scholarly journals Pollen Tube Growth and Double Fertilization in Camellia oleifera

2015 ◽  
Vol 140 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Chao Gao ◽  
Deyi Yuan ◽  
Ya Yang ◽  
Bifang Wang ◽  
Dongming Liu ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Edible Oils ◽  
Embryo Sac ◽  
Male Gamete ◽  
Polar Nucleus ◽  
Tube Growth ◽  
Camellia Oleifera ◽  
Double Fertilization ◽  
Primary Endosperm Nucleus

Camellia oleifera is an important plant species that produces edible oils. Understanding the double fertilization of this plant is critical for studies concerning crossbreeding, self-incompatibility, and the biological mechanisms underlying hybridization. We aimed to characterize pollen tube growth and double fertilization in C. oleifera. The female and male parent cultivars (Huashuo and Xianglin XLC15, respectively) were used for artificial pollination. Growth of the pollen tube in the style, ovary, and ovule from pollination to fertilization and the cytological characteristics of female and male gamete fusion during double fertilization were observed using fluorescence and scanning electron microscopy (SEM). Numerous pollen grains germinated 2 to 4 hours after pollination. The pollen tubes entered the interspaces between the papillar cells, grew along the stylar canal, and aggregated at the one-third site of the style. They grew in the gradually narrowing stylar canal, entering the locule. The tubes turned 90° and entered the embryo sac through the micropyle; subsequently, they entered a degenerated synergid, where the spermatids were released. One sperm nucleus fused with the polar nucleus, forming the primary endosperm nucleus, whereas the other sperm fused with the egg, forming the zygote. The polar nucleus was fertilized earlier than the egg. Double fertilization of C. oleifera is characterized as pre-mitotic gametogony. The current results lay a theoretical foundation for studies concerning the crossbreeding and embryology of C. oleifera and provide fundamental data concerning the reproductive biology of the genus Camellia.

scholarly journals Paving the Way for Fertilization: The Role of the Transmitting Tract

2021 ◽  
Vol 22 (5) ◽  
pp. 2603
Author(s):  
Ana Marta Pereira ◽  
Diana Moreira ◽  
Sílvia Coimbra ◽  
Simona Masiero
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Current Knowledge ◽  
Embryo Sac ◽  
Tube Growth ◽  
Signaling Cascades ◽  
Secretory Cells ◽  
Transmitting Tract ◽  
Specialized Tissue

Angiosperm reproduction relies on the precise growth of the pollen tube through different pistil tissues carrying two sperm cells into the ovules’ embryo sac, where they fuse with the egg and the central cell to accomplish double fertilization and ultimately initiate seed development. A network of intrinsic and tightly regulated communication and signaling cascades, which mediate continuous interactions between the pollen tube and the sporophytic and gametophytic female tissues, ensures the fast and meticulous growth of pollen tubes along the pistil, until it reaches the ovule embryo sac. Most of the pollen tube growth occurs in a specialized tissue—the transmitting tract—connecting the stigma, the style, and the ovary. This tissue is composed of highly secretory cells responsible for producing an extensive extracellular matrix. This multifaceted matrix is proposed to support and provide nutrition and adhesion for pollen tube growth and guidance. Insights pertaining to the mechanisms that underlie these processes remain sparse due to the difficulty of accessing and manipulating the female sporophytic tissues enclosed in the pistil. Here, we summarize the current knowledge on this key step of reproduction in flowering plants with special emphasis on the female transmitting tract tissue.

scholarly journals Dynamics of pollen tube growth and embryo sac development in Pozna Plava plum cultivar related to fruit set

2017 ◽  
Author(s):  
Milena Đorđević ◽  
Radosav Cerović ◽  
Sanja Radičević ◽  
Dragan Nikolić ◽  
Nebojša Milošević ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Fruit Set ◽  
Embryo Sac ◽  
Tube Growth ◽  
Parameter Study ◽  
Ovule Development ◽  
Reproductive Process ◽  
Effective Period ◽  
The Impact

AbstractA newly released, late ripening plum cultivar Pozna Plava sets fruit poorly, although it produces high quality fruit. This study aimed to evaluate which factors in the reproductive process could be related to the lack of fruit set. In two consecutive years, establishment of a suitable polleniser and the stage of ovule development at anthesis as well as initial and final fruit set have been studied. In addition to this, the impact made by temperature fluctuations on the interaction between male gametophytes and female sporophytes was also analysed. Growth of the pollen tubes in the style and penetration into the nucellus as well as fruit set were more effective in cross-pollination than in open and self-pollination. A relative delay in ovule development was observed, and most ovules had an embryo sac with eight nuclei. Considering the results of the quantitiative parameter study of pollen tube growth in the ovary as well as the results of the stage of ovule development, a conclusion can be made that this cultivar is characterised by an extremely short effective period of pollination.

Floral Anatomy and Pollen Tube Growth in the Quandong (Santalum acuminatum (R. Br.) A. DC.)

