Seed Coat Types Research Articles

Variation for seed coat and pod wall percentage and other traits in a germplasm collection and historical cultivars of lupins

Accessions totalling 1425 from the Australian Lupin Collection representing 9 Old World lupin species and Lupinus mutabilis Sweet, a New World species, were sampled for seed coat and pod wall percentage, seed weight, and number of seeds per pod. These traits are of importance to the breeding objective of lowering seed coat and pod wall proportions in crop lupins. Seed coat percentage mean values among the species ranged from 12.7 in L. mutabilis to 33.7 in L. pilosus L. The 4 species that have been subject to selection (L. mutabilis, L. albus L., L. angustifolius L., and L. luteus L.) had lower mean seed coat percentages than the other species with little domestication. The rough-seeded lupin species had higher seed coat percentages relative to the smooth-seeded species except for L. micranthus Guss., which had 31.5% seed coat and small seeds. Within L. angustifolius there was no difference between the mean seed coat percentage values for wild v. domesticated or hard v. soft-seeded entries, although wild accessions of L. angustifolius tended to have lower seed weight, higher pod wall percentage, and more seeds per pod than domesticated accessions. There was no correlation in L. angustifolius germplasm between seed coat percentage and pod wall percentage, indicating that selection for one will not influence the other character. Accessions with the lowest seed coat percentage were from Turkey, Greece, and Cyprus, and those with the lowest average pod wall percentage were from Spain and Cyprus. Mean pod wall percentages ranged from 30.9 in L. albus to 57.1 in L. micranthus; figures that are high compared with other legumes. Large ranges in seed weight were found particularly in L. albus, L. pilosus, and L. angustifolius. In addition to the germplasm collection, 21 Australian cultivars, released from 1967 to 1999, were evaluated at one site over 2 years for the same traits. There was a negative correlation between seed coat percentage and seed weight for both L. angustifolius historical cultivars and germplasm, indicating that further reductions in seed coat percentage could be achieved by crossing large seeded types with low seed coat types. Pod wall percentage was negatively correlated with both year of release and yield, and positively correlated with days to flowering. These data support other findings that breeding for the reduction of pod wall can lead to yield improvements. The germplasm collection assessed here provides lines with lower seed coat and pod wall compared with what is available in breeding lines or cultivars.

Carpology, Seed Anatomy and Taxonomic Relationships ofTetracentron(Tetracentraceae) andTrochodendron(Trochodendraceae)

This study of the anatomy and morphology of fruits and seeds ofTrochodendron aralioidesSieb. & Zucc. andTetracentron sinenseOliv. has revealed significant new data in the understanding of their systematic and phylogenetic relationships. The correction of the seed coat type forTrochodendronas (endotestal-) exotegmic (instead of endotestal) and forTetracentronas exotegmic (instead of endotestal) documents a large morphogenetic gap between these putatively advanced types of seed coat and those of other Hamamelididae. Among primitive angiosperms, the combination of a few-layered testa with a markedly differentiated endotesta and a relatively multilayered tegmen with a sclerified tracheidal exotegmen occurs only in the seeds of the family Dilleniaceae (Dilleniales), which occupies a somewhat isolated position within the subclass Dilleniidae. The former features, as well as characteristics of node anatomy, anther dehiscence, pollen, floral and fruit morphology, suggest a close relationship between Trochodendrales and Dilleniales. The intermediate position of Trochodendrales between Magnoliidae and Hamamelididae is rejected, and Trochodendrales are taxonomically transferred from Hamamelididae to Dilleniidae in the rank of a distinct superorder: Trochodendranae. It is considered necessary to reform further the systematics of the artificial complex of the so-called ‘lower’ Hamamelididae and Dilleniidae. The suggested relationship betweenTrochodendronand fossil forms such asTrochodendroides, Nordenskiöldia, TrochodendrocarpusandTrochodendrospermumis also found untenable in light of the carpological survey of modern forms presented here.

