Modification by gibberellin of the growth-temperature relationship in mutant and normal genotypes of several cereals

✍ Scribed by J. L. Stoddart; E. J. Lloyd

• Publisher: Springer-Verlag
• Year: 1986
• Tongue: English
• Weight: 517 KB
• Volume: 167
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00391340

✦ Synopsis

High-resolution growth measurements were conducted using a linear variable displacement transformer in conjunction with a temperature-programmed meristem-cooling collar. Chilling and rewarming profiles were determined for a range of Gramineae, in the presence and absence of varying concentrations of gibberellic acid (GA3). In wheat (Triticum aestivum L.) seedlings, the growth-constraining temperature (Pc) was progressively lowered by increasing GAa concentration, with a difference of -4.8 ~ C between controls and material treated with 10-4M GA3. Dwarf-5 maize (Zea mays L.) seedlings had a higher Pe than tall segregates and the difference was markedly reduced by exposure to a saturating concentration of GA3. A similar effect was observed with Tanginbozu dwarf rice (Oryza sativa L.). The growth ratetemperature responses of Rht3 gibberellin-insensitive dwarf wheat seedlings were unaffected by GA3 and the P~ values for these segregates were around 5~ higher than for normals. Slender (sl) barley (Hordeum vulgare L.) genotypes had Pc values of -7 ~ C, compared with + 4 ~ C for wild-type material, and did not show positive hysteresis for growth rate during the rewarming phase. These studies indicate that GA3 modifies the thermal sensitivity of meristem function in Gramineae in a manner which enhances low-temperature growth.