低温胁迫下茶梅‘小玫瑰’（Camellia hiemalis ’ShiShi Gashira’）生理生化变化的研究

【作者】 徐康；

【导师】 夏宜平；

【作者基本信息】 浙江大学 ， 园林植物与观赏园艺， 2003， 硕士

【摘要】 茶梅是江浙一带重要的秋冬季花灌木，四季常绿、花期长，在园林建设中具有广阔的应用前景，但目前国内对于茶梅的抗寒生理尚缺乏研究。本文以茶梅的常用品种‘小玫瑰’（Camellia hiemalis’ ShiShi Gashira’）为试材，较系统地研究了低温胁迫下其植株的生理生化变化，为茶梅园林应用的品种选择和树种北移提供了理论和试验依据。试验结果表明： 1、叶片的电解质外渗率（REC）的变化是茶梅低温胁迫后较为稳定的生理指标。通过设置不同处理低温和不同处理时间，均证明‘小玫瑰’在低温胁迫下其叶片的原生质膜受到损伤和破坏，膜透性增大，电解质的外渗量激增。-10℃以下的低温处理能明显地造成茶梅叶片的冻害，处理2小时后叶片REC从最初的13％激增到22％，24小时后达31％，48小时后就达35％；-20℃处理6小时后叶片REC从最初的13％剧增到46％，24小时后即高达51％。表明茶梅叶片在低温胁迫下，随着时间的延长其原生质的膜透性逐渐增大。 2、将在不同处理时间不同低温处理下测定的REC变化作曲线，并结合Logistic方程分别计算茶梅的半致死温度(LT₅₀)。发现在低温处理6小时以上，茶梅叶片的REC均随着处理温度的降低而呈“S”形上升，由此可以计算出“S”形拐点对应的温度——即茶梅叶片组织的半致死温度，结果为-12.5℃至-14℃之间，这可认为是茶梅抗寒能力的重要指标。 3、不同低温胁迫下，茶梅叶片内的含水量均随着处理时间的延长而呈逐渐缓慢降低的趋势。但同时，茶梅叶片内可溶性糖的变化则呈缓慢上升的趋势，以通过提高细胞液的浓度从而提高抗寒性。如-5℃处理的4天内叶片可溶性糖含量变化不大，但6天后上升较快，从最初的可溶性糖含量68.23mg／100g增加到8天后的90.02mg／100g。 4、低温胁迫下茶梅叶片内脯氨酸含量的变化与低温的关系不甚明显。0℃处理后脯氨酸含量呈上升趋势，24小时后叶片脯氨酸含量从1.2μg／g升至2.2μg／g，48小时后增加到29.7μg／g，72小时后则降至12.02μg／g；-20℃处理，24小时后脯氨酸含量从6.1μg／g降至4.6μg／g，48小时后又增加至18.6μg／g。其内在原因有待进一步研究。 5、不同低温胁迫下，茶梅叶片的有关膜质过氧化的酶活性呈现不同的变化规律。低温处理前4天超氧化物歧化酶（SOD）活性逐渐增加，4天后随着处理时间延长SOD活性逐渐降低。如上 处理2天后SOD活性从20．lunit飞－‘上升到 30．3unit·g－’，4天后又升至 45＊unit·g－‘，6天后下降到 32．lunit·g’，但 8天后骤降到 26．7unit．g叫。茶梅叶片过氧化氢酶（CAT）活性的变化，随不同低温处理而不同。如 ooC处理 2天至 4天内 CAT活性从 197．74 mgHzoz℃’·min‘增力至250mg H。O。·g‘·min’，6天后开始下降至187．58 mg H。O。·g’·min叫，8天后则又迅速增加到359mg H。O／g叫·min叫；但九5t处理2天后叶片CAT活性先急剧下降，4天至 6天后又增加到 29．65 mg H。O广 g叫·min’，8天后却又开始迅速下降。 本文对茶梅低温胁迫下叶片生理生化的变化进行了讨论，并结合实验结果分析了适合茶梅的抗寒性指标。主要结论是：REC是衡量茶梅抗寒性的理想指标；不同低温下REC结合LOgistiC方程可以计算茶梅的半致死温度LT”，可作为衡量茶梅抗寒力的重要指标；叶片内可溶性糖含量、游离脯氨酸含量可以作为茶梅抗寒性的相关指标。更多还原

