The regeneration potential of shoot apical meristems of soybean, cowpea, peanut, chickpea, and bean was studied on agar-solidified MS nutrient medium supplemented with various concentrations of benzyladenine (BA) and napthaleneacetic acid (NAA) alone or in combination. Soybean plantlets could be regenerated only when 0.05–0.1 μM BA was applied in conjunction with 1 μM NAA. Cowpea meristems did not require exogenously supplied hormones for maximum (100%) plant regeneration to occur. Extremely low levels of BA (0.1–0.005 μM) in association with low levels of NAA (0.05 μM) also induced plant regeneration at very high frequency. Similarly, bean meristems differentiated into plantlets on hormone-free medium or on medium containing only the auxin, NAA. Multiple bud regeneration (15–30 buds per meristem) was induced from bean meristems at high cytokinin levels (10 μM BA). Elongated bean shoots differentiated roots on half-strength MS medium containing 1 μM indoleacetic acid (IAA). Although most combinations of BA or BA and NAA induced shoot regeneration from peanut and chickpea meristems, whole plant regeneration occurred more frequently (75%) from the former only when 0.1 μM BA was applied in combination with 10 μM NAA. Multiple axillary branching occurred from the main shoots regenerated from chickpea meristems; however, rooting occurred only when these shoots were recultured on medium containing 1 μM indolebutyric acid (IBA). Plantlets regenerated from the meristems of all these grain legumes were successfully transferred to pots and grown to maturity.

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Meristems isolated from strawberry (Fragaria X ananassa Duch. cv. Redcoat) runner-tips were cultured on a Murashige and Skoog (MS) medium supplemented with 6-benzylamino purine (BA), indolebutyric acid (IBA) and gibberellic acid (GA3) at concentrations of 1, 1 and 0.1 μm, respectively. The meristems regenerated shoots within 3 to 4 weeks when incubated at 26°, 16 hour photoperiods and 4000 lux intensity. On medium supplemented with BA at a concentration of 10 μm these shoots proliferated into “clumps,” each consisting of 150 to 200 shoots. Meristems isolated from these in vitro shoots were precultured on medium supplemented with dimethylsulfoxide (DMSO) or glycerol as cryoprotectants, frozen either slowly at cooling velocities of 0.5° to 1.0°C/minute to −40° or rapidly and stored in liquid nitrogen (−196°). Maximum viability and plant regeneration (95%) was obtained when the meristems were precultured on medium supplemented with 5% DMSO, and then frozen at a cooling velocity of 0.84°/min. A viability of 35% was observed when meristems precultured on 5% glycerol-supplemented medium for 3 days were frozen at a cooling velocity of 0.94°/min. Rapid freezing and rapid dry freezing using either DMSO or glycerol resulted in reduced viability. A viability and plant regeneration frequency of 95% was obtained after the meristems were in storage for one week in liquid nitrogen. From samples assayed after 8 weeks of storage in liquid nitrogen, more than 55% of the meristems regenerated into plantlets.

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A procedure has been developed to regenerate plants in high frequency from meristems of tomato (Lycopersicon esculentum Mill. cv. Starfire). Shoot apical meristems isolated from 7-day-old seedlings were aseptically cultured on a Murashige and Skoog (MS) medium supplemented with varying concentrations of cytokinins and auxins under defined environmental conditions. Benzyladenine (BA) or zeatin (Z) at various concentrations from 0.1 to 10 µm induced shoot differentiation in high frequency. All levels of BA or Z in conjunction with indoleacetic acid (IAA) also induced shoot differentiation. Whole plant regeneration occurred in media with hormone concentrations as follows: 1) BA and naphthaleneacetic acid (NAA) in the range of 0.1 to 1.0 µm, 2) 10 µm Z in conjunction with 1.0 µm NAA or vice-versa and 3) 10 µm IAA.