Promotion of Lateral Female Strobili Production in<i>Pinus densiflora</i>by Cytokinin Application at a Specific Stage

Wakushima, Satoru; Yoshioka, Hisashi; Sakurai, Naoki

doi:10.1007/bf02348263

Cited by 10 publications

(9 citation statements)

References 18 publications

(15 reference statements)

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“…In the region where the flowering induction was done, young trees of Pinus patula have a shoot growing period that extends from February up to December at least, with 4-5 successive and overlapping shoot elongation cycles (Gómez-Cárde-nas et al, 1998), so it is difficult to pinpoint the exact timing when the morphological changes associated with bud formation and differentiation are occurring in the terminal leader or first-order lateral branches. On the other hand, the optimum timing for GA 4/7 and stem girdling application might differ with any change in the the importance of optimum application time of treatments to stimulate differentiation of reproductive structures (Greenwood, 1982;Wakushima et al, 1997;Isaza, 2009). In those studies, the optimum period for GA application to promote flowering in Pinus species has ranged from March to September (Luukanen & Johanson, 1980;Greenwood, 1982;Harrison & Slee, 1991;Siregar & Sweet, 1996;Wakushima et al, 1997;Isaza, 2008), depending upon the species and the particular environmental conditions where the studies were done.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, the optimum timing for GA 4/7 and stem girdling application might differ with any change in the the importance of optimum application time of treatments to stimulate differentiation of reproductive structures (Greenwood, 1982;Wakushima et al, 1997;Isaza, 2009). In those studies, the optimum period for GA application to promote flowering in Pinus species has ranged from March to September (Luukanen & Johanson, 1980;Greenwood, 1982;Harrison & Slee, 1991;Siregar & Sweet, 1996;Wakushima et al, 1997;Isaza, 2008), depending upon the species and the particular environmental conditions where the studies were done.…”

Section: Discussionmentioning

confidence: 99%

“…et Cham is one of the most economically important tree species among the subtropical pines natives to Mexico and Central 2 development of female strobili (Owens, 1985), time of application is critical to get both male and female flower induction in these species (Ho & Eng, 1995;Siregar & Sweet, 1996;Wakushima et al, 1997). Thus, GA 4/7 must be applied during the period of shoot elongation, weeks before differentiation of reproductive structures would occur, in order to be effective (Ho & Eng, 1995;Siregar & Sweet, 1996;Muñoz-Gutiérrez et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Effect of giberellic acid (GA4/7) and girdling on induction of reproductive structures in Pinus patula

Vargas-Hernandez¹,

Vargas-Abonce²

2016

For. syst.

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Aim of study: Seed production in forest tree species commonly takes a long time due to the length of the juvenile stage. Even though several treatments have been used to induce early flowering in conifer species, experience on their use in subtropical Pinus species is limited. This study aimed to evaluate the effect of GA 4/7 dose (0, 1.27 and 2.54 mg cm -2 ) and application time (JulyOctober), alone or in combination with partial stem girdling, on male and female strobili production in young Pinus patula Schiede ex Schltdl. et Cham. clones.Area of study: Nine clones with different flowering background of high-elevation Pinus patula growing in a six-year old seed orchard established in Central México (Aquixtla, Puebla) at 2,800 m elevation.Material and methods: Two independent flowering trials (FT 1 and FT 2 ) were carried out in the seed orchard during the 2009 and 2010 flowering cycles; similar factors were evaluated at both trials but time of application, clones tested, and experimental design used varied for each of them. Partial stem girdling was done at the base of the trunk and the GA 4/7 solution was injected into the xylem above the point of girdling. The following spring, the percentage of trees with strobili and the number of strobili per tree were determined for both male and female structures.Main results: Significant differences (p ≤ 0.05) among clones in flowering capacity were found at both trials. None of the treatments applied in FT 1 resulted in an increase of strobili formation, most probably because they were applied too late in the growing season. In FT 2 , however, application of GA 4/7 combined with partial stem girdling increased the percentage of trees with strobili and the number of strobili of both sexes, particularly when applied in early July. Partial stem girdling was more effective on promoting male strobili than female ones in gibberellin-treated grafts.Research highlights: Timing of GA 4/7 application and stem girdling was important, with a significant interaction with clones tested in FT 2 on production of male strobili but not on female strobili. Application of 1.27 mg cm -2 GA 4/7 and stem girdling in July promoted the highest percentage of trees with strobili, and increased 25-fold the number of female strobili and 5-fold the number of male strobili per tree as compared to the control treatment. Thus, operational use of this induction treatment would be valuable to increase and accelerate seed production in Pinus patula seed orchards in the region.Keywords: early flowering; gibberellins; juvenile stage; seed orchard; seed production. Abbreviations: GA: Gibberellic acid; GA 4 : Gibberellic acid 4; GA 7 : Gibberellic acid 7; GA 4/7 : Mix of gibberellic acids 4 and 7;

