عنوان مقاله
کانکین کوتاه 1، یک جهش یافته جدید ازcastanea mollissima با مرگ برنامه ریزی شده سلول مرتبط با پرچم گل در طول تمایز
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چکیده
مقدمه
مواد و روش ها
نتایج
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بخشی از مقاله
پیشرفت نمو و مشخصه های گل های نر با SCK1
شکوفه ها محتوی گل آذین اولیه SCK1 جوانه زنی را آغاز می کنند و همزمان رویش شاخه به عنوان شکوفه های نوع وحشی (شکل 1A-E). اگرچه وقتی کاتکین ها حدود 2 سانتی متر در طول رشد می کنند (شک ل1F)، قطعه دور گل آذین نر روی SCK1 شروع به توقف رشد می کنند به زردی می گرایند و به تدریج حلقه ای می شوند (شکل L,1G) و سرانجام پس از 15 روز یا بیشتر پژمرده می شود.
کلمات کلیدی:
Short catkin1, a novel mutant of Castanea mollissima, is associated with programmed cell death during chestnut staminate flower differentiation Yong-qing Fenga,b, Yuan-yue Shenb, Ling Qinb,∗, Qing-qin Caoc, Zhen-hai Hana a College of Agriculture and Biotechnology, China Agricultural University, Beijing 100193, China b Key Laboratory of New Technology in Agriculture Application of Beijing, College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China c College of Biotechnology, Beijing University of Agriculture, Beijing 102206, China article info Article history: Received 31 January 2011 Received in revised form 5 July 2011 Accepted 9 July 2011 Keywords: Chinese chestnut Short catkins Floral mutation Programmed cell death abstract The fact that male flowers far outnumber female flowers is a factor that limits nut yield in Chinese chestnut. A naturally occurring mutation of male catkins was found on a single branch of a Chinese chestnut tree in the mountains near Beijing, China. The mutation was named short catkin1 (sck1). The catkin length of sck1 was only 1/6 to 1/8 that of the wild-type male catkins on the same tree. The mutation was associated with a greater number of female flowers and increased yield. Observations on the development of male catkins with the sck1 phenotype showed that the distal part of the catkins aborted at the stage of chestnut staminate flower differentiation. Further research using transmission electron microscope analysis showed that the process of cell death in sck1 catkins had the typical characteristics of programmed cell death at the subcellular level, such as condensed chromatin, dissolved nucleolus, degraded karyoplasm, burst karyotheca, and disintegrated chloroplasts or mitochondria. Significantly, DNA laddering was detected in tissues of sck1 catkins. In conclusion, the results showed that sck1 was associated with PCD. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Chinese chestnut (Castanea mollissima Bl.) is an important tree species both for its ecological and economic value. However, the fact that male flowers far outnumber female flowers results in relatively low nut yield. Accordingly, improving nut yields has been a focus of research (Shi and Stösser, 2005; Zhang and Su, 2007). As a monoecious plant, chestnut produces two types of catkins, unisexual catkins with only male flowers and bisexual catkins with functional male and female flowers. When female flowers begin to differentiate in the spring, they undergo a stage of nutrition competition because of rapid vegetative and reproductive growth. Nearly 40% of the intrinsic nutrition from a chestnut tree is consumed by development of the male inflorescences (Feng et al., 1995). Therefore the abundant male flower development can largely limit the female-flower differentiation. The proportion of male to female flowers in each shoot is about 1000–3000:1 (Shi and Stösser, 2005). As a result, thinning 90–95% of the male inflorescences by hand or by a chemical agent could significantly increase nut yield (Liu et al., 1999; Zhao and Liu, 1999). But thinning male inflorescences is time-consuming and labor intensive. ∗ Corresponding author. Tel.: +86 10 80797229; fax: +86 10 80796917. E-mail addresses: qinling@bac.edu.cn, qinlingbac@126.com (L. Qin). Recently, a natural mutant of chestnut with extremely short catkins was found on a single branch of a chestnut tree in a mountainous area near Beijing, China. The mutation was named short catkin1 (sck1). In the present study, we provided that both morphological and molecular evidence to demonstrate sck1 was associated with programmed cell death (PCD). Sck1 markedly decreases the number of flowers in the male catkins, and at the same time promotes more female-flower differentiation, thereby increasing nut yield. 2. Materials and methods 2.1. Plant material Phenotypic characters were investigated and buds were sampled on current-year shoot once a week from mid-June of one year to mid-May of the next year except for the dormant period in the fall and winter. The experiment used ten 3-year-old grafted trees with the mutant catkin phenotype. 2.2. Interior morphological analysis 2.2.1. Paraffin-sectioning The sample buds and catkins were fixed in formalin–acetic acid–alcohol (FAA) for 24–48 h at room temperature and then stored at 4 ◦C. Paraffin embedding was done as follows: 70% 0304-4238/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.scienta.2011.07.014
