不同贮藏条件下小麦和玉米种子的水分变化规律及其建模验证

种子平衡水分(EMC)是评价种子吸湿或解吸动态变化的重要指标。本研究以不同初始水分(IMC)小麦和玉米种子为试材，研究了不同贮藏条件下的吸湿解吸规律，并建模验证。结果表明，玉米种子在8.0%IMC、15℃、相对湿度(RH)<18.8%， 25°C或40℃和RH<48.1%条件下; 以及在13.5%IMC或18.0%IMC、15°C、25°C或40℃、RH<48.1%条件下呈解吸变化; 而在其他条件下均呈吸湿变化。小麦种子在贮温15、25和40℃时，8.0%IMC在RH≤18.8%、18.0%IMC在RH≤48.1%时解吸，其他条件下吸湿; 13.5%IMC在15℃和RH<48.1%以及25、40℃和RH<18.8%时解吸，其他条件下吸湿。小麦种子在15℃和RH=53.0%、25℃和RH=48.0%以及40℃和RH=43.0%时的安全水分(SWC)依次为13%、11%和9%; 玉米种子在15℃和RH=55.0%、25℃和RH=50.0%以及40℃和RH=40.0%时，其SWC依次为14%、12%和9%。小麦种子EMC在15℃和RH>50.0%、25℃和RH>50.0%、40℃和RH>48.0%时超过其对应条件下的SWC; 玉米种子EMC在15℃和RH>50.0%、25℃和RH>47.0%以及40℃和RH>47.0%时超过其对应条件下的SWC。玉米郑单958的平衡时间(d)与IMC(x)、RH(y)和温度(z)的预测模型为d = 35.34 + 4.32x - 0.28y - 0.35z - 0.031xy - 0.012xz - 0.0011yz + 0.003y²，农大108为d = 39.76 + 2.35x - 0.39y - 0.27z - 0.022xy - 0.014xz - 0.0057yz + 0.008y²，小麦山农15为d = 25.69 + 7.65x - 0.27y - 0.89z - 0.12xy - 0.07xz - 0.007yz + 0.006y²+ 0.04z²，泰农18为d = 46.67 + 0.39x - 0.28y - 1.72z - 0.006yz + 0.006y²+ 0.017z²。模型经验证，预测性良好。

Moisture Variation and Model Verification of Wheat and Maize Seeds under Different Storage Conditions

Seed equilibrium moisture is an important indicator for evaluating the dynamic changes of seed moisture absorption or moisture desorption. The laws of the seed moisture absorption or moisture desorption under different storage conditions were studied using two maize (Zea mays L.) cultivars and two wheat (Triticum aestivum L.) cultivars with different initial moisture contents (IMC). Simulated models were established accordingly for each cultivar and verified with independent data. The moisture desorption was observed in 8.0% IMC maize seeds under the conditions of 15°C and RH < 18.8%, 25°C and RH < 48.1%, 40°C and RH < 48.1%; or in 13.5% and 18.0% IMC seeds under the conditions of 15°C and RH < 48.1%, 25°C and RH < 48.1%, 40°C and RH < 48.1%; and moisture absorption was observed under other storage conditions. Wheat seeds stored under 15°C, 25°C, and 40°C showed moisture desorption when RH ≤ 18. 8% for 8.0% IMC seeds or RH ≤ 48.1% for 18.0% IMC seeds; the 13.5% IMC seeds stored under the conditions of 25°C and RH < 18.8%, 25°C and RH < 18.8%, 40°C and RH < 18.8% showed moisture desorption; and wheat seeds stored under other storage conditions presentedmoisture absorption. The safe water contents (SWCs) of wheat seed were 13% under 15°C and RH = 53.0%, 11% under 25°C and RH = 48.0%, and 9% under 40°C and RH = 43.0%. The SWCs of maize seed were 14% under 15°C and RH = 55.0%, 12% under 25°C and RH = 50.0%, and 9% under 40°C and RH = 40.0%. The equilibrium moisture contents (EMCs) of wheat seed were higher than the corresponding SWCs under the same condition of 15°C and RH > 50.0%, 25°C and RH > 50.0%, 40°C and RH > 48.0%, and the equilibrium moisture contents (EMCs) of maize seed were higher than the corresponding SWCs under the same condition of 15°C and RH > 50.0%, 25°C and RH > 50.0%, 40°C and RH > 47.0%. The predictive models of equilibrium time (d) for seeds were simulated on the basis of IMC (x), RH (y), and temperature (z). The equations were as follows: d = 35.34 + 4.32x - 0.28y - 0.35z -0.031xy - 0.012xz - 0.0011yz + 0.003y² for maize cultivar Zhengdan 958, d = 39.76 + 2.35x - 0.39y - 0.27z - 0.022xy - 0.014xz - 0.0057yz + 0.008y² for maize cultivar Nongda 108, d = 25.69 + 7.65x - 0.27y - 0.89z - 0.12xy - 0.07xz - 0.007yz + 0.006y²+ 0.04z² for wheat cultivar Shannong 15, and d = 46.67 + 0.39x - 0.28y - 1.72z - 0.006yz + 0.006y²+ 0.017z² for wheat cultivar Tainong 18. The predictive values based on these models were highly consistent with the tested values, indicating the good applicabilities of these models.