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of giberellic acid (GA4/7) and girdling on induction of reproductive structures in Pinus patula

Vargas-Hernandez¹,

Vargas-Abonce²

2016

For. syst.

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“…Environmental changes have been shown to induce sexual changes in angiosperms and gymnosperms species with genetically determined dioecious sexual systems in angiosperms (Freeman et al, 1980; Stelkens and Wedekind, 2010). In conifers, changes in sexual expression can be induced experimentally, including the production of bisporangiate strobili, by application of exogenous hormones (Tosh and Powell, 1986; Owens and Hardev, 1990; Wakushima et al, 1997). Changes in hormone levels can be caused by environmental factors such as light intensity (Alabadí and Blázquez, 2009).…”

Section: Discussionmentioning

confidence: 99%

Sexual stability in the nearly dioeciousPinus johannis(Pinaceae)

Flores‐Rentería

Molina‐Freaner

Whipple

et al. 2013

American J of Botany

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• Premise of the study: Even though dioecy is a dominant sexual system among gymnosperms, little is known about its evolutionary history. Pinus johannis may represent a model system because unisexual and monoecious individuals compose its populations. The presence of unisexual individuals in other Pinus species is a consequence of sexual lability. Here we determined whether P. johannis represents the first example of a dioecious or nearly dioecious reproductive system in conifers by evaluating its sexual stability. • Methods: To assess the stability of sexual expression, we quantified the proportion of male vs. female reproductive structures produced by trees over multiple years and tested for the presence of sexual dimorphism. Sexual lability hypotheses were also examined by looking at the relationship between environmental factors and sexual expression and by comparing the reproductive behavior of P. johannis with its closest labile relative, P. edulis. • Key results: Pinus johannis is nearly dioecious: ∼99% of individuals are unisexual or express a low proportion of the opposite gender with few changes in sexual expression through time. We found sexual dimorphism consistent with sexual stability. Sexual expression did not vary with tree size/age, abiotic environment, or herbivore removal, providing evidence against sexual lability. Individuals of P. johannis tended to produce only male or female strobili, whereas those of P. edulis were mainly monoecious with a gradient in the female to male strobili ratio. • Conclusions: This study represents the first report of a nearly stable dioecious Pinus species. The variety of sexual morphs coexisting in the same population makes P. johannis a model for studying the evolution of dioecy in gymnosperms.

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“…Benzlaminopurine (BA) is a synthetic cytokinin with a structure resembling adenine (Kong et al 2004). Benzlaminopurine treatments were shown to increase flower and cone production in Japanese red pine and Japanese black pine (Pinus thunbergii) (Wakushima et al 1996(Wakushima et al , 1997Wakushima 2004).…”

Section: Introductionmentioning

confidence: 99%

Effects of gibberellin A4/7, 6-benzylaminopurine and chlormequat chloride on the number of male and female strobili and immature cones in Chinese pine (Pinus tabuliformis) with foliar sprays

Zhao

Fan

Zhang

et al. 2011

Journal of Forestry Research

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Promotion of Lateral Female Strobili Production inPinus densifloraby Cytokinin Application at a Specific Stage

Cited by 10 publications

References 18 publications

Effect of giberellic acid (GA4/7) and girdling on induction of reproductive structures in Pinus patula

Effect of giberellic acid (GA4/7) and girdling on induction of reproductive structures in Pinus patula

Sexual stability in the nearly dioeciousPinus johannis(Pinaceae)

Effects of gibberellin A4/7, 6-benzylaminopurine and chlormequat chloride on the number of male and female strobili and immature cones in Chinese pine (Pinus tabuliformis) with foliar sprays

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