scholarly journals Influence of Root Zone Calcium on Subapical Necrosis in Potato Shoot Cultures: Localization of Injury at the Tissue and Cellular Levels

2008 ◽  
Vol 133 (5) ◽  
pp. 653-662 ◽  
Author(s):  
James S. Busse ◽  
Senay Ozgen ◽  
Jiwan P. Palta
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Dominance ◽  
Apical Meristem ◽  
Calcium Deficiency ◽  
Shoot Tip ◽  
Axillary Shoot ◽  
Shoot Cultures ◽  
Primary Injury ◽  
Shoot Tip Necrosis

Shoot tip necrosis has been attributed to calcium deficiency in in vitro cultures, resulting in death of the stem tip, the loss of apical dominance, and axillary branch development. Using an in vitro shoot culture system with Solanum tuberosum L. cv. Dark Red Norland, we studied the development of injury symptoms at the microscopic and tissue levels at a range of media calcium concentrations varying from 6.8 to 3000 μm. Light and electron microscopic studies revealed that the primary injury due to calcium deficiency was the death and collapse of expanding pith cells below the shoot apex. The structure and organization of the shoot apical meristem was the same when plants were cultured on sufficient or suboptimal media calcium concentrations. However, the apical meristem senesced following subapical shoot tissue collapse. Death of the shoot apical meristem was a secondary effect of calcium deficiency, resulting in loss of apical dominance. Studies with 45Ca indicated that calcium was distributed in a gradient along the shoot, with highest concentration at the base and the lowest at the apex. Shoot tip necrosis developed after 20 days of culture on the suboptimal calcium concentration medium. The development of these symptoms and axillary shoot growth was associated with the lack of calcium accumulation in the shoots. Our results provide evidence that a primary injury of calcium deficiency is localized in the expanding pith cells below the shoot apical meristem and this injury results in the collapse of subapical cells. Death of the shoot apical meristem is a secondary injury resulting from calcium deficiency.

scholarly journals Vegetative Propagation of Phytophthora cinnamomi-Tolerant Holm Oak Genotypes by Axillary Budding and Somatic Embryogenesis

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 841
Author(s):  
Maria Teresa Martínez ◽  
Francisco Javier Vieitez ◽  
Alejandro Solla ◽  
Raúl Tapias ◽  
Noelia Ramírez-Martín ◽  
...  
Keyword(s):  
Somatic Embryogenesis ◽  
Somatic Embryos ◽  
Phytophthora Cinnamomi ◽  
Shoot Proliferation ◽  
Holm Oak ◽  
Induction Medium ◽  
Axillary Shoot ◽  
Oak Decline ◽  
Shoot Cultures

Holm oak (Quercus ilex) is one of the most widely distributed tree species in the Mediterranean basin. High mortality rates have been observed in holm oak populations in the southwest of the Iberian Peninsula as a result of oak decline syndrome. Selection and propagation of genotypes tolerant to this syndrome could aid the restoration of affected areas. In this article, we report micropropagation and conservation procedures based on axillary budding and somatic embryogenesis (SE) of holm oak plants, selected for their tolerance to Phytophthora cinnamomi—the main biotic factor responsible for oak decline. Forced shoots were obtained from potted plants of eight different genotypes, and used as stock material to establish in vitro shoot proliferation cultures. Reliable shoot proliferation was obtained in seven out the eight genotypes established in vitro, whereas multiplication rates were genotype-dependent. The highest rooting rates were obtained by culturing shoots for 24 h or 48 h on rooting induction medium containing 25 mg L−1 indole-3-butyric acid, followed by transfer to medium supplemented with 20 µM silver thiosulphate. Axillary shoot cultures can be successful conserved by cold storage for 12 months at 4 °C under dim lighting. Shoot tips, excised from axillary shoot cultures established from tolerant plants, were used as initial explants to induce SE. Somatic embryos and/or nodular embryogenic structures were obtained on induction medium with or without indole-acetic acid 4 mg L−1, in two out the three genotypes evaluated, and induction rates ranged between 2 and 4%. Plantlet recovery was 45% after two months cold stratification of somatic embryos and eight weeks of culture on germination medium. Vegetative propagation of P. cinnamomi-tolerant Q. ilex trees is a valuable milestone towards the restoration of disease-affected areas.

scholarly journals Influence of Ca2+ and 6-benzyladenine on chestnut (Castanea sativa Mill.) in vitro shoot-tip necrosis

Plant Science ◽  
1996 ◽  
Vol 118 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Claudia Piagnani ◽  
Graziano Zocchi ◽  
Ilaria Mignani
Keyword(s):  
Castanea Sativa ◽  
Shoot Tip ◽  
Castanea Sativa Mill ◽  
Shoot Tip Necrosis

TWO TYPES OF ALBUGO-INDUCED GALLS ON IPOMOEA PENTAPHYLLA AND THEIR MORPHOGENETIC INTERPRETATION

1966 ◽  
Vol 44 (5) ◽  
pp. 535-540
Author(s):  
Hardev Singh ◽  
Krishna Bedi
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Rate Of Development ◽  
Distinct Morphology