1982 ◽  
Vol 30 (6) ◽  
pp. 601 ◽  
Author(s):  
M Sedgley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Floral Anatomy ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
The Other ◽  
Tube Growth ◽  
Scanning Electron

Floral anatomy and pollen tube growth in the quandong were studied using light and scanning electron microscopy. The flowers had four perianth lobes and four stamens whose anthers dehisced by longitudinal slits. The pollen became caught in long unicellular hairs adjacent to the anthers. The central disc secreted nectar through raised stomata. The stigma papilla cells had a cuticle with a rough surface overlying thick PAS-positive walls. The half-inferior ovary normally contained two ovules. The embryo sac extended beyond the ovule at the micropylar end and into the placenta at the chalazal end. Half of the ovaries observed at both anthesis and 4 days following anthesis had no embryo sacs and the other half had one embryo sac. Occasional ovaries had two embryo sacs and some underdeveloped embryo sacs were observed that did not extend beyond the ovule or into the placenta. Pollen tubes had reached the ovary by 1 day following pollination and the stigma was receptive for 8 days following anthesis. Only half of the pistils had pollen tubes in the ovary. Unpollinated flowers had no pollen tube growth in the pistil.

scholarly journals Pollen tube growth through nucellus into embryo sac of Spinacia - an ultrastructural investigation

2014 ◽  
Vol 50 (1-2) ◽  
pp. 191-193 ◽  
Author(s):  
H. J. Wilms
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Ultrastructural Investigation ◽  
Nucellar Tissue

The micropylar parts of nucellus and embryo sac were studied in relation to pollen tube growth and its entrance into the embryo sac. The initially homogeneous walls of the cells of the conductive nucellar tissue disintegrate at the middle lamellae region. Pollen tubes pierce the nucellar cuticle and continue their growth into the nucellus intercellularly. Subsequently they can follow various pathways to reach the FA of the degenerated synergid. The penetration into this synergid, and the discharge of the tube contents are described and discussed.

scholarly journals Pollen Tube Growth and Embryo Sac Development in ‘Pozna Plava’ Plum Cultivar Related to Fruit Set

2019 ◽  
Vol 61 (4) ◽  
pp. 313-322
Author(s):  
Milena Đorđević ◽  
Radosav Cerović ◽  
Sanja Radičević ◽  
Dragan Nikolić ◽  
Nebojša Milošević ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Fruit Set ◽  
Embryo Sac ◽  
Tube Growth ◽  
Embryo Sac Development

Effect of Heat Stress During Floral Development on Pollen Tube Growth and Ovary Anatomy in Wheat (Triticum aestivum L.)

1983 ◽  
Vol 10 (2) ◽  
pp. 137 ◽  
Author(s):  
HS Saini ◽  
M Sedgley ◽  
D Aspinall
Keyword(s):  
Heat Stress ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Triticum Aestivum L ◽  
Tube Growth ◽  
Ovary Development ◽  
Abnormal Growth ◽  
Full Complement

Wheat plants (cv. Gabo) otherwise grown at 20°C were subjected to a temperature of 30°C for 3 days at the onset of meiosis in the anthers. Control plants were maintained at 20°C throughout development. Serial sections through the heat-stressed ovaries just prior to anthesis showed that a third contained abnormal embryo sacs. Abnormalities ranged from the complete absence of an embryo sac accompanied by reduced nucellus development, to small embryo sacs that contained the full complement of cells. No abnormalities were observed in control ovaries. Following pollination with fertile pollen, heat-stressed stigmas had similar numbers of germinated pollen grains to non-stressed controls but there were fewer tubes reaching the ovary. In 7% of the stressed pistils, no pollen tube reached the ovary. Callose was deposited in some of the inhibited pollen grains and tubes that showed abnormal growth. It is concluded that heat stress during meiosis in wheat can reduce yield by causing abnormal ovary development, which results in reduced pollen tube growth and seed set.

scholarly journals Ovary Signals for Pollen Tube Guidance in Chalazogamous Mangifera indica L.

2021 ◽  
Vol 11 ◽  
Author(s):  
Jorge Lora ◽  
Veronica Perez ◽  
Maria Herrero ◽  
Jose I. Hormaza
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Mangifera Indica ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Transmitting Tissue ◽  
Egg Apparatus ◽  
Pollen Tube Elongation

Most flowering plants show porogamy in which the pollen tubes reach the egg apparatus through the micropyle. However, several species show chalazogamy, an unusual pollen tube growth, in which the pollen tubes reach the embryo sac through the chalaza. While ovary signals for pollen tube growth and guidance have been extensively studied in porogamous species, few studies have addressed the process in chalazogamous species such as mango (Mangifera indica L.), one of the five most important fruit crops worldwide in terms of production. In this study, we characterize pollen–pistil interaction in mango, paying special attention to three key players known to be involved in the directional pollen tube growth of porogamous species such as starch, arabinogalactan proteins (AGPs), and γ-aminobutyric acid (GABA). Starch grains were observed in the style and in the ponticulus at anthesis, but their number decreased 1 day after anthesis. AGPs, revealed by JIM8 and JIM13 antibodies, were homogenously observed in the style and ovary, but were more conspicuous in the nucellus around the egg apparatus. GABA, revealed by anti-GABA antibodies, was specifically observed in the transmitting tissue, including the ponticulus. Moreover, GABA was shown to stimulate in vitro mango pollen tube elongation. The results support the heterotrophic growth of mango pollen tubes in the style at the expense of starch, similarly to the observations in porogamous species. However, unlike porogamous species, the micropyle of mango does not show high levels of GABA and starch, although they were observed in the ponticulus and could play a role in supporting the unusual pollen tube growth in chalazogamous species.

Inhibition of Pollen Tube Growth by Diffusate and Extract of Grape Pistils

1989 ◽  
Vol 58 (3) ◽  
pp. 515-521 ◽  
Author(s):  
Goro OKAMOTO ◽  
Ikuo SHIBUYA ◽  
Miwa FURUICHI ◽  
Kazuo SHIMAMURA
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Tube Growth
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