Search Results

You are looking at 1 - 10 of 15 items for :

  • "ovule longevity" x
Clear All
Free access

Yerko M. Moreno and Anita Nina Miller

Some cultivars of prune (i.e. `Brooks') consistently set good crops while others (i.e. `Italian') are erratic bearers. Fall-applied ethephon increases fruit set. Ovule longevity has been hypothesized to be an important factor in fruit retention. The effects of the cultivar and fall ethephon application on ovule longevity were determined.

Ethephon (0 and 500 mg·l-1) was applied to `Italian' and `Brooks' prune trees at the 50% leaf drop stage. The following spring, flower buds were emasculated and covered to prevent pollination. Ten flowers were sampled every two days from anthesis until 20 days after anthesis (DAA). Flowers were fixed in FAP and ovule longevity determined using fluorescence microscopy. Ovule longevity was longer in `Brooks' than `Italian'. At 20 DAA, all of the `Brooks' flowers still had viable ovules. Only 40% of the `Italian' flowers had viable ovules. The `Italian' flowers excised from ethephon-treated trees had at least one non-senescent ovule at 17 DAA. Ethephon prolonged ovule longevity in `Italian' prune flowers. No effect of ethephon was observed on the ovule longevity of the `Brooks' prune.

Free access

Yerko M. Moreno and Anita Nina Miller

Some cultivars of prune (i.e. `Brooks') consistently set good crops while others (i.e. `Italian') are erratic bearers. Fall-applied ethephon increases fruit set. Ovule longevity has been hypothesized to be an important factor in fruit retention. The effects of the cultivar and fall ethephon application on ovule longevity were determined.

Ethephon (0 and 500 mg·l-1) was applied to `Italian' and `Brooks' prune trees at the 50% leaf drop stage. The following spring, flower buds were emasculated and covered to prevent pollination. Ten flowers were sampled every two days from anthesis until 20 days after anthesis (DAA). Flowers were fixed in FAP and ovule longevity determined using fluorescence microscopy. Ovule longevity was longer in `Brooks' than `Italian'. At 20 DAA, all of the `Brooks' flowers still had viable ovules. Only 40% of the `Italian' flowers had viable ovules. The `Italian' flowers excised from ethephon-treated trees had at least one non-senescent ovule at 17 DAA. Ethephon prolonged ovule longevity in `Italian' prune flowers. No effect of ethephon was observed on the ovule longevity of the `Brooks' prune.

Free access

Yerko M. Morenol, Anita Nina Miller-Azarenko and William Potts

Flower bud growth and ovule longevity of plum (Prunus domestics L.) cultivars Italian and Brooks and the effects of fall-applied ethephon and of temperature were studied. Fresh and dry weights of terminal flower buds were measured at l-week intervals from 50 days to 1 day before bloom in 1988. Buds were also analyzed for N, P, K, Ca, and B. After bloom, ovule longevity was determined using a fluorescence method after staining with aniline blue. Ovule longevity was determined in 1990 using shoots excised at full bloom from untreated and ethephon-treated trees of both cultivars and held in growth chambers for 18 days at 5, 10, 15, or 20C. `Brooks' flower buds showed a higher accumulation of fresh and dry weight than `Italian', and ethephon reduced bud weights in both cultivars. Ethephon did not affect mineral content of flower buds of `Brooks', but `Italian' flower buds contained a higher concentration of Ca and a lower concentration of P when treated with ethephon. Boron content was higher in the ethephon-treated buds of `Italian' trees on some sampling dates. Ovule longevity was higher for `Brooks' than for `Italian' in both years. Ethephon treatment delayed ovule senescence in `Italian' flowers, but had little or no effect on `Brooks' flowers. Increasing temperatures induced faster ovule senescence in both cultivars. Chemical name used. 2-chloroethylphosphonic acid (ethephon).

Free access

Victor M. Guerrero-Prieto, Mirna Carrasco, Alberto Rodriguez and Don W. Smith

Red Delicious apple is the second most important cultivar grown in the State of Chihuahua, Mexico. Red Delicious apple is well known for pollination problems which can reduce yield. Previous research suggested female sterility might account for irregular fruit set in the apple growing region of Chihuahua. Pollen tube growth and ovule longevity were examined in 1990 under field conditions in Chihuahua. Fluorescent light with Aniline Blue dye was used to determine pollen tube growth and ovule viability. Five days after pollination, 86% of the styles sampled had pollen tubes through the entire style and only 1% of the ovules were non-viable. These results do not support female sterility as the cause of irregular fruit set. Future research might be directed to the question of pollen viability on the stigma.

