high-quality and pathogen-free planting materials and reducing production costs. Hyperhydricity has been described as a physiological disorder of tissue-cultured plants whereby the hyperhydric propagules become translucent due to excessive hydration of
M.E. El-Mahrouk, A.R. El-Shereif, Y.H. Dewir, Y.M. Hafez, Kh. A. Abdelaal, S. El-Hendawy, H. Migdadi and R.S. Al-Obeed
Ayse Tascan, Jeff Adelberg, Mevlut Tascan, Agnes Rimando, Nirmal Joshee and Anand K. Yadav
Scutellaria germplasm, including rare species, and to characterize secondary metabolism ( Cole et al., 2007 ). Hyperhydricity is a physiological disorder frequently affecting shoots vegetatively propagated in vitro ( Tascan et al., 2007 ). Hyperhydric shoots
Wei-Ting Tsai and Chien-Young Chu
, hyperhydricity (or vitrification) was a serious problem in long-term liquid culture ( Etienne and Berthouly, 2002 ; Ziv, 1994 ). The hyperhydric materials were unable to grow into normal plants, and it was hard to recover to a normal state ( Zhou, 1995 ). In
Hua Q. Zhao, Qing H. He, Li L. Song, Mei F. Hou and Zhi G. Zhang
cultured × 100), shoot regeneration frequency (explants with shoots/number of explants cultured × 100), and hyperhydricity frequency (explants with hyperhydric shoots/number of explants cultured × 100) were recorded after 6 weeks of culture. Rooting and
Georgia Vlachou, Maria Papafotiou and Konstantinos F. Bertsouklis
of storage and temperature on C. nepeta seed germination ability, and 2) the effect of various plant growth regulators and agar concentrations on in vitro shoot proliferation, elimination of hyperhydricity problems, and microshoot rooting. Materials
Masanori Kadota and Yoshiji Niimi
We investigated the influence of sorbitol, sucrose, fructose, glucose, maltose, lactose, and mannitol carbon sources at various concentrations on shoot proliferation, hyperhydricity and rooting of pear. Shoot tips were cultured in woody plant medium (Lloyd and McCown, 1981) containing 11.0 μm 6-benzyladenine, 0.5 μm indole-3-butyric acid, 0.8% (w/v) agar and 30, 60, or 120 mm of each of seven carbon sources for eight weeks. Sorbitol at 60 mm was the most effective carbon source for shoot proliferation. Using 30 mm sorbital and 30 and 120 mm sucrose resulted in a high number of hyperhydric explants. Shoots rooted with 60 mm glucose, sucrose and sorbitol in media; media with sucrose resulting in the highest rooting frequency, root number and root length. Shoots failed to root when fructose, lactose, maltose, or mannitol were used.
Guochen K. Png, Katherine S. Downes and Beng H. Tan
, 1993 ); and the elevation of hyperhydricity in a concentration-dependent manner ( Debergh et al., 1992 ; Ivanova et al., 2006 ; Kevers et al., 2004 ). Hyperhydricity (previously known as vitrification) refers to the malformed and watery appearance of
Takuya Tetsumura and Kensuke Yamashita
Japanese chestnut (Castanea crenata Sieb. et Zucc.) was micropropagated from nodal explants of 2-month-old seedlings, and the regenerated plantlets were acclimatized after potting. For in vitro establishment, 5 μm zeatin was more effective than 5 μm BA or TDZ, and Sato's (BW) medium was as effective as MS(½NO3) medium. Driver-Kuniyuki walnut medium produced more shoots showing hyperhydricity symptoms. In the multiplication culture, the higher the concentration of zeatin added to BW medium, the greater the number of shoots showing hyperhydricity, although the longest shoot was obtained when 6.9 μm zeatin was added. After planting in ½BW medium with 15 μm IBA for 5 d to induce rooting, shoots planted in ½BW medium plus vermiculite gelled with Gellan Gum (SV substrate) rooted better than those in either the gelled medium without vermiculite (S substrate) or vermiculite plus liquid medium (V substrate). One third of the shoots planted in the V substrate died, although 62% of the surviving shoots rooted well. Of the shoots planted in the S substrate, 83% survived, but only 35% of these survived rooting. Shoots rooted in the SV and V substrates survived well after the completion of acclimatization, and shoots rooted in the SV substrate grew more vigorously after potting. Chemical names used: 6-benzyladenine (BA); 6-(4-hydroxy-3-methyl-but-2-enylamino)purine (zeatin); indole-3-butyric acid (IBA); 1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea (thidiazuron, TDZ).
Linda J. Walker, R.B. Rogers and M.A.L. Smith
In vitro cell cultures of huckleberry and bilberry are sources of phytochemicals for use as food colorants and bioactive chemopreventives. Shoot cultures provide a convenient, presterile source of explants for production of callus rich in extractable pigments or other chemicals. Efficient callus formation only occurs with good-quality shoots. In this study, liquid and gelled support systems were compared in terms of their effect on shoot growth. Gellan gum-based support resulted in excellent shoot proliferation and suitable shoot length for huckleberry cultures, whereas bilberry performed slightly better on agar and agar/gellan gum support. Bilberry had a more-rapid growth rate than huckleberry. Hyperhydricity was found with the use of rafts for both species. These shoot cultures have been used as vegetative explants for callus, and have produced vivid anthocyanins in solution cultures.
Margarita Fraga, Mertxe Alonso, Philippe Ellul and Marisé Borja
Meristem culture and/or thermotherapy were used to eliminate viruses from ornamental Dianthus gratianopolitanus Vill. (`Spotti' and `Frosty Fire') mother plants. Shoot tip, leaf, node, and ovary explants collected from greenhouse-maintained, virus-free plants were cultured in vitro for shoot initiation on Murashige and Skoog (MS) medium containing BAP, kinetin, or 2-iP with or without IAA or NAA. Culture of shoot tips in MS with 0.57 μm IAA and node explants in MS with 2.46 μm 2-iP is recommended for `Spotti' cultivar. In `Frosty Fire', optimum number of axillary shoots was obtained from shoot tip and node explants in MS without plant regulators. Leaves and ovaries were not adequate explants for D. gratianopolitanus micropropagation because none or only a low percentage of explants regenerated shoots. High levels of cytokinins increased the number of shoots per explant but also increased the production of aberrant phenotypes and induced hyperhydricity. Adventitious shoots rooted in vitro with auxins, but maximum rooting was 97% ex vitro without auxins. This study demonstrated that D. gratianopolitanus can be successfully micropropagated. Chemical names used: 6-benzyladenine (BAP); kinetin (KIN); 6-(γ,γ-dimethylallylamino)-purine (2iP); indole-acetic acid (IAA); indole-3-butyric acid (IBA); α-naphthaleneacetic acid (NAA); gibberellic acid (GA3).