Comparative analysis of metabolome of rice seeds at three developmental stages using a recombinant inbred line population

Plants are considered an important food and nutrition source for humans. Despite advances in plant seed metabolomics, knowledge about the genetic and molecular bases of rice seed metabolomes at different developmental stages is still limited. Here, using Zhenshan 97 (ZS97) and Minghui 63 (MH63), we performed a widely targeted metabolic profiling in seeds during grain filling, mature seeds and germinating seeds. The diversity between MH63 and ZS97 was characterized in terms of the content of metabolites and the metabolic shifting across developmental stages. Taking advantage of the ultra‐high‐density genetic map of a population of 210 recombinant inbred lines (RILs) derived from a cross between ZS97 and MH63, we identified 4681 putative metabolic quantitative trait loci (mQTLs) in seeds across the three stages. Further analysis of the mQTLs for the codetected metabolites across the three stages revealed that the genetic regulation of metabolite accumulation was closely related to developmental stage. Using in silico analyses, we characterized 35 candidate genes responsible for 30 structurally identified or annotated compounds, among which LOC_Os07g04970 and LOC_Os06g03990 were identified to be responsible for feruloylserotonin and l ‐asparagine content variation across populations, respectively. Metabolite?agronomic trait association and colocation between mQTLs and phenotypic quantitative trait loci (pQTLs) revealed the complexity of the metabolite?agronomic trait relationship and the corresponding genetic basis.     

红火蚁对8种植物种子的选择性取食及其对种子萌发的影响

在室内研究了红火蚁Solenops isinvicta种群对玉米、绿豆、芥蓝、芝麻、番茄、水稻、藿香蓟及象草等8种植物种子的选择性取食及其对种子萌发的影响,结果表明红火蚁对芝麻种子最为喜好,且刮啃率最高（82．4％）,对芝麻、藿香蓟、象草及芥蓝种子具有较高的搬运率（分别为100．0％、72．0％、44．0％及41．6％）和丢弃率（分别为86．4％、50．4％、79．2％及88．9％）。通过观察回收种子的萌发,结果表明红火蚁对芝麻、藿香蓟和象草种子的破坏最为严重,导致其未能正常萌发的种子分别占总数的64．3％、56．0％及49．7％。因此,通过上述指标可以判断红火蚁入侵后对芝麻、藿香蓟和象草种子存在较大潜在威胁。     

two 3-oxo steroids in Thea sinensis seeds

Spinasterone and 22,23-dihydrospinasterone were isolated from the seed oil of Thea sinensis which contains spinasterol and 22,23-dihydrospinasterol as the two major sterol constituents.     

种子的脱水行为及其分子机制

成熟脱水是种子发育的末端事件。根据种子的脱水行为,可以把种子分为正常性、顽拗性和中间性种子。许多过程或者机制授予或者提高种子的脱水耐性,不同的过程可能在不同的水合水平上对水分丧失起保护作用,这些过程的缺乏或者无效表达可能决定个别物种的种子的脱水敏感性程度。到目前为止,涉及种子脱水耐性的过程或者机制有：细胞内脱分化;代谢的‘关闭’;抗氧化系统的存在和有效运转;保护性分子(包括胚胎发育后期高丰度表达蛋白,蔗糖、寡糖或者半乳糖苷环多醇,亲水脂分子,油素)的存在;以及在重新水合过程中修复机制的存在和运转。     

磁化水浸种对苦瓜种子萌发及对其幼苗生理指标的影响

目的 :研究磁化水对苦瓜种子萌发的影响。方法 :用不同强度的磁化水浸种处理苦瓜种子 ,测定其以下几个生理指标 :种子的发芽率、发芽指数、活力指数和幼苗中的酯酶以及抗坏血酸的含量。实验结果显示 :磁化水能够提高苦瓜种子的发芽率、发芽指数、活力指数 ,同时也能提高苦瓜幼苗的酯酶活性 ,但对抗坏血酸含量影响不大。结论 :一定强度的磁化水能提高苦瓜种子的萌发能力 ,并使幼苗生长整齐一致。     

Comparative analysis of cell cycle events in zygotic and somatic embryos of Cyclamen persicum indicates strong resemblance of somatic embryos to recalcitrant seeds

Embryo development and germination of Cyclamen persicum have been comparatively characterized for zygotic and somatic embryos with regard to mitotic activity and morphology in order to identify developmental abnormalities in somatic embryogenesis. Zygotic embryo development proved to be highly synchronous with distinct periods of cell division, cell elongation and embryo maturation within a total period of 17 weeks of seed development. Somatic embryo development was accomplished within only 3 weeks, resulting in a mixture of morphologically highly variable embryos. No distinct developmental periods could be identified and no reduction of the mitotic activity was discovered for non-desiccated somatic embryos. Controlled desiccation of somatic embryos severely reduced their germination rate, demonstrating resemblance of somatic embryos to recalcitrant seeds, whereas zygotic Cyclamen seeds could be characterized as typically orthodox.     