Seed-coat anatomy in Fumariaceae-Fumarioideae

Seed-coat anatomy is described in 122 species of Fumarioideae, which represent all the genera, subgenera, and most sections. Nine seed-coat types were recognized: (I) Dicentra subg. Hedycapnos , (II) Dicentra subg. Chrysocapnos , (III) Dicentra subg. Macranthos , (IV) Dicentra subg. Dicentra , (V) Corydalis p.p. , (VI) rest of Corydaleae, Cysticapnos, Pseudofumaria and Ceratocapnos , (VII) Discocapnos and Sarcocapnos p. p. , (VIII) Sarcocapnos p. p., Platycapnos and Trigonocapnos , and (IX) Fumariinae. Variable characters are polarized based on the comparison with Fumariaceae-Hypecooideae, Papaveraceae and Pteridophyllaceae. It is assumed that endotestal seed-coat type (I) is most primitive, that exotestal seed-coat types (II–VIII) are derived therefrom, and that the reduction of the mechanical layer, including the origin of thin seedcoat type (DC) occurred repeatedly in combination with indehiscent, hard-walled fruits. Dicentra subg. Hedycapnos (with type I) possesses a combination of primitive testai characters unique within the subfamily, suggesting it represents a sister group to the rest of the subfamily. Each of the other subgenera (with II, III or IV) is also characterized by a unique combination of seed-coat characters, which are found in the outgroups but not in the other genera. Seedcoat characters support the monophyly of Fumarioideae exclusive of Dicentra subg. Hedycapnos , Fumarioideae exclusive of Dicentra , of Dicentra subg. Dicentra , of Corydalis p.p. , and of Fumariinae.

Soybean Seed Coat Structures: Relationship to Weathering Resistance and Infection by the Fungus Phomopsis phaseoli

The fungus Phomopsis phaseoli (Desmaz.) Sacc. (syn. P. sojae Lehman) incites a serious disease of soybean [Glycine max (L.) Merr.] seeds. This study was conducted to determine if an impermeable seed coat reduces infection by this fungus. Seeds of four soybean cultivars found in blotter tests to be infected by P. phaseoli in very low amounts (0–5%) and seeds of four other cultivars with high amounts of infection by this fungus (65–83%) were studied under scanning electron microscopy. Seed coats of cultivars with low P. phaseoli infection were found to lack pores, whereas those with high infection had multiple pores. In addition, seeds of the four cultivars with low infection had closed micropyles, whereas those with high infection had relatively open micropyles. This was reflected in their measurements: closed micropyles had an average area of 0.17 mm2, compared with 0.44 mm2 for the open ones. The percentage of impermeable seed coats in the eight cultivars was determined by soaking seeds in distilled water for 1 h. The average percentage of seeds with an impermeable seed coat was 75% for the four cultivars with low infection and 5% for those with high infection. In a field study, in which pairs of cultivars with either normal or impermeable seed coats were compared, there were significant differences between the two seed coat types in amount of P. phaseoli infection at maturity and after field weathering. This study supports the theory that the resistance of certain soybean cultivars to infection by P. phaseoli is due to the physical characteristics of impermeable seed coats.

Systematic Significance of Seed-Surface Features in Orthocarpus (Scrophulariaceae-Subtribe Castillejinae)

Scanning electron microscope and light microscope examination of seed-coat features of 26 species of Orthocarpus have allowed recognition of many species-level differences (summarized in a key) and of three seed-coat types that parallel taxonomic subgroups but support realignments at generic and infrageneric levels. Type 1 seeds (subg. Orthocarpus, sect. Orthocarpus) have a lateral hilum, sculptured inner tangential seed-coat walls, and a tightly fitting outer seed coat. They are very similar to seeds of Cordylanthus. Seeds of Types 2 and 3 have a terminal hilum and membranous inner tangential cell walls. Type 2 seeds (subg. Orthocarpus, sects. Castillejoides and Cordylanthoides, with one exception) have a net-like, loosely fitting outer seed coat that shows close relationship to seeds of Castilleja. Inner tangential walls of Type 2 seeds normally rupture. Type 3 seeds (subg. Triphysaria, with two exceptions) have a tightly fitting outer seed coat and inner tangential walls are always retained. Seed features support evidence from floral morphology and chromosome numbers that Orthocarpus as currently recognized is not a monophyletic lineage.

