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- Author or Editor: P. Gavinlertvatana x
Fifty-four out of 67 species of bamboo tested were successfully propagated in vitro. For nearly every species, multiple shoots were produced from axillary buds on stem node segments cultured on Murashige and Skoog medium containing BA. In a very few species plants could be regenerated adventitiously from callus. This method of propagation was not very efficient or reliable. Rooting occurred in media containing NAA at 2.7 to 5.4 μM. Several species could be stored in vitro on half-strength medium at room temperature > 15 months without transfer. Chemical names used: N6-benzylamino purine (BA); napthyleneacetic acid (NAA).
Pretreatment of excised leaves of Petunia hybrida L. with AgNO3 permitted shoot formation equal to the control, when explants were cultured on a medium containing 6-benzylamino purine (BA), but increased callus formation, chlorophyll content, and ethylene production. When explants were cultured on a medium containing α-naphthaleneacetic acid (NAA), pretreatment with AgNO3 promoted callus growth, root formation and extension, and ethylene production, but inhibited root hair formation. Pretreatment of explants with CuSO4 suppressed ethylene production and chlorophyll content. Inclusion of AgNO3 partially overcame the effects of CuSO4 alone. When the rhizobitoxine analog, L-2-amino-4-(2-aminoethoxy)-trans-3-butenoic acid (Rh), was used for pretreatment, ethylene emanation was inhibited for 2 or 3 weeks. Number of shoots and roots, root length, root hair and callus formation were not affected by Rh except that callus growth was reduced on a medium containing NAA. NAA (1.0 mg/liter) promoted callus and root formation and induced high levels of ethylene, while kinetin (0.2 mg/liter) stimulated shoot formation but simultaneously induced much lower levels of ethylene.
Biologically active levels of ethylene were accumulated in flask atmospheres of leaf segments and callus of dahlia cultured in vitro. The ethylene levels were dependent on concentrations of α-naphthaleneacetic acid (NAA) and 6-fur-furylamino purine (kinetin) in the medium. NAA promoted ethylene levels to a greater degree than kinetin. NAA at 1 mg liter, but not 5 or 10 mg liter, interacted with kinetin to stimulate ethylene synthesis. Reducing ethylene concentrations in the flasks by potassium permanganate absorption had no effect on callus formation from leaf tissue.
Ethylene (C2H4) and CO2 levels and callus formation were influenced by photoperiods (8 hours-SD; 16 hours-LD) under which ‘Nita’ dahlia stock plants were grown and leaf segments incubated in vitro. Larger callus and higher levels of C2H4 and CO2 were detected when tissues from stock plants under SD were incubated under SD (SD-SD) than when incubated under LD (SD-LD). Tissue under LD-LD or LD-SD formed similar amounts of callus to SD-LD cultures, but C2H4 and CO2 levels were higher. Compared to water-sprayed controls, 2500 mg/liter butanedioic acid mono-(2,2-dimethylhydrazide) (daminozide) sprayed on SD stock plants one day before explant removal promoted callus formation, and C2H4 and CO2 production in tissue incubated under either SD or LD. Daminozide sprayed on LD stock plants had no influence on callus or C2H4, but CO2 was increased under SD or LD incubation.