Ipomoea pentaphylla Jacq. is a twining, hirsute annual. After infection by Albugo ipomoeae-panduranae (Schw.) Swingle, two types of galls develop on the stem—bud and cerebriform. The bud gall originates from an infected bud while the cerebriform gall arises from the internode. The two types are distinct from each other in their morphology, anatomy, rate of development, and morphogenesis. The bud gall is of the organoid type while the cerebriform gall is of the histioid type. Tissues of the bud gall grown under in vitro conditions give rise to a structure like the cerebriform gall. The very distinct morphology of the two types has been interpreted on the basis of the possible organizing influence of the shoot apical meristem.

scholarly journals Pengaruh TDZ terhadap induksi embrio somatik sagu (Metroxylon sagu Rottb.) pada tiga metode kultur berbeda (Effect of TDZ on the somatic embryo induction of sago palm (Metroxylon sagu Rottb.) in three different culture methods)

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Imron Riyadi ◽  
Darda EFENDI ◽  
Bambang S PURWOKO ◽  
Djoko SANTOSO
Keyword(s):  
Somatic Embryo ◽  
Shoot Apical Meristem ◽  
Embryogenic Callus ◽  
Somatic Embryos ◽  
Apical Meristem ◽  
Culture Methods ◽  
Sago Palm ◽  
Callus Differentiation ◽  
Metroxylon Sagu

AbstractA right combination of cytokinin is able to support the process of callus differentiation to somatic embryo formation in plant somatic embryogenesis. Liquid culture application could increase the efficiency of in vitro culture process on plants. This research aimed to determine the best concentration of TDZ combined with kinetin for callus differentiation to  somatic embryo of sago palm on three culture methods. Plant material used was embryogenic callus derived from tips meristem culture from sucker of Alitir sago palm. Callus was cultured on modified MS media added with: 0.0, 0.1, 0.5 and 1.0 mg/L TDZ combined with 0.5 mg/L kinetin for 12 weeks with subcultures every 6 weeks. Three culture methods used were suspension, temporary immersion system (TIS), and solid media. There were 12 treatments with 4 replicates. The results showed that the highest number of somatic embryos was achieved on TIS culture with 1.0 mg/L TDZ and 0.5 mg/L kinetin in 6 weeks (167.3 embryos/flask) and 12 weeks (389.2 embryos/flask) with its fresh weight of 18.4 g and 29.1 g, respectively. The highset survival rate in final culture (12 weeks) was achieved on TIS culture with 1.0 mg/L TDZ and 0.5 mg/L kinetin (100%). The shortest time for somatic embryos expression was achieved on TIS culture with 1.0 mg/L TDZ and 0.5 mg/L kinetin in two weeks after culture. Histological analysis of early-stage somatic embryos showed the presence of dense and compact cellular arrangements which formed growth spot axis for shoot or SAM (shoot apical meristem) and root or RAM (root apical meristem) that connected each other. [Key words: culture method, embryogenic callus, Metroxylon sagu Rottb., kinetin, sago palm, TDZ]   AbstrakAplikasi kombinasi sitokinin yang tepat dapat mendorong proses diferensiasi kalus membentuk embrio somatik pada proses embriogenesis somatik tanaman. Penggunaan metode kultur cair dapat meningkatkan efisiensi proses kultur in vitro tanaman. Penelitian ini bertujuan untuk menentukan konsentrasi TDZ terbaik dikombinasikan dengan kinetin dalam proses diferensiasi kalus membentuk embrio somatik tanaman sagu pada tiga metode kultur. Bahan tanam penelitian  berupa kalus embriogenik tanaman sagu asal kultur meristem pucuk dari anakan sagu jenis Alitir. Kalus dikulturkan pada media modifikasi dengan penambahan  TDZ dengan konsentrasi 0,1; 0,5; dan 1,0 mg/L dikombinasikan dengan kinetin 0,5 mg/L selama 12 minggu yang disubkultur pada umur 6 minggu. Metode kultur yang digunakan terdiri atas tiga macam yaitu: kultur suspensi, sistem perendaman sesaat (SPS) dan media padat. Perlakuan terdiri atas 12 kombinasi perlakuan dengan empat ulangan. Hasil penelitian menunjukkan bahwa rerata jumlah embrio somatik tertinggi dicapai pada perlakuan metode kultur SPS dengan TDZ 1,0 mg/L baik pada umur kultur 6 minggu (167,3 buah) maupun umur 12 minggu (389,2 buah). Rerata bobot segar tertinggi juga diperoleh pada perlakuan metode kultur SPS dengan TDZ 1,0 mg/L  pada umur kultur 6 minggu (18,4 g) dan  12 minggu (29,1 g). Rerata daya hidup kultur akhir (12 minggu) tertinggi  sebesar 100% diperoleh pada perlakuan SPS. Induksi embrio somatik  tercepat yakni setelah  dua minggu diperoleh pada  metode kultur SPS dengan TDZ 1,0 mg/L dikombinasikan dengan kinetin 0,5 mg/L. Analisis histologi embrio somatik stadium awal  menunjukkan adanya susunan sel yang rapat dan kompak yang menyusun semacam poros atau berkas titik tumbuh tunas atau SAM (shoot apical meristem) maupun akar atau RAM (root apical mersitem) yang saling terhubung.[Kata kunci: kalus embriogenik, metode kultur, kinetin, TDZ, sagu, Metroxylon sagu]

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