Premature Seeds Research Articles

Effect of Heading Date on the Starch Structure and Grain Yield of Rice Lines with Low Gelatinization Temperature.

Early flowering trait is essential for rice cultivars grown at high latitude since delayed flowering leads to seed development at low temperature, which decreases yield. However, early flowering at high temperature promotes the formation of chalky seeds with low apparent amylose content and high starch gelatinization temperature, thus affecting grain quality. Deletion of starch synthase IIa (SSIIa) shows inverse effects of high temperature, and the ss2a mutant shows higher apparent amylose content and lower gelatinization temperature. Heading date 1 (Hd1) is the major regulator of flowering time, and a nonfunctional hd1 allele is required for early flowering. To understand the relationship among heading date, starch properties, and yield, we generated and characterized near-isogenic rice lines with ss2a Hd1, ss2a Hd1 hd1, and ss2a hd1 genotypes. The ss2a Hd1 line showed the highest plant biomass; however, its grain yield varied by year. The ss2a Hd1 hd1 showed higher total grain weight than ss2a hd1. The ss2a hd1 line produced the lowest number of premature seeds and showed higher gelatinization temperature and lower apparent amylose content than ss2a Hd1. These results highlight Hd1 as the candidate gene for developing high-yielding rice cultivars with the desired starch structure.

Chemical Analysis of Population Variability in Peganum Harmala (var. Harmala)

Both the primary and secondary metabolisms of higher plants are influenced by environmental conditions. Peganum harmala L. synthesise amazing diversity of secondary metabolites, such as alkaloids, volatile oils, triterpenes or sterols. We have no detailed information on genetic chemical contents and particularly the fatty acid contents of this plant species in Iran. Therefore, population-based fatty acid and alkaloid analyses were conducted in four geographical populations. Seeds fatty acid analysis revealed linoleic acid, oleic acid and palmitic acid were the main components in seeds oil. The highest fatty acid component was the linoleic acid in both mature and premature seeds of four studied populations. Low levels of 18:3/18:2 ratio in mature seeds (>0.01) in comparison to premature seeds (> 0.04) were found. Grouping of the populations by WARD clustering, separated mature seeds from premature seeds. CCA plot of P. harmala populations based on fatty acid contents, revealing the influence of geographical features on population differentiation. The main alkaloid contents in premature and mature seeds were harmine and harmaline. PCoA plots of the studied populations based on alkaloid contents for both premature and mature seeds separated the populations from each other.

Effect of germination potential on storage lipids and transcriptome changes in premature developing seeds of oilseed rape (Brassica napus L.).

We provided a gene pool of moderate size for selecting or manipulating the candidate genes that favour the acquisition of seed dormancy, shedding light on the elevation of seed oil content in oilseed rape by blocking lipid degradation in developing seeds. In oilseed rape, the association between the germination potential of premature seeds and the final level of seed lipids, and the underlying mechanism, is elusive. Here, we investigated phenotypic differences in the germination percentage of premature seeds in a collection of oilseed rape cultivars. We compared the dynamic lipid accumulation between the deep-, moderate- and non-dormant genotypes and compared the transcriptomes of the seeds at 40days after pollination between multiple pairs of deep- and non-dormant genotypes. We identified a wide range of differences in germination percentage of premature seeds and the association between the germination potential and the change of fatty acid content at late stage of seed maturation. The comparisons of transcriptomes between deep- and non-dormant seeds revealed the genetic basis for the dormant difference, e.g. the different expression levels of the genes involved in gibberellic and abscisic acid biosynthesis and/or signalling, fatty acid metabolic pathways, and the structure of seed cell wall. We provided a gene pool of moderate size for selecting or manipulating the candidate genes that favour the acquisition of seed dormancy, shedding light on the elevation of seed oil content in oilseed rape by blocking lipid degradation in developing seeds.

Rapid burst of ethylene evolution by premature seed: A warning sign for the onset of spongy tissue disorder in Alphonso mango fruit?

