Seed Ontogeny and Nonstructural Carbohydrates of Cycas micronesica Megagametophyte Tissue

in HortScience

The profile of nonstructural carbohydrates (NSC) was quantified to determine sugar and starch relationships of megagametophyte tissue during Cycas micronesica K.D. Hill seed ontogeny. Field work occurred in northern Guam where megastrobili were marked and dated as they emerged from stem apices of plants in a natural population. Seeds were harvested beginning 6 months after megastrobili emergence and continuing until 28 months, and gametophyte tissue was separated from the remainder of each seed. Carbohydrates within lyophilized gametophyte tissue were quantified by high-pressure liquid chromatography. The levels of glucose and fructose declined from a high at 6 months to a homeostasis at 11 months, and the levels of sucrose similarly declined from 6 months to a homeostasis at ≈14 months. Starch content exceeded sugar content and increased from 6 months to reach a homeostasis at ≈18 months. Maltose was not detected in any sample. Stoichiometric quotients changed dramatically until ≈14 months, when they became fairly stable until 28 months. Starch concentration was ≈5-fold greater than sugar concentration at 6 months, and increased to ≈15-fold greater than sugar concentration by 28 months. Total NSC in mature megagametophytes was almost 70% on a dry weight basis. Our results are in agreement with the biological function of this haploid tissue, as copious carbohydrate resources are readily available to support embryo and seedling growth.

Contributor Notes

We thank Gil Cruz for help with field work. Support for analytical work provided by the U.S. Department of the Navy through N40192-12-2-8000 and N40192-13-2-8003, administered by Naval Facilities Engineering Command Marianas, Guam.

Corresponding author. E-mail: thomas.marler@gmail.com.

Article Sections

Article Figures

  • View in gallery

    General appearance of Cycas micronesica seeds from emergence to maturity. (A) Megastrobili phenotype at 6 weeks following emergence. (B) Seed at 6 months. Gametophyte (g) and flotation (f) tissues are labeled. (C) Seed at 11 months. (D) Seed at 14 months. (E) Seed at 20 months. (F) Seed at 28 months.

  • View in gallery

    Cycas micronesica seed megagametophyte fructose, glucose, sucrose, and starch concentration as influenced by seed age. Markers are mean ± se, n = 6. Fructose: If x < 11.5, then y = 40.55 – 2.53x; r2 = 0.99; P = 0.05, glucose: If x < 11, then y = 30.71 – 1.61x; r2 = 0.99; P = 0.02, sucrose: If x < 14, then y = 61.98 – 3.07x; r2 = 0.96; P = 0.02, starch: If x < 18, then y = 253.75 + 22.60x; r2 = 0.99; P < 0.001.

  • View in gallery

    Stoichiometric relations of pairs of nonstructural carbohydrate pools for Cycas micronesica megagametophytes, defined as quotients and as influenced by seed age. Markers are mean values, n = 6.

Article References

  • BrennerE.D.StevensonD.W.TwiggR.W.2003Cycads: Evolutionary innovations and the role of plant-derived neurotoxinsTrends Plant Sci.8446452

    • Search Google Scholar
    • Export Citation
  • BrummittN.A.BachmanS.P.Griffiths-LeeJ.LutzM.MoatJ.F.FarjonA.DonaldsonJ.S.Hilton-TaylorC.MeagherT.R.AlbuquerqueS.AletrariE.AndrewsA.K.AtchisonG.BalochE.BarlozziniB.BrunazziA.CarreteroJ.CelestiM.ChadburnH.CianfoniE.CockelC.ColdwellV.ConcettiB.ContuS.CrookV.DysonP.GardinerL.GhanimN.GreeneH.GroomA.HarkerR.HopkinsD.KhelaS.Lakeman-FraserP.LindonH.LockwoodH.LoftusC.LombriciD.Lopez-PovedaL.LyonJ.Malcolm-TompkinsP.McGregorK.MorenoL.MurrayL.NazarK.PowerE.TuijtelaarsM.Q.SalterR.SegrottR.ThackerH.ThomasL.J.TingvollS.WatkinsonG.WojtaszekovaK.Nic LughadhaE.M.2015Green plants in the red: A baseline global assessment for the IUCN sampled Red List Index for plantsPLoS One10E0135152

    • Search Google Scholar
    • Export Citation
  • CairnsA.J.PollockC.J.1988Fructan biosynthesis in excised leaves of Lolium temulentumNew Phytol.7212691280

  • CalonjeC.HusbyC.CalonjeM.2010Germination and early seedling growth of rare Zamia spp. in organic and inorganic substrates: Advancing ex situ conservation horticultureHortScience45679683

    • Search Google Scholar
    • Export Citation
  • CalonjeM.KayJ.GriffithM.P.2011Propagation of cycad collections from seed: Applied reproductive biology for conservationSibbaldia97796

    • Search Google Scholar
    • Export Citation
  • ChapinF.S.SchulzeE.-D.MooneyH.A.1990The ecology and economics of storage in plantsAnnu. Rev. Ecol. Syst.21423447

  • DonaldsonJ.S.(ed.).2003Cycads. Status survey and conservation action plan. IUCN/SSC Cycad Specialist Group. IUCN Gland Switzerland and Cambridge UK

