and reliable protocol for the micropropagation of wolfberry ( Lycium barbarum L.), focusing on the effects of mineral salts, growth regulators, and in vitro and ex vitro rooting. The simplicity of the present protocol aims not only to promote the
Cristian Silvestri, Gianmarco Sabbatini, Federico Marangelli, Eddo Rugini, and Valerio Cristofori
Doina Clapa, Alexandru Fira, and Nirmal Joshee
paclobutrazol or Cycocel, and the use of antitranspirants. Examples of successful direct ex vitro-rooted plants are citrus, tea, walnut, peach, tobacco, and brinjal. The author further suggests application of direct ex vitro rooting of shoots deriving from the
W.L. Chen and D.M. Yeh
the shoot multiplication, and to evaluate the effects of auxins on ex vitro rooting of microcuttings in Aglaonema . Materials and Methods Plant material and culture conditions. Stock plants of Aglaonema ‘White Tip’ were grown in a 70
Dorcas K. Isutsa, Marvin P. Pritts, and Kenneth W. Mudge
A protocol is presented that enables a propagator to produce field-sized blueberry transplants within 6 months of obtaining microshoots from tissue culture. The protocol involves subjecting microshoots to ex vitro rooting in a fog chamber under 100 μmol·m–2·s–1 photosynthetic photon flux for 7 weeks, transferring plants to a fog tunnel for 2 weeks, then to a greenhouse for 7 more weeks. Plant survival and rooting of cultivars Berkeley (Vaccinium corymbosum L.) and Northsky (Vaccinium angustifolium ×corymbosum) were near 100% under these conditions. Plantlets in fog chambers receiving 100 μmol·m–2·s–1 grew rapidly, while those at lower irradiance levels grew more slowly, and supplemental CO2 enhanced growth only at 50 μmol·m–2·s–1. Growth rates slowed when plants were moved into the fog tunnel; but by the end of 16 weeks, plants that were under high irradiance in the fog chamber had root systems that were 15 to 30 times larger than plants under low irradiance. Within 6 months, these plants were 30 to 60 cm tall and suitable for field planting.
Charlotte R. Chan and Robert D. Marquard
Hamamelis cultivars are typically propagated by grafting onto H. virginiana rootstock. Grafting is labor-intensive and the understock frequently suckers which can lead to the loss of the scion. A cultivar growing on its own root system would eliminate this problem. Our research was undertaken to develop a successful method of rooting micropropagules. The source material was established cultures of H. × intermedia `Diane,' H. virginiana, and a H. vernalis selection. The rooting treatments consisted of four concentrations of K-IBA (0, 5, 10, and 20 μM) in 0.02% Tween 80. Three replicates of eight cuttings each were taken from the three sources for each of the four treatments. The cuttings were placed in 50-mL beakers, cut-end down, with 10 mL of the treatment solution. The beakers were sealed with Parafilm, and cuttings were soaked for 24 h. After treatment, the cuttings were randomly stuck into Kadon flats prepared in advance with a sterile mix of 1 peat: 1 perlite and were watered-in. Cuttings were misted, and flats were covered with plastic and Remay. They were kept in a warm (19-24 °C) greenhouse. Cuttings rooted in 3 to 4 weeks and were subsequently fertilized weekly with Peter's 20N-20P-20K at 150 ppm. At 12 weeks, data were collected for the rate of survival, height, branching, number of nodes, and root mass, and the plants were transplanted to quart pots. Ninety percent of the cuttings rooted; the most favorable response was with 10 μM K-IBA, although all treatments produced >80% rooting. This method was time and labor efficient. Moreover, micropropagation is not dependent on the season, and production of new plants could proceed on a continuous basis, making this a viable alternative to commercial grafting.
Marvin Pritts and Dorcas Isuta
Previous findings reveal that rooting and acclimatization of apple and blueberry plants is often difficult, inconsistent and inefficient. This experiment was set up in a fog chamber lo investigate the effects of CO2 enrichment (CDE) and irradiance on unrooted stage II microshoots. Two CO2 and 3 light levels tested were: 1350 +/- 150 (+ CDE), and 450 +/- 50 (- CDE) ppm; 30 +/- 5 (low), 55 + 10 (medium), and 100 + 20 (high) umolm-2s-1 respectively. Cultivars assessed were Berkeley and Northsky for blueberry. G65 and NY30 for apple. Blueberry microshoots acclimatized successfully and gave between 90 to 100% rooting and survival rate. Apple microshoots acclimatized and rooted slowly, exhibited great sensitivity to in vivo conditions and gave between 40 to 100% rooting and survival rate. High light induced photo-inhibition which disappeared after complete acclimatization. There was a significant difference between low light and the other two light levels. The effect of CDE was dependent on cultivar. In most cases, high light (-) CDE gave the most vigorous growth (highest plant dry weight and leaf area). There was a significant difference between (+) CDE and (-) CDE at low and medium light, but none at high light. Low light (-) CDE and medium light (+) CDE were superior over low light (+) CDE and medium light (-) CDE. respectively. Stalling out in apple microshoots was corrected by GA sprays.
