Dormancy of safflower seeds: effect of storage and cold stratification

Abstract: Safflower seeds exhibit dormancy soon after dispersion from the mother plant, making it impossible to sow newly harvested seeds. Thus, the aim of the present study was to evaluate breaking the dormancy of safflower seeds during storage associated with the use of different periods of cold stratification. Seeds with a moisture content of 7.2% were stored for 0, 60, 120, 180, and 240 days, and for each storage period, they were stratified for 0 (control), 1, 2, 3, 4, 5, 6, and 7 days at 10 °C in the dark. After stratification, seeds were subjected to the germination test and evaluated for percentage of root protrusion, germination speed index, and percentages of first count and final count of normal seedlings. Safflower seeds gradually overcome dormancy during storage for 240 days in a non-controlled environment. Storage associated with periods of cold stratification for 5 to 7 days lead to an increase in germination and are effective in breaking the physiological dormancy of safflower seeds.摘要：红花种子自母株脱落之后便迅速进入休眠状态，导致新收获的种子无法直接用于播种。为此，本研究旨在评估贮藏过程中结合不同时长低温层积（cold stratification）处理打破红花种子休眠的效果。本实验选取含水量为7.2%的红花种子，分别设置0、60、120、180、240天共5个贮藏时长；针对每个贮藏时长组，在10℃黑暗环境中分别进行0（对照组）、1、2、3、4、5、6、7天的低温层积处理。层积处理完成后，对所有种子开展发芽试验，测定指标包括胚根突出率、发芽速度指数、正常幼苗初次计数百分率及最终正常幼苗百分率。结果表明，在非受控环境中贮藏240天的过程中，红花种子的休眠会逐步得到解除；结合5~7天低温层积的贮藏处理可显著提升种子发芽表现，能够有效打破红花种子的生理休眠。