Seed coat thickness in the evolution of angiosperms

The seed habit represents a remarkable evolutionary advance in plant sexual reproduction. Since the Paleozoic, seeds carry a seed coat that protects, nourishes and facilitates the dispersal of the fertilization product(s). The seed coat architecture evolved to adapt to different environments and reproductive strategies in part by modifying its thickness. Here, we review the great natural diversity observed in seed coat thickness among angiosperms and its molecular regulation in Arabidopsis.     

High K+ content explains the abolition of the action potential in amphibian sciatic nerve in vitro byLathyrus sativus seed extract

Summary The action potential in amphibian sciatic nerve in vitro has been reported to be abolished by the topical application ofLathyrus sativus seed extract. We have confirmed this effect, but find that it is probably caused by the high K⁺ content of such seed extracts and that organic neurotoxins are not implicated.Acknowledgments. We thank the Wellcome Trust for financial support, Professor M.W. Bradbury for help with the ion determinations and Miss M.B. Burbridge of the Tropical Products Institute, London, for obtaining seed from Bombay, India.     

Amount of ribosomal DNA and seed protein content in the genusTriticum

Summary rRNA/DNA hybridization experiments were performed and seed protein content was determined in several lines of 4 species ofTriticum (wheat). No correlation between rRNA gene number and seed protein content was found.Supported by CNR contract No. 74/0267.     

白菜内生细菌的分布规律初探

为了探明细菌在白菜体内的分布规律,有目的地开发生防制剂,进行了华良六号和上海五月慢2个白菜品种不同器官中内生细菌的数量分布及菌的特性研究。研究结果表明:白菜的种子、根、茎、叶中均存在大量的内生细菌,内生细菌的分布特点因不同品种和不同器官而存在一定的差异,根中的内生细菌数量比其它器官中要多,内生细菌以G 菌和芽胞杆菌为优势菌群,种子中内生细菌数量多的品种,其各器官中的内生细菌数量也相对要多。内生细菌在植株中的分布数量受培养条件的影响,在无菌栽培条件下,内生细菌的数量要比在自然土栽培条件下的数量多。     

Structure and function of the fig

Summary An overview is given of the functional anatomy of the fig. The fig is the site of pollination and oviposition, it produces wasps, seeds and pollen, and it is the unit of dispersal. Therefore the fig acts as both a flower and a fruit. When a flower is both fertilized and receives a wasp egg, it eventually produces a wasp. Fertilization in flowers that do not recieve a wasp egg initiates seed production. Wide variation exists in the structural features of figs among different subgenera and sections. Monoecious species and gynodioecious species have different strategies for maintaining the symbiosis with the pollinating fig wasps. Monoecious species produce wasps and seeds in a single fig type and show imperfect heterostyly. Gynodioecious species have specialized figs for wasp and for seed production and are characterized by perfect heterostyly.     

Aristotle and Galen on sex difference and reproduction: a new approach to an ancient rivalry

[I]n contrast to Aristotle's male oriented explanation of procreation the Galenic was 'feminist' inasmuch as both sexes were presented as contributing equally in conception and accordingly both had to experience pleasure... Anatomically, the two sexes were presented in Galenic accounts as complementary, the difference being that the man's genitalia were on the outside and the woman's on the inside. The clitoris was likened to the penis and the ovaries considered 'testicles' or 'stones' that produced seed. The male seed was, it is true, depicted by Galenists as superior in having 'spiritual' qualities lacking in the female, but Galen's reproductive schema was far more egalitarian than Aristotle's. (McLaren, 1985, p. 327)     

Identification of uncommon amino acids in the lentil seed (Lens culinaris Med.).

The fraction of the free basic amino acids in the lentil seed was shown to contain gamma-hydroxyarginine, gamma-hydroxyornithine and homoarginine besides the common amino acids. Similar distribution was found in 5 varieties of lentil, with hydroxyarginine and arginine dominating. The significance of these findings with regard to chemotaxonomy and lentil consumption is discussed.     

Selection for resistance to azadirachtin in the green peach aphid,Myzus persicae

Two lines ofMyzus persicae of the same origin were treated repeatedlywith pure azadirachtin (aza), or a refined neem seed extract (NSE), at the equivalent concentration of aza. After 40 generations, the aza-selected line had developed 9-fold resistance to aza compared to a non-selected control line, whereas the NSE-selected line did not. These results suggest that a blend of active constitutents in a botanical insecticide such as neem might diffuse the selection process, mitigating the development of resistance compared to that expected with a single active ingredient.     

The effect of sugar nutrition of in vitro pollinated placentae on seed set and dormancy inNicotiana tabacum L.

Summary The substitution of sucrose in the nutrient medium for in vitro pollinated placentae by glucose and fructose favours seed formation and considerably enhances the germination of seeds just attaining maturity. This effect of invert sugar was wholly suppressed in the mixture with two parts of sucrose.     