Xiaoling Yu and Barbara M. Reed
A micropropagation system was developed for hazelnut cultivars. Grafted greenhouse-grown plants produced many more viable explants than upper branches of mature field-grown trees. Shoots from grafted greenhouse-grown plants collected March through July and suckers of mature field-grown trees collected in July produced the most growing explants (46% to 80%). Three- to five-fold multiplication was obtained after 4 weeks of culture on NCGR-COR medium supplemented with 6.7 μm BA and 0.04 μm IBA. Roots were produced on 64% to 100% of shoots grown on half-strength NCGR-COR mineral salts and 4.9 μm IBA for 4 weeks. Ex vitro rooting by a brief dip in 1 or 5 mm IBA was equally successful. Transplant survival was 78% to 100%. Chemical names used: N 6-benzyladenine (BA); indole-3-butyric acid (IBA).
Samir C. Debnath
In an attempt to improve the micropropagation protocol for lingonberry (Vaccinium vitis-idaea L.) developed at the Centre, two lingonberry clones were compared for in vitro shoot proliferation on two different media supplemented with varying levels of thidiazuron (TDZ). TDZ supported proliferation at low concentrations (0.1 to 1 μm) but inhibited shoot elongation. However, usable shoots were obtained within 4 weeks by transferring shoot cluster to medium containing 1 μm zeatin. Genotypes differed significantly with respect to multiplication rate with `EL1' producing the most shoots per explant. In both genotypes, shoot proliferation was greatly influenced by explant orientation. Changing the orientation of explants from vertically upright to horizontal increased axillary shoot number, but decreased shoot height and leaf number per shoot. Proliferated shoots were rooted on a 2 peat: 1 perlite (v/v) medium, and the plantlets were acclimatized and eventually established in the greenhouse.
Samir C. Debnath
In an attempt to improve the micropropagation protocol for lowbush blueberry (Vaccinium angustifolium Ait.), a protocol using a bioreactor system combined with a semisolid gelled medium has been developed. Cultures of cultivar Fundy and two wild clones (‘NB1’ and ‘QB1’) were established in vitro on a gelled modified cranberry basal medium (BM) containing 5 μM zeatin or 10 μM N6-[2-isopentenyl]adenine. Multiple shoots were obtained within 8 weeks by transferring zeatin-induced shoots from the gelled BM to a bioreactor containing liquid BM with 1 to 4 μM zeatin. Genotypes differed significantly with respect to multiplication rate in liquid and gelled BM containing 1 μM zeatin with ‘NB1’ producing 8.5 ± 1.1 and 2.9 ± 0.3 shoots per explant in liquid and gelled media, respectively, after one subculture followed by ‘QB1’ (7.1 ± 0.6 and 2.6 ± 0.4 shoots per explant, respectively) and ‘Fundy’ (5.8 ± 0.4 and 2.0 ± 0.2 shoots per explant, respectively). With subculture, there was an increase of shoot multiplication rate for all genotypes. Bioreactor- and gelled medium-proliferated shoots were treated with 39.4 mm indole-3-butyric acid powder, rooted in a 2 peat:1 perlite (v/v) medium, plantlets acclimatized, and eventually established in the greenhouse with 64% to 74% rooting of microshoots and 90% to 99% survival of rooted shoots. Results obtained suggested the possibility of large-scale multiplication of lowbush blueberry shoots in bioreactors.
Boling Liu, Hongzhou Fang, Chaorong Meng, Ming Chen, Qingdong Chai, Kai Zhang, and Shijuan Liu
Soil, Deli, Fuzhou, China; 1:1, v/v), and established in the greenhouse for simultaneous ex vitro rooting. The rooting percentage was calculated as follows: Table 4. Effect of 1-naphthaleneacetic acid on root induction in micropropagated plantlets of H