Seeds Of Several Plant Species Research Articles

Perspectives for a Framework to Understand Aril Initiation and Development.

A differentiated structure called “aril” has been described in seeds of several plant species during the course of evolution and might be considered as a supernumerary integument. Besides its ecological function in seed dispersal, the structure also represents a relevant character for systematic classification and exhibits important properties that impart agronomic value in certain species. Little is known about the molecular pathways underlying this morphological innovation because it is absent in currently used model species. A remarkable feature of the seeds of Passiflora species is the presence of a conspicuous aril. This genus is known for the ornamental, medicinal, and food values of its species. In view of the molecular resources and tools available for some Passiflora species, we highlight the potential of these species as models for developmental studies of the aril.

English

The G. microtarsus is a small marsupial belonging to the Didelphidae family and may be found mainly in the Atlantic Rainforest of the Brazilian Southeastern region. G. microtarsus has important ecological importance in the dispersion of seeds of several plant species. Current research characterizes morphologically six tongues of adult male and female specimens, which are fixed in 10% formaldehyde. The tongues were analyzed, measured and photographed in situ and ex situ . Anatomy, light microscopy and ultrastructural analysis were performed. Macroscopically the tongue has root, a fixed body and a free apex. The tongue has fungiform papillae and high conical and acute filiform papillae across the dorsal surface. It also featured three vallate papillae located at the root and marginal fungiform papillae at the apex. Microscopically, the tongue is composed of longitudinal and transversal muscle fibers. Blood vessels, nerves, serous, mucous and mixed acini are found in non-modeled connective tissue. Ventrally, the tongue is lined by a keratinized stratified pavement epithelium. The morphology of the tongue of G. microtarsus resembles that described in carnivores and marsupials Didelphidae regarding its microscopic structure, differing only in the distribution and number of papillae.

Subterranean Watercourses may ‘Rescue’ Seeds Dispersed by Fruit-Eating Bats in Caves

Seeds of several plant species are frequently wasted, if dispersed to unsuitable microsites. Some microsites, such as the interior of large caves, are unsafe for animal-dispersed seeds. However, sometimes a second dispersal agent may give these seeds a second chance of survival, thus playing the role of ‘seed rescuer’. We tested this hypothesis by investigating the seed fate of plant species dispersed by fruit-eating bats in an Amazonian cave and by evaluating whether those seeds could be rescued by a subterranean watercourse. We measured seed arrival at the ground and the watercourse. We also collected seeds coming out of the cave through the watercourse. Banara sp. was the most abundant morphospecies, followed by Cecropia sp., Solanum sp. and Vismia sp. We collected 1,751 seeds of seven morphospecies in water. Cecropia sp. was the most abundant species. Experimental data showed that on average 37% of the seeds of Banara, Vismia, and Cecropia leaving the cave were viable. A second experiment detected dif...

ANESTHETIC RELEASE OF SEED DORMANCY—AN OVERVIEW

ABSTRACT Anesthetic-type compounds enhance the germination of dormant seeds of several plant species. The most effective compounds are ethanol, ethyl ether, and chloroform, which are used either in aqueous solutions or as vapors. They interact strongly with phytochrome in promotion of seed germination by light. The activities of the compounds are considered to arise from influences on the seed membranes.

Why fruits are rich in antioxidants? An opinion review,

We rarely consider whether and how plants benefit from making antioxidant-rich fruits, despite our dependence on fruits as routine sources of these compounds. The hypothesis presented here is that storage of the antioxidant materials is advantageous to the survival of the plant species. This hypothesis is based on the premise that at different stages from flower bud opening to seedling formation, the concentrations of the reactive oxygen species (ROS) needed vary tremendously. Exposing seeds of several plant species to ROS aids germination. However, ROS can cause considerable damage by mutagenesis during plant embryogenesis. It is suggested that the antioxidant-rich environment in fruits protects the developing plant embryos from this damage. It also allows for an antioxidant environment for packaging the embryos into seeds with tight seed coats. After fruit maturation and seed dispersal, a prolonged exposure to oxygen and moisture enables the seeds to produce the ROS needed for seed germination. There is a simultaneous increase in the ROS scavenging systems to allow for protection of the dividing cells afterwards. These observations are unified into the hypothesis that the antioxidant rich fruits aid in the survival of plant species, and discussed in the context of vascular plant evolution.

