Determination of Sex Expression in Cycads

2016 ◽  
pp. 126-140 ◽  
Keyword(s):  
Sex Expression

scholarly journals Brassinosteriod-induced Femaleness in Cucumber and Relationship to Ethylene Production

HortScience ◽  
2005 ◽  
Vol 40 (6) ◽  
pp. 1763-1767 ◽  
Author(s):  
Ekaterina Papadopoulou ◽  
Rebecca Grumet
Keyword(s):  
Ethylene Production ◽  
Female Flower ◽  
Sex Expression ◽  
Bisexual Flower ◽  
Flower Production ◽  
Total Female ◽  
The Difference ◽  
Male Flowers ◽  
Cucurbitaceae Family

The Cucurbitaceae family is noted for a diversity of sex expression phenotypes. Typically, a phase of male flowers precedes either female or bisexual flower production. Sex determination of individual flowers is regulated by a combination of genetic, environmental, and hormonal factors. Ethylene, auxins, and gibberellins have all been shown to influence flower sex expression in cucurbits. Ethylene, which promotes femaleness, plays a predominant role. In this study, we tested whether brassinosteroids (BR), a more recently identified class of plant hormones, also influences cucurbit sex expression. Applied epi-brassinolide (epi-BL) caused a significant decrease in time of appearance of the first female flower on monoecious cucumber plants, and increased total female flowers on the main stem. Increasing concentrations had a stronger effect. Of the three species tested, cucumber, melon and zucchini, cucumber was the most responsive to BR. Application of epi-BL also caused an increase in ethylene production by cucumber and zucchini seedlings, suggesting that the BR effect may be mediated by ethylene. To investigate the possible relationship between BR and ethylene on sex expression, we identified the concentration of ethephon (5 ppm) that caused an increase in ethylene production comparable to that induced by 10 μm epi-BL (approximately two-fold). Treatment with 5 ppm ethephon was sufficient to increase femaleness of cucumber plants, but not zucchini plants, suggesting that the difference in response to epi-BL treatment may reflect differences in sensitivity to ethylene. Collectively, our results indicate that application of brassinosteroids to cucumber cause earlier and increased female flower production, and that the effects may be mediated, at least in part, by brassinosteroid-induced production of ethylene.

Reproduction in Heteropogon contortus. I. Photoperiodic effects on flowering and sex expression

1968 ◽  
Vol 19 (6) ◽  
pp. 869 ◽  
Author(s):  
JC Tothill ◽  
RB Knox
Keyword(s):  
Sex Expression ◽  
Population Heterogeneity ◽  
Day Length ◽  
Night Temperature ◽  
Late Flowering ◽  
Heteropogon Contortus ◽  
Short Day ◽  
African Populations ◽  
Flowering Behaviour

The flowering behaviour of selected Australian and African populations of Heteropogon contortus in response to a range of photoperiods was assessed in the Canberra phytotron (CERES) under a 30/25°C day/night temperature regime. Photoperiods comprised 8 hr of natural light supplemented with low intensity incandescent illumination to give a range between 10 and 18 hr in each photocycle. The patterns of response showed H. contortus to be a short-day plant. Lines from both Australian and African populations originating from lower latitudes, and late-flowering when grown in a grass garden, flowered only in photoperiods shorter than 12 hr, remaining vegetative at longer day lengths. These were qualitative short-day plants. In contrast, the early-flowering lines showed either a qualitative or a quantitative short-day response; the latter flowered in all photoperiods but more rapidly at shorter day lengths. The nature of the early- and late-flowering behaviour is explained on the basis of the short-day responses and climatic adaptation. Since the inflorescences are polygamous, a sex ratio was calculated for all inflorescences formed by using the ratio of number of male+male spikelet pairs v. the number of female+male spikelet pairs. Increasing the photoperiod resulted in inflorescences containing more male spikelets and fewer awned female spikelets. From this it appears that day length exerts some influence over the determination of sex, and thus of seed production, in H. contortus. Versatility of this kind may well have adaptive significance depending on the breeding system in that it can partially control population heterogeneity and thus be of phytogeographic significance.

scholarly journals The effect of ethepon treatment on the formation of flower in melon (Cucumis melo L.)