Moisture stress induced in premature seeds due to the breakdown of funiculus in Alphonso mango led to the burst of ethylene evolution, which in turn caused a sudden increase of polyphenol oxidase activity in the pulp, resulting in the development of a black spot near the seed base. Reduced levels of very long chain fatty acids in 70% mature seeds with black spots were associated with a sudden increase of cytokinins followed by a rapid rise of starch-metabolizing enzymes culminating in the onset of pre-germination events. Concurrently, an overproduction of p-OH benzoic acid inhibited amylase and polygalacturonase enzymes and led to partial degradation of the stored starch and pectin in the pulp. A parallel drop in climacteric ethylene production by the pulp led to incomplete ripening coupled with changes in composition, texture and aroma of the pulp, characteristic of spongy tissue. The results have provided strong experimental evidence to support the fact that increased competition for resources among developing fruits for the synthesis of seed fat plays a critical role in spongy tissue formation in Alphonso mango. The major highlight of the study is that rapid ethylene evolution by premature seed is an early warning sign for the initiation of spongy tissue formation in Alphonso mango.

β-Selinene-Rich Essential Oils from the Parts of Callicarpa macrophylla and Their Antioxidant and Pharmacological Activities

Background: Callicarpa macrophylla (Varbenaceae) is a medicinal shrub and is traditionally used in India, China, and South Asia. Methods: The plant material was collected from lower Himalayan region of Uttarakhand in India. The essential oils from three different aerial parts were analyzed by GC-MS. Antioxidant activity, phenolic assay, and various pharmacological activities were determined by using existing methods which are generally practiced widely. Results: Over 51, 53, and 40 compounds were identified in C. macrophylla leaves essential oil (CMLEO), C. macrophylla pre mature seeds and fruits essential oil (CMEO-I) and C.macrophylla mature seeds and fruits essential oil (CMEO-II), respectively. These oils differ in relative contents of major compounds viz; β-selinene (37.51% in CMLEO, 44.66% in CMEO-I and 57.01% in CMEO-II), phyllocladene (9.76% in CMLEO, 5.80% in CMEO-I and 12.38% in CMEO-II), caryophelline oxide (7.34% in CMLEO, 8.74% in CMEO-I and 5.0% in CMEO-II), 9E-epi-caryophelline (6.23% in CMLEO, 1.27% in CMEO-I and 3.43% in CMEO-II), longipinocarvone (4.96% in CMLEO, 1.17% in CMEO-I and 2.0% in CMEO-II), and 1,8-cineole (2.23% in CMLEO, 3.10% in CMEO-I and 1.62% in CMEO-II). The oils exhibited good in vitro antioxidant activity. The maximum activity was found in CMEO-II with IC50 values 7.37 ± 0.11, 11.49 ± 0.87, 14.59 ± 0.18, 15.66 ± 0.03, and 17.49 ± 0.13 µL/mL. The essential oils showed qualitative and quantitative diversity in the makeup of essential oils constituents. The oils were found to exhibit anti-inflammatory, analgesic, and antipyretic activity on swiss albino mice compared to the standard drugs, viz; ibuprofen, paracetamol and indomethacin. Conclusion: It is inferred from the study that the plant parts can be used scientifically in traditional systems as folk herbal medicine. Furthermore, we have generated a database for future reference and judicious exploitation of these oils from their natural setting.

English

Calotropis procera (giant milkweed) is a hardy xerophytic plant, which is distributed globally in many countries and has important economic and ecological functions. The present study aimed at estimating the effect of temperature, salinity and time of fruit dehiscence on the seed germination and seedling morphology of giant milkweed in urban habitats. Seeds were collected early (in June) and late (in December) from pre-dehiscent (EPRD, LPRD) and post-dehiscent (EPOD, LPOD) fruits. Mature seeds were 100% viable, while premature seeds did not germinate. The highest germination and mean time to germination was attained in full dark followed by dark/light, while no germination occurred at complete light. A significant difference between seeds from pre- and post-dehiscent fruits was assessed, while no significant difference between early and late seeds. Maximum germination was at 25 and 30°C, while germination was inhibited at 35°C, which demonstrates that temperature is one of the critical factors for giant milkweed seed germination. Moreover, salinity more than 2000 mg l-1 NaCl inhibited seed germination. It is likely that high temperature, direct light conditions and high salinity are the limiting factors for the establishment of giant milkweed seeds. The germination of C. procera seeds was significantly affected when germinated with Trigonella foenum-vulgare with the reduction of germination from 100 to 34%, while the later plant was not affected. C. procera is considered as an important medicinal plant; therefore, our results provide useful information for its management under different environmental conditions. Key words : Giant milkweed, seed morphology, fruit dehiscence, germination time and viability.