Characterization of fatty acid composition from five perilla seed oils in China and its relationship to annual growth temperature

Omega-3 fatty acids have been shown to reduce inflammation and may help prevent chronic diseases like heart disease and arthritis. Alpha-linolenic acid is a type of w-3 fatty acids and has been reported with a remarkably high content (>50%) only in seeds of several plant species, for example, Perilla and Linum usitatissimum L. It is a valuable compound obtained from plants which can provide health benefits similar to those derived from fish oil. In this study, five seed samples from five varieties of the monotypic genus Perilla collected from five provinces in China were analyzed to determine their fatty acid composition. The seed oils were extracted using Soxhlet, and oil contents of these samples ranged from 33.25 to 42.58% (wt/wt). Fatty acid compositions were then analyzed using gas chromatography-mass spectrometry (GC-MS). Saturated, monounsaturated and polyunsaturated fatty acids accounted for 9.16 to 10.49, 13.78 to 20.93 and 63.12 to 73.45% of their totals, respectively, in which the content of the unsaturated fatty acids was over 90% on average. Moreover, a-linolenic acid was dominant (52.58 to 61.98%) in all the oil samples, and it comprised 65.67 to 68.37% of the total unsaturated fatty acids and 83.30 to 84.38% of the polyunsaturated acids, respectively. However, contents of the w-6 linoleic acid in the five samples were only 10.54 to 15.87%, and the ratio of w-6 to w-3 fatty acids was as low as 0.2 to 0.26. The results indicate that Perilla oil is presently the best quality oil derived from plant sources and hence it could be developed into commercial products to serve as a valuable alternative vegetable oil. Furthermore, oil from seeds obtained in regions with lower average growth temperature has relatively higher percentage of unsaturated fatty acids. Key words: Annual growth temperature, gas chromatography-mass spectrometry (GC-MS),w-3 a-linolenic acid, w-6 linoleic acid, Perilla, seed oil, variety.

Exposure to red light, temperature and exogenous gibberellins influenced germination of some winter weeds

Red light, temperature and gibberellins are well known for their capacity to induce higher germination in dormant seeds of several plant species. In the current study, we investigated the effect of various temperature (10, 13, 16, 19, 22 and 25°C) and gibberellic acid (GA 3 ) and GA 4+7 concentrations (0.1, 1, 10, and 100 uM) on germination of Poa annua, Alopecurus aequalis and Stellaria aquatica seeds incubated under continuous dark or treated with red light pulse of 80 mol m -2 s -1 red light (660 nm) for 10 min after 12 h of dark period. We found that incubation temperature and gibberellins (GAs) significantly enhanced seed germination in red light treated seeds, as maximum germination was observed for A. aequalis (67.3% at 13°C), P. annua (61.3% at 13°C), and S. aquatica (42% at 19°C) in such treatments. Exogenous GA 4+7 significantly promoted germination of P. annua and A. aequalis seeds, while GA 3 induced higher germination in S. aquatica seeds. It was observed that GAs were more effective in the presence of red light as least germination stimulation was recorded for GAs under dark condition and no germination was found in weed seeds at control and 0.1 mM GA 3 and GA 4+7 treatments. It can be concluded that lower temperature (13°C) and GA 4+7 in conjunctions with red light pulse, induced maximum germination in dormant weed seeds. Key words : Germination, temperature, nitrogen-containing compounds, red light, gibberellins.

