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

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.

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 249
Author(s):  
Weimiao Liu ◽  
Liai Xu ◽  
Hui Lin ◽  
Jiashu Cao

The growth of plant cells is inseparable from relaxation and expansion of cell walls. Expansins are a class of cell wall binding proteins, which play important roles in the relaxation of cell walls. Although there are many members in expansin gene family, the functions of most expansin genes in plant growth and development are still poorly understood. In this study, the functions of two expansin genes, AtEXPA4 and AtEXPB5 were characterized in Arabidopsis thaliana. AtEXPA4 and AtEXPB5 displayed consistent expression patterns in mature pollen grains and pollen tubes, but AtEXPA4 also showed a high expression level in primary roots. Two single mutants, atexpa4 and atexpb5, showed normal reproductive development, whereas atexpa4atexpb5 double mutant was defective in pollen tube growth. Moreover, AtEXPA4 overexpression enhanced primary root elongation, on the contrary, knocking out AtEXPA4 made the growth of primary root slower. Our results indicated that AtEXPA4 and AtEXPB5 were redundantly involved in pollen tube growth and AtEXPA4 was required for primary root elongation.


2021 ◽  
Vol 22 (5) ◽  
pp. 2603
Author(s):  
Ana Marta Pereira ◽  
Diana Moreira ◽  
Sílvia Coimbra ◽  
Simona Masiero

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.


Author(s):  
Laetitia Poidevin ◽  
Javier Forment ◽  
Dilek Unal ◽  
Alejandro Ferrando

ABSTRACTPlant reproduction is one key biological process very sensitive to heat stress and, as a consequence, enhanced global warming poses serious threats to food security worldwide. In this work we have used a high-resolution ribosome profiling technology to study how heat affects both the transcriptome and the translatome of Arabidopsis thaliana pollen germinated in vitro. Overall, a high correlation between transcriptional and translational responses to high temperature was found, but specific regulations at the translational level were also present. We show that bona fide heat shock genes are induced by high temperature indicating that in vitro germinated pollen is a suitable system to understand the molecular basis of heat responses. Concurrently heat induced significant down-regulation of key membrane transporters required for pollen tube growth, thus uncovering heat-sensitive targets. We also found that a large subset of the heat-repressed transporters is specifically up-regulated, in a coordinated manner, with canonical heat-shock genes in pollen tubes grown in vitro and semi in vivo, based on published transcriptomes from Arabidopsis thaliana. Ribosome footprints were also detected in gene sequences annotated as non-coding, highlighting the potential for novel translatable genes and translational dynamics.


2014 ◽  
Vol 65 (1-2) ◽  
pp. 101-105 ◽  
Author(s):  
Renata Śnieżko ◽  
Krystyna Winiarczyk

After selfpollination of <em>Sinapis alba</em> L. pollen tubes growth is inhibited on the stigma. The pollen grains germinate 3-4 hours after pollination. The pollen give rise to one or more pollen tubes. They grow along the papillae. In the place of contact between the papilla and pollen tube the pellicula is digested. Then the direction of pollen tube growth changes completely. Pollen tubes grow back on the exine of their own pollen grain, or turn into the air. The pollen tubes growth was inhibited in 6-8 hours after selfpollination. After crosspollination usually there is no incompatibility reaction.


2008 ◽  
Vol 35 (2) ◽  
pp. 152 ◽  
Author(s):  
Kanjana Luangsuwalai ◽  
Saichol Ketsa ◽  
Apinya Wisutiamonkul ◽  
Wouter G. van Doorn

Dendrobium flowers, pollinated with pollinia from individuals of the same cultivar or other cultivars, usually show rapid post-pollination effects such as floral epinasty, a change in flower colour and early perianth senescence. However, pollination with the pollinia of cv. Karen or cv. Kenny flowers did not produce these effects. We compared these two cultivars with cvv. Pompadour, Willie and Sakura, and tested the hypotheses that the differences were related to levels of 1-aminocyclopropane-1-carboxylic acid (ACC) in the pollinia, ethylene production by the pollinated flower, pollen germination, or pollen tube growth. The pollinia of cvv. Karen and Kenny contained as much ACC as the pollinia of cv. Pompadour, but less than the pollinia of cvv. Willie and Sakura. Ethylene production after pollination with cvv. Karen and Kenny pollinia was much lower than after pollination with pollinia from the other cultivars tested. The pollen grains showed normal germination, but cvv. Karen and Kenny pollen grains exhibited much less tube growth than those of the other cultivars. Pollen tube growth in cv. Pompadour was positively affected by ethylene. Ethylene was required and sufficient for the induction of epinasty, rapid perianth colour changes and early perianth senescence, very similar to the changes after pollination. The absence of these effects after pollination with cvv. Kenny and Karen seems to be due to the low ethylene production induced by the pollinia of these cultivars. This low ethylene production could not be accounted for by the ACC content in the pollinia of cvv. Kenny and Karen.


2017 ◽  
Author(s):  
Milena Đorđević ◽  
Radosav Cerović ◽  
Sanja Radičević ◽  
Dragan Nikolić ◽  
Nebojša Milošević ◽  
...  

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.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260576
Author(s):  
Massaine Bandeira e Sousa ◽  
Luciano Rogerio Braatz de Andrade ◽  
Everton Hilo de Souza ◽  
Alfredo Augusto Cunha Alves ◽  
Eder Jorge de Oliveira

Cassava breeding is hampered by high flower abortion rates that prevent efficient recombination among promising clones. To better understand the factors causing flower abortion and propose strategies to overcome them, we 1) analyzed the reproductive barriers to intraspecific crossing, 2) evaluated pollen-pistil interactions to maximize hand pollination efficiency, and 3) identified the population structure of elite parental clones. From 2016 to 2018, the abortion and fertilization rates of 5,748 hand crossings involving 91 parents and 157 progenies were estimated. We used 16,300 single nucleotide polymorphism markers to study the parents’ population structure via discriminant analysis of principal components, and three clusters were identified. To test for male and female effects, we used a mixed model in which the environment (month and year) was fixed, while female and male (nested to female) were random effects. Regardless of the population structure, significant parental effects were identified for abortion and fertilization rates, suggesting the existence of reproductive barriers among certain cassava clones. Matching ability between cassava parents was significant for pollen grains that adhered to the stigma surface, germinated pollen grains, and the number of fertilized ovules. Non-additive genetic effects were important to the inheritance of these traits. Pollen viability and pollen-pistil interactions in cross- and self-pollination were also investigated to characterize pollen-stigma compatibility. Various events related to pollen tube growth dynamics indicated fertilization abnormalities. These abnormalities included the reticulated deposition of callose in the pollen tube, pollen tube growth cessation in a specific region of the stylet, and low pollen grain germination rate. Generally, pollen viability and stigma receptivity varied depending on the clone and flowering stage and were lost during flowering. This study provides novel insights into cassava reproduction that can assist in practical crossing and maximize the recombination of contrasting clones.


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