Nouveaux acides amines libres de Afzelia bella: trans-hydroxy-4-L-proline et trans-carboxy-4-L-proline

Two new free amino acids have been isolated from seeds of Afzelia bella: trans-4-hydroxy-L-proline and trans-4-carboxy-L-proline. They are accompanied by relatively large quantities of proline, pipecolic, acid, 4-methylene-DL-proline, cis-4-hydroxymethyl-L-proline and 4-methylene-L-glutamic acid. Small amounts of acetylornithine are also present. It is the first time that trans-4-hydroxy-L-proline has been found as a component of the free amino pool of plants.     

Characterization of three members of the Arabidopsis carotenoid cleavage dioxygenase family demonstrates the divergent roles of this multifunctional enzyme family

Arabidopsis thaliana has nine genes that constitute a family of putative carotenoid cleavage dioxygenases (CCDs). While five members of the family are believed to be involved in synthesis of the phytohormone abscisic acid, the functions of the other four enzymes are less clear. Recently two of the enzymes, CCD7/MAX3 and CCD8/MAX4, have been implicated in synthesis of a novel apocarotenoid hormone that controls lateral shoot growth. Here, we report on the molecular and genetic interactions between CCD1, CCD7/MAX3 and CCD8/MAX4. CCD1 distinguishes itself from other reported CCDs as being the only member not targeted to the plastid. Unlike ccd7/max3 and ccd8/max4, both characterized as having highly branched phenotypes, ccd1 loss-of-function mutants are indistinguishable from wild-type plants. Thus, even though CCD1 has similar enzymatic activity to CCD7/MAX3, it does not have a role in synthesis of the lateral shoot growth inhibitor. Rather, it may have a role in synthesis of apocarotenoid flavor and aroma volatiles, especially in maturing seeds where loss of function leads to significantly higher carotenoid levels.     

试论种子顽拗性的复合数量性状特征

文章简要概述了从顽拗型种子到顽拗性种子这样一个对顽拗性种子认识提高的过程,在综述了前人关于顽拗性种子数量性状特征论述的基础上,把种子顽拗性的数量性状特征划分为种间、种内和个体发育三个层面,提出种子顽拗性是一种复合性状,其核心至少包括脱水耐性、低温耐性和贮藏耐性三方面的内容,其伴随性状包括种子尺度、千粒重、初始含水量、休眠特性、分类地位、地理分布和保护性物质含量等多方面的内容,而且这些核心内容和伴随性状的每一个方面都具有渐变的、过渡的、数量型的特征,从而阐明种子顽拗性是一种复合数量性状.种子顽拗性的复合数量性状特征的提出及其三个层面的划分,有助于加深对种子顽拗性的认识,并用以指导我们在实践中解决种子顽拗性方面的具体问题.     

Dehydrin expression in seeds and maturation drying: a paradigm change

Dehydrins are well known for being expressed in leaves during the course of developmental processes as well as under drought stress, being part of the protective machinery. Moreover, in seed physiology, dehydrins are classified as late embryogenesis‐related proteins (LEA protein), where they are thought to be responsible for persistence and longevity of seeds. Although both topics are a focus of modern plant biology, a direct linkage between these both areas is generally lacking. Based on an alignment of the chain of events, this paper will help to generate understanding that the occurrence of dehydrins in maturing seeds and leaves suffering drought stress is part of the same basic principle: basic principle: dehydrins are expressed in response to water shortage. Unfortunately, the related developmental process in seeds, i.e. maturation drying, has not been adequately considered as a part of this process. As a corresponding implication, the chain of events must be adjusted: the differences in dehydrin expression in orthodox, intermediate and recalcitrant seeds could be directly attributed to the occurrence or absence of maturation drying. The differences in dehydrin expression in orthodox, intermediate and recalcitrant seeds, and thus the differences in longevity, could be attributed to the occurrence or absence of a maturation drying.     