Selection of Drought Tolerant Groundnut Genotypes (Arachis hypogaea L.) Based on Total Sugar and Free Amino acid Content

For the selection of drought tolerant genotype, a field trial was conducted to monitor the quantitative changes of biochemical parameters such as total sugar and total free amino acid, due to water deficit condition in groundnut (Arachis hypogaea L.) seed. Plants were grown in irrigated and non-irrigated conditions. Mature seeds of forty genotypes and premature seeds of twenty one genotypes were freeze dried, defatted, ground and subjected to analysis. Drought exhibited no definite trend of increase or decrease for total free amino acid and sugar in mature as well as premature seed. Premature seed accumulated higher amount of total free amino acid having mean values 1.01% and 0.88% for control and drought respectively, than did the matured ones (control - 0.41% and drought - 0.43%). In mature seeds, drought augmented total free amino acid in twenty one genotypes and retrenched in the remaining nineteen. The data on immature seed was not much useful for selection purpose. In mature seeds of genotypes BINA-Chinabadam-2, 9267, ICGV-97228, ICGV-96295, and ICGV-95412, drought resulted in maximum elevation of total free amino acid. Accumulation of total sugar was higher in mature than in premature seeds. Drought brought about the increase in total sugar in mature seeds of thirty genotypes and decrease in the remaining ten. On imposing water stress, mature seeds of genotypes ICGV-92120, ICGV-94143, ICGV-96295, ICGV-95399 and ICGV-97228 showed comparatively high increment of total sugar. A particular genotype did not appear drought tolerant when the data on both the mature and premature seed are considered. However, in mature seed of genotype ICGV-97228, water stress induced a desired level of change in accumulation of total free amino acid and total sugar, and hence it may be preliminary considered as drought tolerant.DOI: http://dx.doi.org/10.3329/jesnr.v6i2.22077 J. Environ. Sci. & Natural Resources, 6(2): 01-05 2013

A U-Box E3 Ubiquitin Ligase, PUB20, Interacts with the Arabidopsis G-Protein β Subunit, AGB1

An Arabidopsis U-box E3 ubiquitin ligase Plant U-box 20 (PUB20; alternatively called AtCMPG1) was identified as a possible interactor of the Arabidopsis G-protein β subunit, AGB1, by yeast two-hybrid screening. A bimolecular fluorescence complementation (BiFC) assay showed that PUB20 interacted with AGB1 in the nuclei and the cytosol. The expression levels of PUB20 and its closest homolog, PUB21 were stable under many conditions. GUS driven by the PUB20 promoter was active in anthers, pollen, premature seeds and receptacles and GUS driven by the PUB21 promoter was active in anthers and funiculi. PUB20 was found to have autoubiquitination activity in vitro.

Relationships between ion and chlorophyll accumulation in seeds and adaptation to saline environments in Suaeda salsa populations

The importance of ion and chlorophyll accumulation was evaluated in brown seeds of a Suaeda salsa population from an intertidal zone and one from a saline inland zone during seed development. The results showed that more NO3 − and K+, but less Cl− and Na+ in leaves and stems were translocated to the embryos in the intertidal population than the inland population; more Cl− and Na+ were compartmentalized in the pericarps of the intertidal population compared to the inland population, which indicates that the two populations have different ability to accumulate ions in different plant parts. The embryos of fresh premature seeds contained chlorophyll and the embryos could release oxygen. The content of chlorophyll markedly decreased, and there was no oxygen production in the embryos of dry mature seeds in both populations. These characteristics may affect the distributions of the two S. salsa populations in their natural saline environments.