Divergent Chemical Cues Elicit Seed Collecting by Ants in an Obligate Multi-Species Mutualism in Lowland Amazonia

In lowland Amazonian rainforests, specific ants collect seeds of several plant species and cultivate them in arboreal carton nests, forming species-specific symbioses called ant-gardens (AGs). In this obligate mutualism, ants depend on the plants for nest stability and the plants depend on ant nests for substrate and nutrients. AG ants and plants are abundant, dominant members of lowland Amazonian ecosystems, but the cues ants use to recognize the seeds are poorly understood. To address the chemical basis of the ant-seed interaction, we surveyed seed chemistry in nine AG species and eight non-AG congeners. We detected seven phenolic and terpenoid volatiles common to seeds of all or most of the AG species, but a blend of the shared compounds was not attractive to the AG ant Camponotus femoratus. We also analyzed seeds of three AG species (Anthurium gracile, Codonanthe uleana, and Peperomia macrostachya) using behavior-guided fractionation. At least one chromatographic fraction of each seed extract elicited retrieval behavior in C. femoratus, but the active fractions of the three plant species differed in polarity and chemical composition, indicating that shared compounds alone did not explain seed-carrying behavior. We suggest that the various AG seed species must elicit seed-carrying with different chemical cues.

The effect of Azotobacter vinelandii on plant seed germination and adhesion of these bacteria to cucumber roots

Bacterization of seeds of several plant species with Azotobacter vinelandii suspension stimulates their germination to different degrees. This demonstrates that seeds of different species display different sensitivity to the biologically active substances accumulating in the culture liquid of these bacteria. The adhesion patterns of these bacteria to cucumber roots were studied. The maximal number of cells adhered to the root surface at the phase of culture logarithmic growth (24 h), when they were motile. The loss of motility in the stationary growth phase (72 h) decreased the number of cells adhered to roots by 80%.

Frutos como item alimentar não habitual do morcego carnívoro Chrotopterus auritus (Mammalia, Phyllostomidae) da região sudeste do Brasil

We record here the occurrence of seeds of several plant species in feces found inside the day roost of Chrotoperus auritus , at the Estacao Experimental de Itirapina, State of Sao Paulo, Southeastern Brazil, in July 2001. The roost was used by only one adult female, non pregnant, during about a month. In the feces, fur of rodent (Muridae), bone fragments, fragments of Scarabaeidae and other beetles and insects, leaves (not determined) and many seeds of Piperaceae ( Piper sp.), Urticaceae ( Cecropia sp.) and Solanaceae ( Solanum spp. and Cestrum sp.) were found. In the gut content, insect fragments, fur of rodent (Muridae) and plant remains were found. It was discussed why this carnivorous bat would be consuming plant items.

Fruits as unusual food items of the carnivorous bat Chrotopterus auritus (Mammalia, Phyllostomidae) from southeastern Brazil

We record here the occurrence of seeds of several plant species in feces found inside the day roost of Chrotoperus auritus, at the Estação Experimental de Itirapina, State of São Paulo, Southeastern Brazil, in July 2001. The roost was used by only one adult female, non pregnant, during about a month. In the feces, fur of rodent (Muridae), bone fragments, fragments of Scarabaeidae and other beetles and insects, leaves (not determined) and many seeds of Piperaceae (Piper sp.), Urticaceae (Cecropia sp.) and Solanaceae (Solanum spp. and Cestrum sp.) were found. In the gut content, insect fragments, fur of rodent (Muridae) and plant remains were found. It was discussed why this carnivorous bat would be consuming plant items.

Food Habits and Seed Dispersal by the White-Eared Opossum, Didelphis albiventris, in Southern Brazil

The food habits and seed dispersal promoted by the marsupial Didelphis albiventris (Marsupialia: Didelphidae) were investigated in two forest fragments of Curitiba, southern Brazil, between February 1995 and February 1997. Forty live traps were set uniformly in the fragments for opossum captures and collection of their scats. Diet was determined by fecal analysis and seed dispersal was tested through seed germination experiments. With a total of 1842 traps set, 71 scats of the white-eared opossum were collected, and 51 contained seeds. The opossum is omnivorous, consuming invertebrates (100% of occurrence in scats), fruits (76%) and vertebrates (58%). Common animal food items were those found in the litter. Diversities of food items were similar among opossums of different age classes. Seeds of several plant species passed undamaged through the guts and remained viable. Fruits from pioneer plants were the main ones consumed. Based on these results, this omnivorous opossum must be an effective seed disperser in southern Brazil.

