosinolate profiles (kinds and proportions of constituents) were analyzed by paper- and gas-chromatography for 89 collections of 40 species of Caulanthus and Streptanthus. Twenty-six compounds were identified; these are pre- sumed to be biosynthesized from five different protein amino acids. Considerable interspecific variability was uncovered, with differences involving both the number of glucosinolates constituting a profile (diversity) and the nature of biosynthetic modifications affecting their production (complexity). Serpentine-adapted taxa ap- pear to be as chemically diverse and complex as non-serpentine taxa. In general, a species possesses a characteristic chemical profile distinguishable from that of mor- phologically similar taxa. In six species significant intraspecific variability was de- tected; in S. cordatus this variability correlates with morphologically recognized infra- specific taxa. Suspected parallelism and convergence, however, reduce the taxonomic utility of glucosinolates as characters at subgeneric and generic levels in this group of Cruciferae. Caulanthus S. Wats. and Streptanthus Nutt. are two morphologically similar and presumably phylogenetically related genera of North Amer- ican Cruciferae. Together they comprise about 45 species of annual to perennial herbs that usually occupy dry, open habitats from sea-level to montane elevations. Species delimitation within each of the two and their separate generic status have been matters of long-standing controversy (cf. Payson 1923; Jepson 1925; Kruckeberg 1958; Munz 1959; Rollins 1971; Al-Shehbaz 1973; Rollins and Holmgren 1980)-an issue of some political as well as biological consequence because rare and endangered populations of these plants may be entitled to legal protection only if they constitute named taxa. As members of the putatively primitive tribe Thelypodieae, the two genera figure prominently in recent discussions on the phylogeny of Cruciferae, including place of origin and early di- versification (Al-Shehbaz 1973; Raven 1975; Hedge 1976). With the goals of testing current classifications of these genera and of describing new characters for anticipated revision and phylogenetic analysis, we initiated a paper- and gas-chromatographic survey of the glucosinolates (mustard oil glucosides) in seeds of these plants.

Population Variation and Hybridization in Sea-Rockets (Cakile, Cruciferae): Seed Glucosinolate Characters

Population Variation and Hybridization in Sea-Rockets (Cakile, Cruciferae): Seed Glucosinolate Characters

Sinalbin and other glucosinolates in seeds of double low rape species and Brassica napus cv. Bronowski.

Sinalbin and other glucosinolates in seeds of double low rape species and Brassica napus cv. Bronowski.

Differentiation and Migration of Cakile (Cruciferae): Seed Glucosinolate Evidence

Paperand gas-chromatographic analyses for seed glucosinolates are reported for 20 natural and two botanical garden samples of Cakile, thus completing coverage of all 14 taxa in the genus throughout its native and naturalized range. Sixteen glucosinolates, deriving from three major biosynthetic pathways, were identified. Plants with distinctive and characteristic arrays of seed glucosinolates (chemical races) generally correspond to morphologically recognizable species or subspecies. Chemical differentiation in the genus involved diversification in Mediterranean strand populations, follozwed by simplification in glucosinolate composition coincident with further evolutionary migration in the Old World and to the New TWVorld. Glucosinolates (mustard oil glucosides; Ettlinger 8c Kjar, 1968), a class of thioglucosides restricted to approximately 5,000 species of dicotyledons, have been the focus of numerous interesting ecological investigations (Whittaker & Feeny, 1971; Feeny, 1975, for a partial listing). Less convincingly have they been demonstrated to be of systematic interest and utility. Merxmiiller and Leins (1967) advocated the separation of the Rhoeadales into the orders Capparales and Papaverales by citing, among other characters, the presence of glucosinolates (and of the associated enzyme myrosinase in specialized myrosin cells) in the former and apparent absence in the latter. Kjar (1974) suggested that the occurrence of glucosinolates in the Limnanthaceae and Tropaeolaceae strengthened Cronquist's view (1968) that these families are phylogenetically related. Few comprehensive studies have been undertaken at lower taxonomic ranks, however, and one of the foremost investigators of these secondary plant products could write recently (Kjar, 1974): At the genus and species level knowledge of the glucosinolate pattern has, in a few cases, been put to good use as an auxiliary character in analyzing delimitations. The data available are, however, insufficient to define their specific merits for such purpose. Recent monographs of the cruciferous genera Thelypodium (Al-Shehbaz, 1673) and Cakile (Rodman, 1974) now clearly demonstrate the taxonomic utility of these compounds and reveal the potential of glucosinolate analyses for studies of evolutionary differentiation, migration, hybridization and introgression, and coevolution. The first report on Cakile (Rodman, 1974) presented data on seed 1 I thank Ihsan Al-Shehbaz, Hansjoerg Eichler, James Mandaville, Jr., and especially Martin G. Ettlinger for their generous gifts of seed samples. This study was supported in part by National Science Foundation Grant BMS-75-0331 1. 2 Biology, Yale University, New Haven CT 06520. This content downloaded from 207.46.13.181 on Thu, 14 Apr 2016 06:57:26 UTC All use subject to http://about.jstor.org/terms 138 SYSTEMATIC BOTANY [Volume 1

