Biyu hadi

Hirtsinta hatsi cewa fada a kan stigma na ko ta wani hanya, fara germinate. Hatsi ta kumbura, pollen tube aka kafa daga vegetative Kwayoyin. Saboda haka, germination fara. A harsashi karya a thinnest wuri na pollen tube. Daga cikin tip na tube kasaftawa musamman abubuwa. Sun yi laushi yadudduka shafi da kuma stigma.

A tsakiya na generative kuma vegetative Kwayoyin wuce a cikin pollen tube. Generative cell ya raba da kuma siffofin biyu maniyyi. Ta hanyar micropyle (a rami a cikin kwasfa) ovule pollen tube aka shiga cikin amfrayo jakar kwai. Ciki da jakar tube aka karya da kuma da abinda ke ciki zubo.

Sa'an nan Fusion ya auku tare da maniyyi daga daya kwai. Saboda haka, a zygote, baya bada farko iri tayi. Tare da wannan na biyu hade da tsakiyar tsakiya na maniyyi. Wannan take kaiwa ga samuwar na triploid tsakiya mirgina daga baya a triploid endosperm, wanda shi ne na biyu.

All sama tsari ne da ake kira "biyu hadi a cikin flowering shuke-shuke."

Antipodes da synergids (iyakacin duniya nuclei a cikin tayi jakar kwai) bayan kammala aiwatar ake narkar da, da kuma integuments (abũbuwan rufi) samar da zuriya gashi.

Biyu hadi a cikin shuke-shuke da aka gano ta Rasha masanin kimiyya S. Navashin.

A wannan tsari, da tsakiya a cikin tayi jakar kwai ne kullum ya fi girma sosai fiye da da maniyyi tsakiya, wanda aka sa by gano farko Interphase (matsakaici lokaci). A wannan yanayin da kuma siffar na nuclei amfrayo jakar kwai iya bambanta. Alal misali, wasu Asteraceae su iya elongated, wani lokacin tortuous, wadanda ba nucleoli. Kullum, maniyyi aka gabatar a cikin nau'i na taso Interphase nuclei da nucleoli, a wasu lokuta, da ciwon babu bambanci ga tsarin da mace nuclei.

Biyu hadi iya zama na biyu iri daban-daban, dangane da yanayin da ƙungiyar na namiji da mace nuclei.

Saboda haka, a lokacin da tsari na faruwa premitotic nutsewa maniyyi nuclei a cikin mace core, inda despiralization (unwinding) chromosomes. A wannan jam'iyya sets biyu chromosomes a Interphase nuclei yi.

Postmitotic biyu hadi ne wani shigarwa na namiji da mace nuclei, rikewa harsashi a prophase, wanda ƙare kungiyarsu. Ilimi Interphase nuclei, wanda dauke da chromosome sets, ya zo bayan za ta karbi bakuncin mitotic rabo a cikin zygote.

Lokacin da biyu hadi auku a kwai cell Fusion na biyu haploid (dauke da rabin adadin chromosomes) tsakiya, duk da haka diploid zygote tsakiya (tare da cikakken sa na chromosomes).

Dangane da yawan iyakacin duniya nuclei dauke a cikin tsakiyar cell an kafa chromosome yawan endosperm nuclei.

Biyu hadi da inganta harkokin nuni halaye masu mallaka a cikin endosperm na tsaba (matasan) shuka endosperm daga ubanku. Tare da shigar azzakari cikin farji daga cikin jakar kwai tayi 'yan pollen shambura, da tsari ya shafi maniyyi daga farko tube, a cikin wasu shambura maniyyi degenerate. Biyu hadi da biyu ma'ana ne musamman rare.

A lokacin mahaifa da dama da bincike ta amfani da wakilan daban-daban angiosperms (Compositae, Ranunculaceae, Liliaceae) Navashin m endosperm aka tabbatar a matsayin tayi ga jima'i tsari a cikin flowering shuke-shuke. Wannan sabon abu ne halayyar kawai na wakilan da angiosperms Flora.

Ya kamata a lura da cewa aikin Navashin yarda ka bayyana da tambaya akan asalin da endosperm. Illar da hakan daga cikin binciken da masana kimiyya an kara raya.