Spray application factors and plant growth regulator performance: I. Bioassays and biological response

✍ Scribed by Knoche, Moritz; Bukovac, Martin J.; Nakagawa, Shoichi; Crabtree, Garvin D.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 270 KB
• Volume: 54
• Category: Article
• ISSN: 1526-498X
• DOI: 10.1002/(sici)1096-9063(1998100)54:2<168::aid-ps800>3.0.co;2-q

✦ Synopsis

Bioassays were adapted to investigate e †ects of droplet size and carrier volume on performance of daminozide, gibberellic acid and 2,4-D using (GA 3 ) Phaseolus vulgaris L. as a model system. Response to plant growth regulators was indexed by inhibition (daminozide), promotion of internode elongation or ethylene production (2,4-D). Elongation of Ðrst plus second internodes (GA 3 ) above primary leaves was evaluated 14 days after treatment of primary leaves, while ethylene production was determined from head-space samples of incubated leaves 24 h after treatment. Daminozide inhibition of internode elongation was related to decreased cell size and number in pith and epidermis (range 49È70% of the untreated control).

increased cell size and number in both tissues 2É3-to GA 3 4É8-fold. Responsiveness to daminozide and 2,4-D markedly decreased as seedling age increased from 8 to 12 days, but responsiveness to increased. GA 3 Decreasing droplet size (10È0É5 ll) and increasing carrier volume (10È200 ll per leaf) at constant dose of daminozide (100 lg per leaf) and 2,4-D (100 lg per leaf) signiÐcantly increased performance, but had little e †ect on performance of GA 3 (2 lg per leaf). E †ects of application factors on performance were related to their e †ects on the interface area between droplets and leaf surface. SigniÐcant positive linear relationships were obtained between plant response and the logarithm of the droplet/leaf interface area for all growth regulators.