Effects of Seed Dispersal by Three Ateline Monkey Species on Seed Germination at Tinigua National Park, Colombia

We examined the effect of seed ingestion by three ateline primates: woolly monkeys, Lagothrix lagothricha; spider monkeys, Ateles belzebuth; and, red howler, Alouatta seniculus on germination rates and latency periods of seeds of several plant species in Tinigua National Park, Colombia. We collected dispersed seeds from feces and control seeds from the parental trees and washed them for germination trials. For the majority of plants, dispersed seeds germinated as well or better than control seeds did. Although spider monkeys depend more heavily on fruits than the other monkey species do, they were not more efficient than howlers or woolly monkeys at improving germination rates. A considerable proportion of the seeds dispersed by howlers and woolly monkeys showed reduced latency periods to germination, but spider monkeys showed less effect on reducing germination time. This result may be related to longer gut retention times, but such a trend has not been observed in other primate species. We conclude that, like many other primates, ateline monkeys are effective seed dispersers in terms of their effects on the seeds they swallow because they rarely decrease their germination rates. We discuss problems that make interspecific comparisons difficult, such as inappropriate control seeds and differences associated with germination substrates, and we stress the importance of studying other components of seed dispersal effectiveness.

Predator-mediated interactions among the seeds of desert plants.

In theory, seed predators are capable of inducing indirect interactions among the seeds they consume. However, empirical evidence of predator-mediated interactions among seeds is rare. Rodents in the Heteromyidae are highly granivorous and therefore likely to induce indirect interactions among the seeds of desert plants. The indirect interactions may be in the form of apparent competition and apparent mutualism between seeds within a patch. Apparent competition exists when the survival of seeds of a focal species is lessened because of the presence of additional seeds of other species in the patch. Apparent mutualism exists when the presence of the other seeds results in an increase in survival of seeds of the focal species. By measuring seed removal from trays placed in the field, apparent competition between the seeds of several plant species was detected. Apparent mutualism might also exist, but there was no strong evidence of it. Apparent competition appeared most likely to occur among the species whose seeds were the most heavily predated. For instance, predation on seeds of Astragalus cicer, Oryzopsis hymenoides, and Sphaeralcea coccinea was substantial with more than 50% of the seeds removed from the trays, on average. The intensity of apparent competition (measured by the indirect effect, IS) between these species and two others was significant; IS ranged from -0.02 to -0.39 on a scale of 0 to -1. This indicates that, in some communities, indirect effects are most likely to exist when direct effects are strong.

N-Acylethanolamines in seeds. Quantification Of molecular species and their degradation upon imbibition

N-Acylethanolamines (NAEs) were quantified in seeds of several plant species and several cultivated varieties of a single species (cotton [Gossypium hirstutum]) by gas chromatography-mass spectroscopy. The total NAE content of dry seeds ranged from 490 +/- 89 ng g(-1) fresh weight in pea (Pisum sativum cv early Alaska) to 1,608 +/- 309 ng g(-1) fresh weight in cotton (cv Stoneville 7A glandless). Molecular species of NAEs in all seeds contained predominantly 16C and 18C fatty acids, with N-linoleoylethanolamine (NAE18:2) being the most abundant (approaching 1,000 ng g(-1) fresh weight in cottonseeds). Total NAE levels dropped drastically following 4 h of imbibition in seeds of pea, cotton, and peanut (Arachis hypogea cv Virginia), and this decline was most pronounced for NAE18:2. A novel enzyme activity was identified in cytosolic fractions of imbibed cottonseeds that hydrolyzed NAE18:2 in vitro. NAE degradation was optimal at 35 degrees C in 50 mM MES buffer, pH 6.5, and was inhibited by phenylmethylsulfonyl fluoride and 5, 5'-dithio-bis(2-nitrobenzoic acid), which is typical of other amide hydrolases. Amidohydrolase activity in cytosolic fractions exhibited saturation kinetics toward the NAE18:2 substrate, with an apparent K(m) of 65 &mgr;M and a V(max) of 83 nmol min(-1) mg(-1) protein. Total NAE amidohydrolase activity increased during seed imbibition, with the highest levels (about four times that in dry seeds) measured 2 h after commencing hydration. NAEs belong to the family of "endocannabinoids," which have been identified as potent lipid mediators in other types of eukaryotic cells. This raises the possibility that their imbibition-induced metabolism in plants is involved in the regulation of seed germination.