Restricted access

Qin Yang, Er Liu, Yan Fu, Fuqiang Yuan, Tingting Zhang and Shu Peng

, and ovule longevity under unfavorable temperatures during pollination and fertilization, branches containing inflorescences were placed in a controlled climate chamber at a humidity of 80%. Their stem bases were immersed in 1% (w/v) sucrose, and they

Free access

Patricio A. Brevis, D. Scott NeSmith and Hazel Wetzstein

Effective pollination period (EPP) is the number of days during which pollination is effective to produce a fruit. The EPP is determined by ovule longevity, pollen tube growth rate and length of stigmatic receptivity. The objectives of this research were to establish the EPP of rabbiteye blueberry and to further the understanding of its limiting parameters. The experiments were conducted in growth chambers using blueberry plants of the cultivars Brightwell and Tifblue. Emasculated flowers were hand-pollinated at 0, 2, 4, 6, and 8 days after anthesis (DAA). Ripe fruit were harvested to record percentage fruit set. Stigmatic receptivity was evaluated as the number of germinated tetrads on the stigma 24 hours after pollination. Under day/night temperatures of 23/10 °C, the EPP was 7 days. Stigmatic receptivity was lowest on the day of anthesis and increased as flowers aged. Stigmatic receptivity was not positively correlated to fruit set, therefore, this parameter was not the most limiting factor of the EPP. Observations of pistils pollinated 3 DAA indicated that the fastest growing pollen tubes reached the bottom of the style 2 to 3 days after pollination. Self-pollination resulted in normal pollen tube growth in the style and inside the ovary. Self-pollen tubes were seen penetrating the micropile.

Free access

Patricio A. Brevis, D. Scott NeSmith and Hazel Y. Wetzstein

Rabbiteye blueberry (Vaccinium ashei Reade) often exhibits problems with low fruit set. Little is known about the duration of flower receptivity in this species. The objective of this study was to investigate the effects of flower age at pollination on fruit set, seed number per fruit, and stigmatic receptivity. `Brightwell' and `Tifblue' rabbiteye blueberry plants were kept under controlled conditions in a growth chamber. Day/night temperatures during pollination were 23 °C/10 °C. Flowers were hand pollinated with self- or cross-pollen at 2-day intervals ranging from 0 to 8 days after anthesis (DAA). Flower age at pollination had a significant effect on both fruit set and seed number per fruit. Rabbiteye blueberry flowers were able to produce optimum fruit set during a period of at least five days. Fruit set was markedly reduced 6 to 8 DAA, depending on the cultivar. Flower age at pollination also had a significant effect on stigmatic receptivity, which was assessed as the number of germinated tetrads on the stigma 24 hours after pollination. Stigmas pollinated 0 DAA had a significantly lower number of germinated tetrads than those pollinated 8 DAA. Flower age at pollination and stigmatic receptivity were positively associated. To our knowledge, this is the first quantitative evidence of delayed stigma maturation in blueberry. Stigmatic receptivity and fruit set were not correlated. Overall, the data strongly suggest that stigmatic receptivity was not a limiting factor for fruit set of `Brightwell' and `Tifblue'. It is hypothesized that ovule longevity determines the duration of flower receptivity in these two rabbiteye blueberry cultivars.

Open access

Fuad Gasi, Naris Pojskić, Mirsad Kurtovic, Clive Kaiser, Stein Harald Hjeltnes, Milica Fotiric-Aksic and Mekjell Meland

pollination period (EPP) ( Sanzol and Herrero, 2001 ). EPP is defined as the difference between the ovule longevity minus the time between pollination and fertilization ( Williams, 1965 ). Because of generally unfavorable environmental conditions for pear

Free access

Ricardo Fernández-Escobar, Miguel A. Sánchez-Zamora, Jorge M. García-Novelo and Concepción Molina-Soria

olive fertilization Span. J. Agr. Res. 7 212 223 Fernández-Escobar, R. Ortiz-Urquiza, A. Prado, M. Rapoport, H.F. 2008 Nitrogen status influence on olive tree flower quality and ovule longevity Environ. Expt. Bot. 64 113 119 Fernández-Hernández, A

Free access

María Engracia Guerra, Ana Wünsch, Margarita López-Corrales and Javier Rodrigo

the sweet cherry cultivar 0900 Ziraat Can. J. Plant Sci. 87 593 594 Morenol, Y.M. Miller-Azarenko, A.N. Potts, W. 1992 Genotype, temperature, and fall-applied ethephon affect plum flower bud development and ovule longevity J. Amer. Soc. Hort. Sci. 117