花生种子劣变过程中一些酶活性的变化

应用20%聚乙二醇处理花生种子8小时,种子活力提高。表现在过氧化氢酶活性较高,过氧化物含量较低,外渗液电导率下降。萌发3天幼苗的超氧物歧化酶和过氧化氢酶活性均高于对照。萌发3天种子的活力指数和21天幼苗生长量均有明显提高。由萌发3天种子子叶分离出线粒体,在悬浮液中的酸性磷酸酯酶活性和 DNA 酶活性均明显降低。     

珍稀濒危植物金丝李种子脱水耐性和贮藏特性

为测定不同脱水程度金丝李(Garcinia paucinervis)种子的萌发情况及其复水后的吸水率、脱水过程中抗性生理指标的变化以及不同贮藏方式下种子的萌发情况,该文研究了金丝李种子的脱水敏感性和储藏特性。结果表明:(1)金丝李种子初始含水量为45.29%,室内通风处放置35 d失水率即达45%。(2)种子失水率低于18%时,萌发率和复水后的吸水率变化不显著;失水率超过18%时,萌发率和复水后吸水率均显著下降,失水率为42%时萌发率为0。其种子的临界含水量为27.29%,半致死含水量为12.72%。(3)随着种子脱水程度的加深,相对电导率、可溶性糖及脯氨酸含量逐步上升;丙二醛含量在失水率低于24%时变化不大,高于24%时显著提高; SOD和POD的活性均呈波动性变化,失水率为18%时活性均最高。(4)室温干藏1个月和-1、-20℃下湿藏1个月的种子均不能萌发;水浸贮藏1个月的种子萌发率显著降低; 4℃湿藏1、3和6个月均显著延缓种子萌发,但对萌发率无显著影响。表明金丝李种子在失水率低于18%时,种子可通过抗性调节维持细胞的正常代谢,能忍受一定程度的脱水和低温;当失水率超过18%时,种子代谢失衡发生劣变直至死亡,属于低度的顽拗性种子。4℃湿沙藏(含水量7.5%)是短期贮藏其种子的较好方法。     

Establishment of chasmogamous and cleistogamous seedlings of an ant-dispersed UNDERSTORY HERB,CALATHEA MICANS (Marantaceae)

This study compares the establishment success of cleistogamous (CL, obligately selfed) and chasmogamous (CH, potentially outcrossed) seeds of the neotropical understory herb, Calathea micans (Marantaceae). In this species, CH and CL seeds are morphologically identical and are both dispersed by ants. I measured dispersal distances and analyzed seedling recruitment and seedling size for ant-planted CH and CL seeds, a protocol made possible by the fact that the seed coat of C. micans can be indelibly marked and remains attached to the base of the seedling for a few months. Seeds were taken by ants from experimental depots placed in natural conditions. In a second experiment, I planted CH and CL seeds in gap and understory sites to determine the effects of seed type and light on germination percentage, date of emergence, and seed and seedling survivorship. Ant-planted CH and CL seedlings did not differ in dispersal distance. CH and CL seeds did not differ significantly in recruitment probability and seedling size in either experiment. However, for the ant-planted seedlings, CH recruitment was higher in the understory than in the gap, while CL recruitment was uniform across light environments. In conclusion, I found a difference in the establishment success of CH and CL seeds in this understory herb, only after dispersal by ants in field conditions.     

Propagation of three orchid genera using encapsulated protocorm-like bodies

Summary Protocorm-like bodies (plbs) of the orchid Dendrobium ‘Sonia’ were obtained from fractionated plb explants on Murashiga and Skoog (1962) medium (MS) supplemented with 4.44 μM 6-benzylaminopurine (BA). The developmental stage of plbs to be encapsulated, concentrations of sodium alginate (2–5%) and calcium chloride (25–100 mM), and concentration of MS salts in the matrix were assessed. Fractionated plbs 13–15 d after culture were at the leaf primordia stage and found suitable for encapsulation studies. The best encapsulation response was observed with 3% sodium alginate upon complexation with 75 mM CaCl₂.2H₂O. An encapsulation matrix prepared with MS medium (three-quarter strength) supplemented with 0.44 μM BA and 0.54 μM α-naphthaleneacetic acid gave 100% conversion of encapsulated plbs to plants after storage. A viability of >85% of encapsulated plbs of Dendrobium ‘Sonia’ was observed for 75 d at 4°C. Encapsulated plbs of orchids Dendrobium, Oncidium, and Cattleya were stored at 4°C for 75, 60 and 30 d, respectively, with >88% germination. All plants survived potting in media having either wood charcoal pieces alone or in combination with brick pieces.     

Seed maturation time influences the germination requirements of perennial grasses in desert climate of Arabian Gulf

Qatar has a dry, subtropical desert climate, with minimum annual rainfall and intensely hot and humid summers. Using indigenous grass, those adapted to local conditions have the potential to be used for fodder and can also be used for restoration or rehabilitation of degraded rangelands. Chloris virgata, Coelachyrum brevifolium and Cenchrus ciliaris bloom twice a year from April to May (summer) and September to October (winter) under the nursery condition. Therefore, it is important to understand, how seeds produced in different seasons affect the dormancy as well as germination of these species. Seeds of C. virgata, C. brevifolium and C. ciliaris, three desert grasses, were collected from the plants growing on Shahniya nursery in two different seasons, summer (May) and winter (October). The seeds collected in May (summer) were stored up to winter. However seeds collected in October (winter) were immediately used for experiment. We compared the germination potential of seeds that matured in different season at different alternating temperatures at 15/25, 20/30 and 25/35 °C. Lower temperatures correspond to the dark period, while higher temperatures reflect the light period. Seeds collected in summer season (old seeds) were heavier as compared to seeds collected in winter season (new seeds). Winter seeds of C. virgata seem to be dormant, while summer seeds, germinated well in all the tested temperature regimes. However, C. ciliaris seeds showed opposite trends.     