关中麦棉集约式栽培技术模式研究

本试验针对陕西关中棉区气侯特点与种植习惯,研究了夏棉春育、麦林移栽、麦后覆膜等项麦棉集约式两熟栽培技术,扩展夏棉生长的时空和热量条件。三年试验结果表明,在“三密一稀”满幅荷种植的麦田,麦收前育苗移栽、麦后采取覆膜管理等措施,可增加≥15℃有效积温535．6-525．8℃,使夏棉皮棉产量达1197．5～981．0kg·hm^-2。比麦林点播棉籽的一般露地管理夏棉增产皮棉89．4％,较好的解决了当地棉麦两熟栽培有效热量不足的最小限制因子,实现了麦棉集约式两熟作务,提高了土地等资源的利用率。     

Effect of germination on the glycoprotein of mash (Phaseolus mungo) seeds

Summary The soluble carbohydrates and insoluble proteins ofPhaseolus mungo seeds decreased considerably up to 96 h of germination, whereas the soluble proteins remained nearly constant. The carbohydrates content of glycoprotein also remained constant. This suggests that a negligible change took place in the glycoprotein during the initial period of mash seed germination.     

化感活性物质影响种子萌发作用机理的研究进展

化感作用由于其独特的生物学特性而受到广泛关注,并逐渐成为近年来的研究热点。然而目前多数的化感作用研究关注于化感物质对幼苗生长的影响以及化感物质的分离、鉴定、提纯,而对化感物质影响植物种子萌发的作用机理缺乏足够的重视。本文主要论述了化感作用的概念、发展以及化感物质降低种子萌发率、改变激素平衡、破坏生物膜结构、影响种子呼吸代谢等一系列生理活动的作用机理。最后对今后化感作用的研究重点进行展望,强调应着重进行化感物质作用机理的精确研究,从分子、基因水平进行探讨。     

The effects of legume seed extracts on plant virus infection

Summary Extracts from the seeds of 15 species of legume inhibited the infection of plants by viruses. Extracts could be divided into those with marked inhibitory activity reducible on heating and those with less marked inhibitory activity which increased on heating. Evidence is given to suggest that seed extracts contain both virus inhibitors and augmenters and that the inhibitors are high molecular weight proteins possibly related to lectins.     

The reported occurrence of L-canavanine in soya bean,Glycine max

Summary The reported occurrence of L-canavanine in soya bean,Glycine max could not be verified by enzyme treatment of the extracted non-protein amino acids of the seed.This work was supported by a grant from the National Science Foundation (BMS-75-19770) and funds from N.I.H. Biomedical Grant 5-SO5-RR07114-08.The author thanks Dr D. B. Egli of the University of Kentucky for soya bean seeds and Karen Hughes for her technical assistance.     

The effects of legume seed extracts on plant virus infection

Extracts from the seeds of 15 species of legume inhibited the infection of plants by viruses. Extracts could be divided into those with marked inhibitory activity reducible on heating and those with less marked inhibitory activity which increased on heating. Evidence is given is given to suggest that seed extracts contain both virus inhibitors and augmenters and that the inhibitors are high molecular weight proteins possibly related to lectins.     

Canavanine in alfalfa (Medicago sativa)

Summary Canavanine was extracted and characterized from various cultivars of alfalfa seed. Values obtained range from 8 g/kg for the Buffalo variety to 14–20 g/kg for the highly weevil resistant variety, Weevl-Chek.     

Variation in the fatty acid composition of developing seeds of rapeseed

Summary A study was made of the variation in the fatty acid composition of the oil in the developing seed of the Rafal cultivar of theBrassica napus L. cultivated in central Italy. The oil content reaches its maximum level 60 days after the petals fall. The increase in the percentage of oleic acid is negatively correlated with the palmitic, stearic and linoleic acid content.     

Identification of uncommon amino acids in the lentil seed (Lens culinaris Med.)

Summary The fraction of the free basic amino acids in the lentil seed was shown to contain -hydroxyarginine, -hydroxyornithine and homoarginine besides the common amino acids. Similar distribution was found in 5 varieties of lentil, with hydroxyarginine and arginine dominating. The significance of these findings with regard to chemotaxonomy and lentil consumption is discussed.     

Flavonol glycosides and seed coat structure in certain species ofEpilobium — A correlation?

Summary In a survey of 239 populations ofEpilobium representing 17 taxa the following flavonol glycosides were found: myricetin 3-O-arabinoside; 3-O-glucoside; 3-O-rhamnoside; quercetin 3-O-arabinoside; 3-O-glucoside; 3-O-diglucoside; 3-O-rhamnoside; kaempferol 3-O-glucoside; and 3-O-rhamnoside. A correlation appears to exist between seed coat sculpturing as determined in a previous study using SEM techniques, and the flavonoid profiles.Acknowledgments. This study was supported in part by NSERC of Canada and The Boreal Institute for Northern Studies.     

New norsesquiterpene aldehyde and sesquiterpene hemiacetal from the seed ofPolygonum hydropiper

Summary A new norsesquiterpene aldehyde, polygonal and a new sesquiterpene hemiacetal, isodrimeninol having drimane skeleton have been isolated from the seed ofPolygonum hydropiper, and their structures have been established to be1 and5. Polygonal showed pungency and plant growth inhibitory activity.