  • FragniereY.BétriseyS.CardinauxL.StoffelM.KozlowskiG.2015Fighting their last stand? A global analysis of the distribution and conservation status of gymnospermsJ. Biogeogr.42809820

    • Search Google Scholar
    • Export Citation
  • HaywardP.KuwaharaS.2012Sotetsu heritage: Cycads, sustenance and cultural landscapes in the Amami IslandsThe Australasian-Pacific J. Regional Food Studies22646

    • Search Google Scholar
    • Export Citation
  • HillK.D.1994The Cycas rumphii complex (Cycadaceae) in New Guinea and the Western PacificAustral. Syst. Bot.7543567

  • LeducS.N.M.SilvaJ.P.N.GasparM.BarbedoC.J.Figueiredo-RibeiroR.D.C.L.2012Non-structural carbohydrates of immature seeds of Caesalpinia echinata (Leguminosae) are involved in the induction of desiccation toleranceAustral. J. Bot.604248

    • Search Google Scholar
    • Export Citation
  • LehnerA.BaillyC.FlechelB.PoelsP.CômeD.CorbineauF.2006Changes in wheat seed germination ability, soluble carbohydrates and antioxidant enzyme activities in the embryo during the desiccation phase of maturationJ. Cereal Sci.43175182

    • Search Google Scholar
    • Export Citation
  • LinT.-P.HuangN.-H.1994The relationship between carbohydrate composition of some tree seeds and their longevityJ. Expt. Bot.4512891294

  • MarlerT.E.DongolN.2011Models to describe Cycas micronesica leaf and strobili developmentHortScience4613331337

  • MarlerT.E.LawrenceJ.H.2012Demography of Cycas micronesica on Guam following introduction of the armoured scale Aulacaspis yasumatsuiJ. Trop. Ecol.28233242

    • Search Google Scholar
    • Export Citation
  • MarlerT.E.LindströmA.J.2014Free sugar profile in cycadsFront. Plant Sci.5526

  • MarlerT.E.LindströmA.J.2015Carbohydrates, pollinators, and cycadsCommun. Integr. Biol.8E1017162

  • Müller-RöberB.T.KossmanJ.HannahL.C.WillmitzerL.SonnewaldU.1990ADP-glucose pyrophosphorylase genes from potato: Mode of RNA expression and its relation to starch synthesis p. 204–208. In: J.-L. Bonnemain S. Delrot W.J. Lucas and J. Dainty (eds.). Phloem transport and assimilate compartmentation. Ouest Nantes France

  • MurphyV.MooreK.GriffithM.P.HusbyC.2013Improving conservation through cultivation: Nine container substrates influence growth of a rare cycad, Zamia pumila LHortScience4811681172

    • Search Google Scholar
    • Export Citation
  • NorstogK.J.NicholsT.J.1997The biology of the cycads. Cornell University Press Ithaca NY

  • PantD.D.1973Cycas and cycadales. Central Book Depot Allahabad India

  • Sánchez-TinocoM.Y.Ordóñez-BalderasJ.R.EnglemanE.M.2012Starch accumulation in the megagametophyte of Ceratozamia mexicana Brongn. and Zamia furfuracea L.fMem. N. Y. Bot. Gard.106251262

    • Search Google Scholar
    • Export Citation
  • SchloterM.WinklerJ.B.AnejaM.KochN.FleischmannF.PritschK.HellerW.StichS.GramsT.E.GöttleinA.MatyssekR.MunchJ.C.2005Short term effects of ozone on the plant-rhizosphere-bulk soil system of young beech treesPlant Biol.7728736

    • Search Google Scholar
    • Export Citation
  • ThieretJ.W.1958Economic botany of the cycadsEcon. Bot.12341

  • VandecasteeleC.Teulat-MerahB.Morère-Le PavenM.C.LeprinceO.VuL.B.ViauL.LedroitL.PelletierS.PayetN.SatourP.LebrasC.GallardoK.HuguetT.LimamiA.M.ProsperiJ.M.BuitinkJ.2011Quantitative trait loci analysis reveals a correlation between the ratio of sucrose/raffinose family oligosaccharides and seed vigour in Medicago truncatulaPlant Cell Environ.3414731487

    • Search Google Scholar
    • Export Citation
  • Vázquez-TorresM.Sánchez-TinocoM.Y.Alejandre-RosasJ.A.1989Algunos datos etnobotánicos sobre las Zamiaceae (Cycadales) de México (in Spanish)La Ciencia y el Hombre31930

    • Search Google Scholar
    • Export Citation
  • WhitingM.G.1963Toxicity of cycadsEcon. Bot.17271302

  • YoungF.J.1988Soil survey of territory of Guam. United States Department of Agriculture Soil Conservation Service Washington DC

  • U.S. Fish and Wildlife Service (USFWS)2015Endangered and threatened wildlife and plants; Endangered status for 16 species and threatened status for 7 species in Micronesia. Federal Register 80(190):59424–59497

Article Information

Google Scholar

Related Content

Article Metrics

All Time Past Year Past 30 Days
Abstract Views 60 60 2
Full Text Views 79 79 0
PDF Downloads 8 8 0