Dormancy of gladiolus corm. (IV)

The effect of auxin spray on breaking dormancy of gladiolus corm

Abstract

1) Previous works by the authors showed that many factors affected the dormancy of gladiolus corms. The present work reports three years experiments in 1955_??_1957 on the effects of auxin spary on breaking dormancy. The varieties used were as follows: For auxin spray, Bo Peep and Spot Light in 1955, Atom and Snow Princess in 1956 and Snow Princess and Spot Light in 1957. For tryptophane spary, Hector and Valeria in 1955, White Gold and Spot Light in 1956 and Snow Princess and Spot Light in 1957. As the rule, these corms were planted in early April and dug out in late September or October.
2) Auxin (10, 50 and 100 ppm of NAA) upon the leaf of gladiolus was applied once a week during its growth. After digging, the corms were treated at 35°C for 5 days and then at 0°C for 25 days. As the result, the high concentration of NAA inhibited the sprouting in general. However, NAA spray promoted the sprouting in some cases in the lots of temperature treatment. The higher concentrations of auxin were more effective in the earlier stage of dormancy, while the lower ones in the later stage.
The corms which were sprayed with NAA showed abnormal root formation and decreased propagation power. Namely, the weight of corm and number of spawn decreased.
3) Tryptophane which is considered to be the precursor of auxin in plant tissue was sprayed as in the case of NAA. In this case, the temperature treatment and addition of ascorbic acid were under-taken. In most cases, a slight promotion of sprouting was seen by the application of tryptophane. The lower concentrations were more effective in the later stage of dormancy as the case of NAA application.
4) The soaking of corms in the aqueous solution of NAA (10, 50 and 100 ppm) for four hours inhibits the sprouting of corms.