Seed-Coat Morphology and Anatomy in Collomia (Polemoniaceae)

Seed-coat morphology of 14 species of Collomia (Polemoniaceae) was examined with light microscopy and scanning electron microscopy. Two seed types were observed based on surface sulpturing: Type 1—hexagonal epidermal cells forming a shallow reticulum with well-defined cell boundaries; Type 2—longitudinally ridged and irregularly arranged crater-like depressions with inconspicuous cell boundaries. Only two species, C. debilis and C. larsenii of sect. Collomiastrum have seed-coat Type 1. Seed-coat Type 2 is characteristic of all species of sect. Collomia, sect. Courtoisia, and C. mazama, C. rawsoniana of sect. Collomiastrum. The present investigation reveals a fairly homogeneous seed-coat pattern in the genus and does not offer significant information for realignment of infrageneric classification. Anatomical studies with light microscopy show that a mucilaginous seed coat develops from the outermost layer of integument in which each epidermal cell develops spiral secondary wall thickenings. Mucilaginous seeds of most Collomia species probably provide adaptive significance in that adherence of seeds to ground prohibits further dispersal to unfavorable habitats, or epizoochoric dispersal.

Genetic analysis of seed-coat types in interspecific Vigna hybrids via SEM

Genetic analysis of seed-coat types in interspecific Vigna hybrids via SEM

SEED COAT MORPHOLOGY IN CORDYLANTHUS (SCROPHULARIACEAE) AND ITS TAXONOMIC SIGNIFICANCE

A study of seed coat sculpturing in Cordylanthus (Scrophulariaceae—Rhinantheae) using the scanning electron microscope (SEM) shows that seed surface patterns are characteristic and constant for a given species or a group of species. Seeds of 23 species were examined and classified into four types (irregularly crested, deeply reticulate, shallowly reticulate, and irregularly striate) based on differences in the reticulated seed coat. Anatomical studies of sections with the light microscope show that the reticular patterns result from enlargement of the epidermal cells of the integument, followed by formation of characteristic wall patterns through lignification. Seed characters furnish useful data for formulating the taxonomy of Cordylanthus both on the sectional and subsectional level and for the delimitation of certain species. Seed coat morphology offers evidence for including the genus Dicranostegia in Cordylanthus and for maintaining C. hispidus and C. palmatus as separate species. The distinctness of two seed coat types within section Cordylanthus suggests two major phylogenetic lines within this section.

Studies on the classification and geographycal distribution of local varieties of vegetables in Japan. II

From his histological observation on the seed coat of varieties of turnip KONDO (1933) found that there are two types, that is Type A; in which epidermal cells of the seed swell with water and Type B; in which epidermal layer appears to be only membranous. The seed coat of the Type A is dominant over the Type B in turnip (SHIBUTANI 1952). In the previous paper on local varieties of turnip, the author reported that varieties of the Type A are distributed in the western Japan, while those of the Type B in the eastern Japan. Both turnip and non-heading mustard (n=10group) belong to the same group in Brassica.For this study the author collected several local varieties of non-heading mustard in Japan and investigated their various characters, especially the histological type of the seed coat, in order to establish the relation between the kind of non-heading mustard and the type of the seed coat and to discuss the distribution of seed-coat type in Japan.The results of the investigation are summarized as follows:1. The local varieties of non-heading mustard in Japan are classified as shown in table 4.2. The epidermal layer of the seed coat in varieties belonging to B. pekinensis, B. chinensis, B. campestris, and B. narinosa is of the Type B in most of the cases, with a few cases of the Type A (Hiroshimana and Yamato-mana) and of the mixed type (for example, Sangatsuna).3. The seed coat of varieties belonging to B. japonica is of the Type A in every case, so that it is certain that the seed-coat of B. japonica is fundamentally of the Type A unlike other species.4. In B. Rapa and B. campestris varieties distributed in the eastern of Japan produce seeds of the Type B, while those distributed in the Kansai region produce seeds of the Type A.5. From this investigation on non-heading mustard in Japan, it is concluded that varieties distrib uted in the eastern Japan produce seed of the Type B in general, while those distributed in the western Japan produce seeds of the Type A, similar to the distribution of seed-coat type in local varieties of turnip.6. Many of these varieties have hairy leaves. so that it is presumed that these local varieties have originated from a hairy variety.7. The bolting season of varieties cultivated in the warm region, except for Kyona group, were usually earlier than those of varieties cultivated in the cool region.8. Based on the above mentioned results, the author discussed on the origin of B. japonica and the gene of the Type A.

INHERITANCE AND ASSOCIATION OF OIL AND PROTEIN CONTENT AND SEED COAT TYPE IN SESAME, SESAMUM INDICUM L

INHERITANCE AND ASSOCIATION OF OIL AND PROTEIN CONTENT AND SEED COAT TYPE IN SESAME, SESAMUM INDICUM L