【作者】 左宝峰；

【导师】 姚延梼；

【作者基本信息】 山西农业大学 ， 森林培育， 2005， 硕士

【摘要】 本文以生长发育良好的10年生雪松扦插苗木为试验材料,分析研究了低温胁迫下雪松叶绿素(Ch1)、类胡萝卜素(Car)、相对电导率、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙二醛(MDA)、可溶性糖(Sug)等各项生理生化指标的变化规律。结果表明:(1)、雪松叶绿素a含量随着温度的下降而迅速降低,叶绿素b含量保持相对稳定,而类胡萝卜素随着温度的降低反而缓慢升高,通过这种自我保护作用,降低了低温对雪松苗木的伤害。(2)、随着气温的下降,雪松苗木相对电导率在增强,丙二醛含量也在显著提高,这表明低温使雪松细胞膜结构破坏,胞内组分外渗,代谢紊乱。(3)、雪松超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性在自然降温过程中均呈“M”状变化。自然降温过程中,它们作为保护性酶,与雪松抗寒性密切相关,是雪松抗寒性的基础条件之一。(4)、在低温胁迫下,雪松叶片细胞中可溶性糖含量随温度降低而不断升高,这是对低温环境的一种保护性反应。细胞中可溶性糖含量增加增强了细胞的渗透调节能力,同时也降低了冰点,从而提高了雪松的抗寒能力。(5)、低温对处理的各项生理生化指标的影响明显降低,这说明在采取保护措施后低温对雪松苗木的危害程度也显著降低。这是由于采取保护措施后改善了雪松生长的外部的小环境,使雪松苗木避免遭受极端气候条件影响,从而保护了雪松苗木,并促使其逐渐适应这种极端气候条件,为雪松北方引种的成功奠定基础。更多还原

【Abstract】 This paper reviews the variable rules of SOD 、 CAT、 MDA、 Carotene、 Relativity-conductance and chlorophyll in the 10-year old seedlings of cedar which have good health , under the cold stresses. The results show that: [1] With the temperature decreasing , the content of chlorophyll a has increasing trend , however, the opposite to the carotene ,but the chlorophyll b kept stable, which all show that the cedar avoided the cold stress through this self-protection. [2] With the temperature decreasing . the conductance and MDA have increasing trend ,this reviews the cold stress made the destroy of cell membrane , which lead to the foul up of metabolism. [3] With the temperature decreasing, the change of SOD and CAT both show the shape of "M" , they are one of the basic conditions relating to the cold stress of cedar.[4]During the cold stresses, the content of amylose in cedar cells has increasing trend with the temperature decreasing, which can be seen a protective reaction to the cold situation. The improvement of controlling capability on permeability can be attributed to the increase of amylose in cells, which can also decrease the freezing point, so as to improve the cedar resistance to the cold. [5] We find the effect of cold stress can be decreased , so it reviews the effect of the cold stress on cedar can be decreased after taking certain disposals . In all, the cedar avoided the effect of extreme climate after taking certain disposals which can change its microenviroment, so that it can protects itself and adapts to this extreme condition, which all contribute to the successful introducing of cedar to the north.更多还原