Effects of pectolytic enzymes and oligogalacturonic acids on plant flowering

Stem apices of vegetating and flowering-induced long-day coneflower (Rudbeckia bicolor Nutt,) and short-day perilla (Perilla nunkitiensis (Lour) Decne) plants were shown to differ in cell wall compositions, the activities of enzymes degrading cell wall polysaccharides, and the compositions of their degradation products, especially pectins, We studied how the induction of flowering was affected by exogenous oligogalacturonic acids in coneflower (Rudbeckia) and perilla (Perilla) and by pectolytic enzymes in perilla, Flowering and stem elongation were induced in 27% of coneflower plants after five-day-long treatment with pentagalacturonic acid at 5 x 10(-6) M and in 51% after treatment with 5 x 10(-7) M. Treatment of coneflower apexes with 5 x 10(-6) and 5 x 10-7 M octagalacturonic acid induced stem formation in 76% of plants. Application of penta- and octagalacturonic acids to perilla plants under conditions unfavorable to flowering resulted in bud formation by day 40 after the beginning of the treatment in 63 and 100% of plants, respectively. Five-day treatment with 20 mu g/ml pectinase or Pectamacerin G10x from Penicillium digitatum under conditions unfavorable to flowering caused flowering in 50% of perilla plants. Combined treatment with pectinase preparations, as well as cellulase preparations G10x-I and G10x-II from Geotrichum candidum 3c and 3c-106 under the same conditions, resulted in 100% Perilla flowering.