【Abstract】 Camellia hiemalis is an important shrub of winter florescence in eastern China. For evergreen and long period of blooming, it will be widely used in gardens. It is necessary to study physiology of cold resistance for selecting culture varieties and their extension to northern China, but few researches are found about this area. In this paper, with various treatments of low temperatures, the characteristics of physiologic and biochemical of C. sasanqua were determined in Camellia hiemalis ’ShiShi Gashira’, which is a very common culture variety in used now. The results are as below:1. The relative Electric Conductivity (REC %) was regarded as the reliable physiological indication for tolerance to low temperature in leaves of C. hiemalis. In different levels of low temperature and treatment period, it was confirmed that the cell membrane of ’ShiShi Gashira’were injured under low temperature, and REC increases sharply. The leaves obviously frozen stiff after two hours storage with temperature below -10 in C. hiemalis . Meanwhile, the REC increased from 13% to 22%, and reached to 31% 24 hours later, and up to 35% after 48 hours. With the treatment of -20 , REC increased dramatically from 13% to 46% after 6 hours, and to 51% 24 hours later. It showed that the leakage of electrolyte in cell membrane gradually increased as the response of low temperature in C. hiemalis .2. REC increasing curves were described depended on the different levels of low temperature and treatment period. Following these REC curves and logistic equation, we calculated the LTso of C. hiemalis . The "S" shaped increasing curves of REC was found for the treatments storage longer than 6 hours with the temperature dropping. From the inflexion of "S" curve, we could calculate theof C. hiemalis ’ShiShi Gashira’. And we suggested -12.5 to -14 as the LT50 which considered as an important guideline of cold tolerance in C. hiemalis .3. Along with the storage in low temperature, the water contents decreased slowly in leaves of C. hiemalis. Meanwhile, the unmarked increase for concentrations of soluble sugar was found which indicated the thickness of cell liquid could enhance the cold resistance. For storage in -5 , the concentrations of soluble sugar in leaves changed slightly in first 4 days, but increased sharply 6 days later, and up to 90.02mg/100g at 8th day compared to the stared concentration as68.23mg/100g.4. There was no obvious relationship between the concentrations of free proline and low temperature in leaves of C. hiemalis. Stored at 0 , the free proline contents increase from 1.2 g/g to 2.2 g/g one day later, and reached 29.7 g/g in the second day, then dropped to 12.02 g/g 72 hours later. At -20 , it decreased from 6.1 g/g to 4.6 g/g one day later, but increased to 18.6 g/g in the second day. It needs further researches to explain.5. As the response of low temperature, the activity of enzymes about peroxidation of cell membrane showed different results. The activity of SOD gradually enhanced in the first 4 days, but decreased later. For example, at -10 the SOD activity for increases from 20.1 to 30.3 unit g-1 in first two days, and reached 45.0 unit g-1 at 4th day, but dropped to 32.1 unit g-1 6 days later, and continued down to 26.7 unit g-1 at 8th day. The CAT activity showed increase from 197 to 250 mgH2O2 g -1 min-1 in first 2-4 days at 0 storage in C. hiemalis, but decreased to 187.58 mgH2O2 g-1 min-1 at 6th day, and then increased dramatically to 359 mgH2O2 g-1 min-1 8 days later. Different results showed at the storage in -15 , the CAT activity dropped quickly from 289.4 to 138.9mgH2O2 g-1 min-1 after 2 days, but up to up to 205.83 mgH2O2 g-1 min-1 4 days later, and reached to 291.65 mgH2O2 g-1 min-1 at 6th day, then fell again as 202.1 mgH2O2 g-1 ’min’1 at 8th day.Based on the discussions about the physiological and biochemical changes in leaves of C. hiemalis stressed on the low temperature, the suitable indicator for cold tolerance was suggested in the pa更多还原