ω-Methylthioalkylglucosinolates and some oxidized congeners in seeds of Erysimum rhaeticum

The glucosinolates in seeds of Erysimum rhaeticum Schleich. ex DC. have been identified by structure analysis of their sulfur-containing enzymic hydrolysis products, comprising 5-methylthiopentyl and 6-methylthiohexyl isothiocyanate, the corresponding 3-hydroxylated isothiocyanates, and the sulfoxides and sulfones of the latter. The phytochemical results are evaluated in terms of their possible taxonomic significance.

Glucosinolates in seeds of Neslia paniculata

The glucosinolate fraction in seeds of Neslia paniculata (L.) Desv., subsp. thracica (Velen.) Bornmüller, (Cruciferae), has been isolated and subjected to enzymic hydrolysis. The isothiocyanates thus produced have been separated and identified as cheirolin (II), ( R)-9-methylsulfinylnonyl (III), ( R)-10-methylsulfinyldecyl (IV), and ( R)-11-methylsulfinylundecyl isothiocyanate (V), the last of which has not been previously encountered as a natural compound.

Genetische und physiologische untersuchungen zur bildung von glucosinolaten in rapssamen: Lokalisierung des hauptbiosyntheseortes durch pfropfungen

Summary Crossing experiments with the Brassica napus variety «Bronowski» (low in glucosinolate in seed) have shown (a) that high glucosinolate content of normal rape seed is inherited as a dominant character and that (b) the genotype of the embryo has no significant effect on quantity and composition of glucosinolates in seeds. This (quantity and composition of glucosinolates) depends on the genetic constitution of the mother plant, and indicates that the site of glucosinolate-biosynthesis is unlikely to be in seeds. Therefore we tried to localize the site of glucosinolate synthesis by grafting experiments using «Bronowski» (low glucosinolate) and «Zero erucic» (high glucosinolate). The main observations from reciprocal grafting studies were: 1. Whenever siliques or shoots of Zero Erucic were grafted on Bronowski, the quantity and composition (isothiocyanates and thiooxazolidones) of glucosinolates in seeds of the scion were identical with those of ungrafted Zero Erucic plants. Quantity and composition of glucosinolates in seeds of the stock were not influenced by the scion. These results indicated that (a) siliques (smallest grafting unit used in our experiments) are the main sites of biosynthesis for those glucosinolates which are stored in seeds, and that (b) the stock Bronowski is able to produce and transport to siliques all precursors needed for glucosinolate biosynthesis. Since we could not find any indication for an increased glucosinolate breakdown in Bronowski plants, it appeared that the low glucosinolate content of this genotype may be the result of a blocked glucosinolate biosynthesis. 2. In the reciprocal combination (when siliques and shoots of Bronowski were grafted on stocks of Zero Erucic) we found an increase in the final amount of glucosinolates in seeds of the scion. This was higher in seeds produced on grafted siliques than on grafted shoots. The composition of these glucosinolates which give rise to the increase, corresponded to the glucosinolate composition of seeds produced on Zero Erucic stock or on ungrafted Zero Erucic plants. This demonstrates that while most of the glucosinolates stored in seeds are synthesized in siliques, a part is synthesized also in other plant organs. The actual cause for the increase of glucosinolates could not however be determined. It is possible that either the glucosinolates themselves may be produced by the stock of Zero Erucic and translocated to the seeds of the Bronowski scion, or that some intermediate products may be translocated to the scion from which Bronowski is able to complete the biosynthesis of glucosinolates.

Glucosinolates in Seeds of Arabis hirsuta (L.) Scop.: Some New, Naturally Derived Isothiocyanates.

Glucosinolates in Seeds of Arabis hirsuta (L.) Scop.: Some New, Naturally Derived Isothiocyanates.

Glucosinolates in Lepidium bonariense L.

The major glucosinolate in seeds of the South American crucifer Lepidium bonariense L. is shown to be the p-hydroxybenzylglucosinolate (glucosinalbate) ion (Ia), isolated as the tetramethylammonium salt and characterized as a potassium salt of the corresponding pentaacetate. The second, and minor, glucosinolate undergoes enzymatic hydrolysis with the production of p-methoxybenzyl isothiocyanate, typically formed from p-methoxybenzylglucosinolate (glucoaubrietin) (Ib). The seeds also contain sinapine, isolated as the thiocyanate. These results are at variance with a recent literature report on the glucosinolates in L. bonariense.