Effect of cold stratification and gibberellic acid on in vitro germination of Actinidia arguta and Actinidia chinensis
The effect of cold stratification (CS) and gibberellic acid (GA3) alone and in combination on in vitro germination of Actinidia arguta and Actinidia chinensis seeds was studied. Sterile seeds of the two plant species were stratified at 4°C for 28 and 42 days. Batches of stratified and non-stratified (control) seeds from both plant species were germinated on plant growth regulator-free Murashige and Skoog (MS) media and also on sterile filter paper bridges moistened with dH2O and GA3 concentrations of 500, 1000, 1500, 2000 and 2500 ppm. In the two plant species, seeds from the control and the CS treatments alone did not germinate on MS medium. However on filter paper bridges, seeds cold stratified for 28 days yielded only 8 and 20% germination percentage (GP) in A. arguta and A. chinensis, respectively, whereas CS for 42 days did not promote germination. In A. arguta, treatments of non-stratified seeds with GA3 resulted in 91% optimum GP at 1572 ppm GA3 and optimum 29 days mean germination time (MGT) at 1678 ppm GA3. In A. chinensis, 48% optimum GP and 24 days optimum MGT were achieved at 2225 and 2033 ppm GA3 concentrations, respectively. Cold stratification (28 days) followed by GA3 treatments of A. arguta resulted in optimum GP of 88% and 23 days optimum MGT at GA3 concentrations of 1435 and 1610 ppm, respectively. The same combined treatment of A. chinensis seeds yielded optimum GP of 80% and optimum 25 days MGT at GA3 concentrations of 1565 and 2050 ppm, respectively. In contrast, CS (42 days) followed by GA3 in A. arguta resulted in optimum GP of 99% and 27 days optimum MGT at GA3 concentrations of 1563 and 2120 ppm, respectively. Similar treatments in A. chinensis seeds yielded optimum GP of 45% and optimum 23 days MGT at GA3 of 998 and 1629 ppm, respectively. In conclusion, CS alone had little effect on germination, whereas CS (28 days) followed by GA3 significantly (p≤0.05) improved GP in both plant species. Treatments with GA3 alone and CS (42 days) followed by GA3 were more effective on germination of A. arguta than A. chinensis. Germinated seeds on moist filter paper can produce seedlings when sub-cultured on MS medium for seedling development.
Sekhukhune, M.K., Nikolova, R.V. and Maila, M.Y. (2018). Effect of cold stratification and gibberellic acid on in vitro germination of Actinidia arguta and Actinidia chinensis. Acta Hortic. 1204, 65-76
cold stratification, germination, in vitro, kiwi berries, physiological dormancy