Tissue-specific localization of aspartic proteinase in developing and germinating barley grains

Resting seeds of several plant species, including barley grains, have been reported to contain aspartic proteinase (EC 3.4.23) activity. Here, the expression of the Hordeum vulgare L. aspartic proteinase (HvAP) was studied in developing and germinating grains by activity measurements as well as by immunocytochemical and in-situ hybridization techniques. Southern blotting suggests the presence of one to two HvAP-encoding genes in the barley genome, while Northern analysis reveals a single 2.1-kb mRNA in grains and vegetative tissues. Western blotting with antibodies to HvAP shows the same subunit structure in different grain parts. In developing grains, HvAP is produced in the embryo, aleurone layer, testa and pericarp, but in the starchy endosperm HvAP is present only in the crushed and depleted area adjacent to the scutellum. During seed maturation, HvAP-encoding mRNA remains in the aleurone layer and in the embryo, but the enzyme disappears from the aleurone cells. The enzyme, however, remains in the degenerating tissues of the testa and pericarp as well as in resting embryo and scutellum. During the first three days of germination, the enzyme reappears in the aleurone layer cells but is not secreted into the starchy endosperm. The HvAP is also expressed in the flowers, stem, leaves, and roots of barley. The wide localization of HvAP in diverse tissues suggests that it may have several functions appropriate to the needs of different tissues.

Observations on Organic Volatiles from Germinating Seeds and Seedlings

Germinating seeds of several plant species evolved oxidizable volatile compounds, including aliphatic aldehydes. Formaldehyde comprised only a small percentage of the total aldehydes detected. Most seeds evolved these compounds only during the first three or four days after imbibition, with peak production occurring during the second day. In general, larger seeds evolved greater quantities than smaller seeds, but, on a unit weight basis, smaller seeds evolved more. Dry, non-germinating, or killed seeds evolved little or no volatiles, indicating that active seed metabolism was required for the production of volatiles. The light-dark regime appeared to have little effect on volatile evolution.

OBSERVATIONS ON ORGANIC VOLATILES FROM GERMINATING SEEDS AND SEEDLINGS

Germinating seeds of several plant species evolved oxidizable volatile compounds, including aliphatic aldehydes. Formaldehyde comprised only a small percentage of the total aldehydes detected. Most seeds evolved these compounds only during the first three or four days after imbibition, with peak production occurring during the second day. In general, larger seeds evolved greater quantities than smaller seeds, but, on a unit weight basis, smaller seeds evolved more. Dry, non‐germinating, or killed seeds evolved little or no volatiles, indicating that active seed metabolism was required for the production of volatiles. The light‐dark regime appeared to have little effect on volatile evolution.

Metoda ilościowego określania składu pożywienia gryzoni

Opracowano metodę ilościowego oznaczania składników roślinnych treści żołądkowej gryzoni. Sporządzano mieszaniny wysuszonych drobnych fragmentów części wegetatywnych i nasion kilku gatunków roślin w znanych proporcjach wagowych i rozcieńczano je dodając na mg mieszanki 0,04 ml wody. Po dokładnym wymieszaniu określano pod mikroskopem powierzchnię zajmowaną przez wszytkie fragmenty roślinne znajdujące sie w polu widzenia mikroskopu.

Occurrence of Substances Similar to Gibberellic Acid in Higher Plants

IF the fungal metabolite gibberellic acid is applied to dwarf varieties of pea, french bean (Phaseolus), broad bean (Vicia) or maize, growth is greatly accelerated and plants similar to the normal tall phenotype are produced; the tall varieties themselves are much less affected by gibberellic acid, if at all1,2. This suggests that this acid, or a substance with similar physiological properties, is a normal plant-growth regulator, produced less abundantly in dwarf varieties than in tall ones. The growth-promoting substance obtained from immature bean seeds by Mitchell, Skaggs and Anderson3 was probably of this type; more recently, West and Phinney4 have reported the probable occurrence of substances like gibberellic acid in seeds of several plant species; I have obtained evidence of such a substance in the shoots of dwarf and tall peas, and this is summarized below.