Mechanism of seed dormancy and its relationship to bud dormancy in Persian walnut

作者：Vahdati Kourosh^*; Aslamarz Asadolah Aslani; Rahemi Majid; Hassani Darab; Leslie Charles

来源：Environmental and Experimental Botany, 2012, 75: 74-82.

DOI：10.1016/j.envexpbot.2011.08.006

• Environment
• Dormancy
• Chilling
• Heat
• Seed
• Juglans regia

Stratification, chilling, and heat requirements for both seeds and buds of five Persian walnut genotypes were compared. In experiments carried out between November 2006 and March 2008, 1-year-old twigs were collected after leaf-fall, placed in plastic bags, and kept at 4 +/- 1 degrees C to provide chilling periods ranging from 400 to 1500 h. After chilling, twigs were transferred to a greenhouse for determination of chilling requirement and the number of growing degree hours (degrees C) needed for bud break. For germination experiments, mature seeds were stratified at 4 +/- 1 degrees C for treatment periods ranging from 0 to 8 weeks and then grown in a greenhouse under natural conditions. Germination rate and time to radicle emergence were recorded weekly and seedling heights were recorded after 2 months growth. Results indicated genotypes could be classified into three dormancy groups based on their chilling and heat requirements: low (%26apos;Ronde de Montignac%26apos; and %26apos;Serr%26apos;), medium (%26apos;Z(53)%26apos;), and high (%26apos;Lara%26apos; and %26apos;Z(63)%26apos;) dormancy. Stratification for 6-8 weeks was most appropriate to overcome walnut seed dormancy, to obtain the best germination percentage and germination rate, and to prevent physiological dwarfing. A relationship between the chilling and heat requirements for bud-break and the stratification requirement for germination of seeds was observed and data showed that the nutshell is a mechanical barrier to germination in walnut seeds with intermediate physiological dormancy.

• 出版日期2012-1