2018 ◽  
Vol 1 ◽  
pp. 00002
Author(s):  
Budi Setiadi Daryono ◽  
Eko Prasetya ◽  
Sumarlina Sumarlina ◽  
Dian Sartika ◽  
Aprilia Sufi Subiastuti
Keyword(s):  
Sex Expression ◽  
Fruit Production ◽  
Hermaphrodite Flower ◽  
Significance Level ◽  
Randomized Design ◽  
Plant Chemical ◽  
Monoecious Plant ◽  
Male Flowers ◽  
Cucumis Melo L

<p class="Abstract">Melon is a potential horticultural crop which the production is increased significantly each year in Indonesia. However, a melon plant that has been widely developed in Indonesia faced a problem due to the high tropical temperature that affected the fall of flower causing failure in fruit production. In addition, the variation of sex expression in melon flower is important for genetic analysis and breeding programs. Ethepon is one of plant chemical growth regulator that is known to change the sex expression of the plant by increasing the number of female flower in monoecious plant especially Cucurbitaceae. This research aimed to analyze the effect of ethepon treatment on the sex determination of melon flower. This study was conducted by 3 stages treatment of ethepon during March – July 2014, namely when 2, 5, and 7 weeks after planting. Split-plot design has been used with the main plots were arranged in a completely randomized design by cultivating different melon cultivars i.e: Melodi Gama 1, Melodi Gama 3, Bartek, and PI 371795. The data were analyzed by F-test and Duncan Multiple Range Test (DMRT) with significance level at 5 % using software SAS 9.3. The result showed that ethepon treatment affected the formation of melon flower by increasing the number of female or hermaphrodite flower and decreasing the number of male flowers, especially in the concentration of 75 ppm and 100 ppm but with different responses by different cultivar.&nbsp;<o:p></o:p></p>

scholarly journals 230 MOLECULAR MARKERS FOR EARLY DETERMINATION OF SEX OF PISTACHIO SEEDLINGS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 462d-462
Author(s):  
J.I. Hormaza ◽  
L. Dollo ◽  
V.S. Polito
Keyword(s):  
Molecular Markers ◽  
Random Amplified Polymorphic Dna ◽  
Dna Amplification ◽  
Sex Expression ◽  
Pistacia Vera ◽  
Dioecious Species ◽  
Reliable Marker ◽  
The Relationship ◽  
Made In

The Random Amplified Polymorphic DNA (RAPD) technique was used to develop molecular markers linked to sex expression in Pistacia vera, a dioecious species. Progenies from two female parents (`Lassen' and `Kerman') pollinated by a common male parent (`Peters') were studied. Two bulks of DNA were made in each cross, one from males and one from females. DNA was extracted from each bulked sample as well as from each of the contributing individuals and from 14 additional P. vera cultivars. Twelve hundred decamer oligonucleotide primers were used to perform DNA amplification on the bulk DNA. This analysis led to the identification of one primer (OPO08) that produces a 945 bp. amplification band present only in females and absent in males. The relationship between band presence and female sex expression was conserved in every individual obtained from the two crosses and in 14 cultivars unrelated to the crosses. This band, which we propose is tightly linked to the gene(s) controlling sex determination, provides a reliable marker for sex of pistachio seedlings and should be a useful tool in pistachio breeding.

scholarly journals (214) Brassinosteroid-induced Femaleness in Cucumber and Relationship to Ethylene Production

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1057C-1057
Author(s):  
Ekaterina Papadopoulou ◽  
Rebecca Grumet
Keyword(s):  
Ethylene Production ◽  
Female Flower ◽  
Sex Expression ◽  
Predominant Role ◽  
Flower Production ◽  
Total Female ◽  
The Difference ◽  
Male Flowers ◽  
Female Flowers

The cucurbit family is noted for diversity in sex expression phenotypes. Typically, a phase of male flowers precedes the appearance of female or hermaphrodite flowers. Sex determination of individual flowers is regulated by genetic, environmental, and hormonal factors. Ethylene, auxins, and gibberellins all influence flower sex, with ethylene, which promotes femaleness, playing a predominant role. In this study, we tested whether brassinosteroids, a more recently identified class of plant hormones, also influence cucurbit sex expression. Applied epi-brassinolide (epi-BL) caused a significant decrease in time of appearance of the first female flower on monoecious cucumber plants, and increased total female flowers on the main stem. Increasing concentrations had a stronger effect. Of the three species tested, cucumber, melon, and zucchini, cucumber was the most responsive. Application of epi-BL also caused an increase in ethylene production by cucumber and zucchini seedlings, suggesting that the BR effect may be mediated by ethylene. To investigate the possible relationship between BR and ethylene on sex expression, we identified the concentration of ethephon (5 ppm) that caused an increase in ethylene production comparable to that induced by 10 μm epi-BL (about two-fold). Treatment with 5 ppm ethephon was sufficient to increase femaleness of cucumber plants, but not zucchini plants, suggesting that the difference in response to epi-BL may reflect differences in sensitivity to ethylene. Collectively, our results indicate that application of brassinosteroids to cucumber cause earlier and increased female flower production, and that the effects may be mediated, at least in part, by brassinosteroid-induced increased production of ethylene.