A fast ethanol assay to detect seed deterioration

AbstractThe most common way to test seed quality is to use a simple and reliable but time- and space-consuming germination test. In this paper we present a fast and simple method to analyse cabbage seed deterioration by measuring ethanol production from partially imbibed seeds. The method uses a modified breath analyser and is simple compared to gas chromatographic or enzymatic procedures. A modified method using elevated temperatures (40°C instead of 20°C) shortened the assay time and improved its sensitivity. The analysis showed an inverse correlation between ethanol production and seed quality (e.g. the final percentages or speed of germination and the number of normal seedlings). The increase in ethanol production was observed when cabbage seeds were deteriorated by storage under ambient conditions or hot water treatments, both of which reduced the number of normal seedlings. Premature seeds produced more ethanol upon imbibition than mature seeds. Ethanol production occurred simultaneously with oxygen consumption, indicating that lack of oxygen is not the major trigger for ethanol production.

Rapid Synthesis of Highly Monodisperse AuxAg1−x Alloy Nanoparticles via a Half-Seeding Approach

Gold-silver alloy Au(x)Ag(1-x) is an important class of functional materials promising new applications across a wide array of technological fields. In this paper, we report a fast and facile synthetic protocol for preparation of highly monodisperse Au(x)Ag(1-x) alloy nanoparticles in the size range of 3-6 nm. The precursors employed in this work are M(I)-alkanethiolates (M = Au and Ag), which can be easily prepared by mixing common chemicals such as HAuCl(4) or AgNO(3) with alkanethiols at room temperature. In this half-seeding approach, one of the M(I)-alkanethiolates is first heated and reduced in oleylamine solvent, and freshly formed metal clusters will then act as premature seeds on which both the first and second metals (from M(I)-alkanethiolates, M = Au and Ag) can grow accordingly without additional nucleation and thus achieve high monodispersity for product alloy nanoparticles. Unlike in other prevailing methods, both Au and Ag elements present in these solid precursors are in the same monovalent state and have identical supramolecular structures, which may lead to a more homogeneous reduction and complete interdiffusion at elevated reaction temperatures. When the M(I)-alkanethiolates are reduced to metallic forms, the detached alkanethiolate ligands will serve as capping agent to control the growth. More importantly, composition, particle size, and optical properties of Au(x)Ag(1-x) alloy nanoparticles can be conveniently tuned with this approach. The optical limiting properties of the prepared particles have also been investigated at 532 and 1064 nm using 7 ns laser pulses, which reveals that the as-prepared alloy nanoparticles exhibit outstanding broadband optical limiting properties with low thresholds.

Somatic Embryogenesis in Juniperus Procera using Juniperus Communis as a Model

The study of somatic embryogenesis in Juniperus communis has been conducted as a preliminary study for the further development of somatic embryogenesis, micropropagation and long-term conservation/cryopreservation in Juniperus procera, which is economically and ecologically important and endangered forest species in Ethiopia. The aim for this particular research was initially an adaptation of optimum half strength lithium chloride-sodium propionate (LP) medium protocol for growth and proliferation of embryogenic culture. But as other conifer species it was difficult to stop proliferation of somatic embryo cell division and bring them to maturation stage. However using optimal concentration of ABA (32 mg/l), it was possible to get maturation response in most of the cultures. Additional study on the effect of seed extraction to the growing embryogenic culture showed no effect on mature somatic embryos. Rather they were showing faster growth which increases embryogenic mass of each culture. It was also observed that green premature seeds of Juniperus are suitable for the initiation and proliferation of somatic embryo. Key words: Cryopreservation, Juniperus communis, Juniperus procera, Somatic embryogenesis.

The Effect of Seed Maturity, Temperature and Storage Period on Vigor of Picrasma javanica Bl. Seedling

A study on the effect of seed maturity, temperature and period of storage on vigor of Picrasma javanica Bl. seedling was conducted at the Macropropagation Laboratory, Research Centre of Biology, LIPI, Cibinong, from March to September 2008. The research was arranged using Randomized Block Design with 3 factors and 3 replications, in which each replication had 20 samples. The first factor was stage of seed maturation with 2 levels i.e. pre-mature and mature stage; the second factor was storage temperature with 3 levels i.e. ambient temperature (28±1ºC), 20ºC and 5ºC; and the third factor was storage period with 4 levels i.e. 0, 1, 2, 3 months. The result showed that the germination time of Picrasma javanica seed was varies between 11-23 days. The mature seeds had better growth as compared to pre-mature seeds. Storage on the ambient temperature (28±1ºC) caused decrease of seed vigor, so is not suggested to seeds store in the ambient temperature. The storage under lower temperature (5ºC and 20ºC) was able to maintain seed vigor until 3 months storage.Key words: seeds maturity, temperature, storage period, vigor, Picrasma javanica Bl. seed.