Vicilin from Anadenanthera colubrina Seeds: An alternative tool to combat Callosobruchus maculatus

Vicilins are seed proteins, and they constitute 70–80% of the total protein in leguminous seeds; with amolecular mass between 150 and 190 kDa, they are composed of subunits without disulfide bridges, with high affinity for chitin-binding. They are also associated with seed defense against insect pests. The chitin-binding vicilin from Anadenanthera colubrina seeds was purified by ammonium sulfate, followed by affinity chromatography on a chitin column, molecular exclusion on Superdex 75 Tricorn in FPLC system and Phenomenex C8 chromatography in HPLC system. The A. colubrina vicilin, named AcV, is a tetrameric glycoprotein composed of 1.55% carbohydrates and molecular weight determined by SDS-PAGE, consisting of 70, 73, 43 and 41 kDa. The AcV homogeneity was confirmed in native PAGE, where it was observed to be a unique band with slow mobility in this gel, with approximately 230 kDa. AcV added to the Callosobruchus maculatus diet in the bioassays resulted in a strong effect on adult emergence (ED50 of 0.096%), and in larvae caused a marked reduction in mass (WD50 of 0.32%) and lethality (LD50 of 0.33%) (w:w). The digestibility of AcV was evaluated in vitro with the digestive enzymes of larvae of C. maculatus of fourth instar, showing major fragments of 10 and 30 kDa. AcV showed reactivity against the anti-EvV antibody from Erythrina velutina vicilin. The deleterious effects of AcV are likely to be associated with the chitin-binding fragments generated by proteolysis in the bruchid gut, similarly to that found for vicilins from other leguminous plant species, Enterolobium contortisiliquum and Vigna unguiculata. AcV might be a candidate protein for a possible bioinsecticidal control of the bruchid weevil, C. maculatus.     

Effect of samh seeds supplementation (Mesembryanthemum forsskalei Hochst) on liver enzymes and lipid profiles of streptozotocin (STZ)-induced diabetic Wistar rats

Thirty streptozotocin (STZ)-induced diabetic of Wistar Albino rats were divided into five groups. The rat groups received different food (natural diet or high fat content diet) supplemented with 10% or 15% of samh seeds for 6 weeks. At the end of the study, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phophatase (ALP) and lactate dehydrogenase (LDH) enzymes have been measured in diabetic rats liver. In addition, liver lipid profile (total cholesterol (TC), triglyceride (TAG), lipid peroxide production malondialdehyde (MDA)) and reduced glutathione (GSH) in have been measured in diabetic rats liver, and the levels of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) were also determined. The samh seeds diet supplemented with cholesterol significantly increase (P < 0.05) the levels of liver peroxide production MDA, TC and TG in diabetic rats comparing to the samh diet not supplemented with the cholesterol. However, the samh seeds significantly decrease (P < 0.05) the level of GSH. These data suggest that the samh seeds diet not supplemented with the cholesterol regulated C and TG metabolism and decrease the lipid peroxidation in the diabetic rats.     

Buried seed population in the herbaceous lomas on Loma Ancon in the coastal desert of central Peru

Herbaceous lomas in the Peruvian coastal desert, of South America establish in spring, and its habitat is limited to the southern or southwestern slopes along the coast that are affected by thick fog. The time of appearance, the duration and the thickness of the fog vary greatly from year to year, so the lomas can grow only in habitats with enough water to, sustain seed germination and plant growth. This paper studies the species composition and density of the buried seed population, of the herbaceous lomas of Loma Ancon in order to clarify the mechanisms of the lomas' establishment. The mean number of species with viable seeds was about, 12 spp. m⁻² and that of dead seeds was about 22 spp. m⁻². The dominant species wereSolanum tuberiferum, S. pinnatifidum andNolana humifusa, both in viable and dead seeds. Viable seed density was about 5000–8000 seeds m⁻², which is comparable with the seed densities of other herbaceous communities. Dead seed density was about 15000–27000 seeds m⁻², or nearly three times the viable seed density, because the rate of decomposition was slow in the extremely dry conditions. The net increase of viable seeds by seed production was estimated at about 5000 seeds m⁻² in 1980, and the increase in the number of dead seeds was 2200 seeds m⁻².