scholarly journals Seleksi Marka SCAR untuk Identifikasi Dini Jenis Kelamin Tanaman Pepaya (The Selection of SCAR Markers for Early Sex Identification of Papaya)

2020 ◽  
Vol 30 (1) ◽  
pp. 1
Author(s):  
NFN Noflindawati ◽  
Aswaldi Anwar ◽  
Agus Sutanto ◽  
NFN Yusniwati
Keyword(s):  
Sex Expression ◽  
Scar Markers ◽  
Tropical Fruit ◽  
Sequence Characterization ◽  
Sequence Characterized Amplified Region ◽  
Plant Sex ◽  
Scar Primers ◽  
Selection Of ◽  
Physiological Characters

<p>Identifikasi dini terhadap jenis kelamin tanaman pepaya merupakan hal penting yang dapat membantu petani dalam budidaya tanaman pepaya. Identifikasi kelamin pepaya berdasarkan marka morfologi dan fisiologi telah dilakukan, namun beberapa hasilnya masih bias karena faktor lingkungan. Identifikasi kelamin tanaman pepaya menggunakan marka molekuler bisa lebih cepat dan akurat. Penelitian tersebut telah banyak dilakukan, salah satu di antaranya adalah marka berbasis sequence characterized amplified region (SCAR) dan beberapa primer SCAR telah dihasilkan untuk identifikasi kelamin pepaya. Penelitian bertujuan untuk menyeleksi primer SCAR yang efektif dalam mengidentifikasi seks tanaman pepaya. Penelitian  dilakukan pada bulan November 2018 sampai Juni 2019 di Laboratorium Molekuler dan Uji Mutu Kebun Percobaan Sumani Balai Penelitian Tanaman Buah Tropika di Solok. Primer SCAR yang diseleksi adalah W11,T12, PKBT5, Napf2, dan SDp. Tanaman referensi sebagai sampel umur 11–12 bulan  adalah tanaman betina, jantan, dan  hermaprodit masing-masing lima tanaman dari pepaya lokal dan Merah Delima. Hasil penelitian menunjukkan bahwa lima primer SCAR yang diuji  hanya dapat membedakan tanaman betina dengan tanaman jantan dan hermaprodit tetapi belum dapat membedakan antara tanaman jantan dengan hermaprodit. Konsistensi pola amplifikasi dihasilkan dari primer SCAR W11, Napf2, dan T12 dengan posisi 800 bp. Primer SCAR W11, Napf2, dan T12 selanjutnya dapat digunakan sebagai marka untuk identifikasi kelamin tanaman betina dengan tanaman jantan dan hermaprodit.</p><p><strong>Keywords</strong></p><p>SCAR; Identifikasi; Pepaya; Jantan, Hermaprodit </p><p><strong>Abstract</strong></p><p>The determination of sex expression of papaya plants is important to farmers in its cultivation. The identification of papaya plant sex based on morphological and physiological characters have been previously carried out, however, the results were still biased due to environmental factors. Many studies have been carried out to identify this plant sex, such as the use of molecular and SCAR markers, based on sequence characterization on amplified regions. This research aims to select the SCAR primers that are effective in identifying papaya plant sex. The study was conducted from November 2018 to June 2019, at Laboratory of Molecular and Quality Testing of the Indonesian Tropical Fruit Research Institute in Solok. The selected SCAR primers were W11, T12, PKBT5, Napf2, and SDp, using a total of five female, male, and hermaphrodite plants are reference aged 11–12 month from local papaya and cv. Merah Delima. The five SCAR primers tested were only able to differentiate females from male and hermaphrodite plants. The consistency of the amplification pattern was obtained from the SCAR W11, T12, and Napf2 primers at 800 bp. In conclusion, SCAR W11, Napf2, and T12 primers are used as markers to distinguish female plants from male and hermaphrodite.</p>

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

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