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不同温度沙藏层积处理对闽楠和桢楠种子萌发及生理特性的影响
Germination and Physiological Characteristics of Phoebe bournei and Phoebe zhennan Seeds During Sand-stored Stratification at Different Temperatures
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摘要: 以闽楠与桢楠种子为试验材料,模拟闽楠、桢楠分布地冬季(4 ℃)和春季(16 ℃)平均温度设置将种子沙藏层积处理,测定种子在沙藏层积过程中发芽率、贮藏物质含量、抗氧化能力等指标,探究种子休眠解除过程中生理生化变化规律,分析不同温度沙藏层积处理对闽楠与桢楠种子萌发及生理特性的影响。结果表明:闽楠种子在16 ℃与低温4 ℃层积下发芽率最高分别达到86.7%与62.5%,桢楠种子发芽率达到93.3%和72.5%,显著高于未沙藏层积的种子,发芽率分别为12.5%(闽楠)和57.5%(桢楠);种子淀粉含量均呈阶梯式下降,可溶性蛋白含量0~25 d急剧下降后趋于平缓,且16 ℃层积处理下淀粉和可溶性蛋白消耗量均大于4 ℃,可溶性糖含量在层积100 d时大量消耗;抗氧化酶活性均在层积中后期达到较高水平,其中SOD、POD活性动态变化均表现为持续上升后下降,二者呈极显著正相关,CAT活性初期呈下降趋势,与MDA含量呈显著负相关;层积过程中发芽率与层积时间、贮藏物质均呈显著相关性水平。综上所述,层积处理可有效提高种子发芽率且暖温层积处理休眠解除效果优于低温层积处理;前期同等条件下桢楠种子发芽率显著高于闽楠,层积中后期差距缩小;16 ℃层积处理下种子主要贮藏物质转化率高于4 ℃,更有利于种子萌发时物质能量的供给;沙藏层积75~100 d的闽楠和桢楠种子发芽率较高且抗氧化酶活性较强,取该时段的种子播种,辅以适宜的栽培管理,能有效提高出苗率。Abstract: The seeds of Phoebe bournei and Phoebe zhennan (precious tree species) are characterized by hard seed coats and physiological dormancy. To investigate the effects of sand stratification at different temperatures (16 ℃ and 4 ℃) on seed germination and physiological characteristics of these two species, this study used their seeds as experimental materials. Indicators including germination rate, storage substance content, and antioxidant capacity were determined during sand stratification. The objectives were to identify effective stratification methods for breaking seed dormancy and to explore the physiological and biochemical changes during dormancy release. The results showed that the maximum germination rates of P. bournei seeds under warm (16 ℃) and cold (4 ℃) stratification reached 86.7% and 62.5%, respectively,, while those of P. zhennan seeds were 93.3% and 72.5%. These rates were significantly higher than those of non-stratified seeds, which were 12.5%(P. bournei)and 57.5%(P. zhennan), respectively. Starch(ST)content in both species decreased in a stepwise pattern. Soluble protein(SP)content declined sharply from 0 to 25 days before leveling off. Under 16°C stratification, both ST and SP consumption exceeded those at 4°C. The soluble sugar(SS)content was substantially consumed at 100 days of stratification. Antioxidant enzyme activities reached higher levels during the mid-to-late stratification phase. Superoxide dismutase(SOD) and peroxidase(POD)activities exhibited sustained increases followed by decreases, showing a highly significant positive correlation. Catalase(CAT)activity initially declined and was significantly negatively correlated with malondialdehyde(MDA)content. Germination rates during stratification showed significant correlations with stratification duration and stored substances. In summary, Stratification treatment can effectively improve seed germination rate, with warm-temperature stratification showing better dormancy-breaking efficiency than cold stratification. Under identical initial conditions, P. zhennan seeds exhibited significantly higher germination rates than P. bournei, though this gap narrowed during the middle and late stratification phases. At 16°C stratification, the conversion rate of primary storage substances was higher than at 4°C, better supporting material and energy supply during seed germination. Seeds of both species exhibited higher germination rates and stronger antioxidant enzyme activity after sand-stratification for 75–100 days. Sowing seeds within this period, supplemented with appropriate cultivation management, can effectively improve seedling emergence rates.
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