[Effects of temperature on leaf lettuce vernalization.]

Area of Science:

• Horticulture
• Plant Physiology
• Agricultural Science

Background:

• Vernalization is a crucial process for flowering in many plant species.
• Leaf lettuce varieties exhibit varying responses to temperature cues for floral induction.
• Understanding vernalization requirements is key for optimizing lettuce cultivation and yield.

Purpose of the Study:

• To investigate the impact of different early-stage temperatures on leaf lettuce vernalization.
• To determine the vernalization type of two specific leaf lettuce varieties (GB-30 and GB-31).
• To analyze the role of high-temperature stress in accelerating floral development.

Main Methods:

• Two leaf lettuce varieties (GB-30, GB-31) were subjected to 4°C, 20°C, and 25°C for 20 days.
• Subsequent high-temperature stress was applied to observe floral development.
• Paraffin section technology was used to examine flower bud differentiation.
• Bolting and flowering were monitored to assess vernalization and type.

Main Results:

• Both varieties showed varying degrees of bolting under high-temperature stress after initial temperature treatments.
• Early-stage temperatures induced flower bud differentiation in both varieties.
• 4°C treatment did not advance differentiation, but later high temperatures accelerated it.
• Developmental stages and effective accumulated temperatures varied significantly across treatments.

Conclusions:

• Leaf lettuce varieties GB-30 and GB-31 function as non-low temperature vernalization plants.
• High-temperature treatment significantly promotes bolting and flowering.
• Effective accumulated temperature from germination to blossom is approximately 2500°C·d for these varieties.