Seed morphology and ultrastructure in Citrus garrawayi (Rutaceae) in relation to germinability

Combinational traits of seed size and seed-coat hardness in Citrus garrawayi (F.M.Bailey) (syn. of Microcitrus garrowayi) were investigated as markers for estimation of seed morphological and physiological maturity. Seed size (length) and coat hardness correlated well with changes in seed coat and embryo morphological development, dry-weight accumulation, decreases in moisture content and a significant increase in germinability. Seed moisture content decreased from 82 ± 1% in immature seeds to 40 ± 1% at seed maturation. The outer integument of immature seeds consisted of thin-walled epidermal fibres from which outgrowths of emerging protrusions were observed. In comparison, mature seed coats were characterised by the thickening of the cell walls of the epidermal fibres from which arose numerous protrusions covered by an extensive mucilage layer. Immature seeds, with incomplete embryo and seed-coat histodiffereniation, had a low mean germination percentage of 4 ± 4%. Premature seeds, with a differentiated embryonic axis, were capable of much higher levels of germination (51 ± 10%) before the attainment of mass maturity. Mature seeds, with the most well differentiated embryonic axis and maximum mean dry weight, had the significantly highest level of germination (88 ± 3%).

Major isoforms of starch branching enzymes in premature seeds of kidney bean (Phaseolus vulgaris L.).

Developing seeds of the kidney bean (Phaseolus vulgaris L.) contain several isoforms of starch branching enzymes. Two of them, KBE1 and KBE2, which are the major forms in the premature seeds, were purified as a single band of protein on SDS-PAGE and native PAGE by chromatographies on DEAE-Sepharose, Bio-Gel P-200, and amylose-binding Sepharose 6B. The enzymes had similar pH optimum (7.0), pH stability (7.0-9.5), temperature optimum (25-30 degrees C), and temperature stability (up to 40 degrees C). Additionally, both were inhibited by various divalent metal ions and activated by citrate. Finally, though their N-terminal amino acid sequences were identical, their molecular masses and affinities for amylose differed; 80 kDa and 1.27 mM for KBE1 and 77 kDa and 0.74 mM for KBE2.

Evidence that ethylene, light and abscisic acid interact to inhibit germination in the recalcitrant seeds ofQuercus roburL.

The effects of ethylene, light and abscisic acid (ABA) on the germination of prematurely-harvested and mature Q. robur seeds were studied. There was evidence of active biosynthesis of ethylene, but not of ABA in seeds from both harvests. Addition of ABA, the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) or the ethylene-releasing compound Ethephon (E) to germination media and exposure to light individually inhibited germination and their effects were additive. The ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG) tended to promote germination of premature seeds only

Studies on the Development of the Desiccation-sensitive (Recalcitrant) Seeds of Avicennia marina (Forssk.) Vierh.: The Acquisition of Germinability and Response to Storage and Dehydration

Germinability and responses to storage and dehydration were studied throughout the development of the desiccation-sensitive seeds of Avicennia marina. Seeds acquired the ability to produce roots at 55 d after fruit set (DAFS) which is shortly after histodifferentiation, but the capacity for full germinability (seedling establishment) was not attained until 70 DAFS, which is midway through the phase of growth and reserve accumulation. Pre-mature seeds showed a germination lag that was equivalent to the period between harvest and full maturity, but, following short-term storage, this was reduced to that of mature seeds. At no stage, however, would seeds with an intact pericarp germinate.Once seeds were fully germinated, storage lifespan under non-desiccating conditions was independent of developmental stage, but was considerably reduce by the presence of the pericarp, probably because of fungal contamination. Prior to the acquisition of full germination capacity, the seeds were unable to tolerate any dehydration but became tolerant to slight water loss once they became fully germinable, after which desiccation sensitivity was not influenced by the stage of development. If rapidly dried, excised axes of germinable seeds survived to lower water contents than did axes removed from seeds following slower drying.