【作者】 张秀珍；

【导师】 邢世岩；

【作者基本信息】 山东农业大学 ， 森林培育， 2004， 硕士

【摘要】 苗木活力是指苗木正在表现的或潜在的进行正常生长、发育的能力。本文以平榛(Corylus heterphylla Fisch)和欧榛(Corylus avellana L．)为材料，研究了苗木在胁迫和正常条件下形态指标与生理指标的变化规律，并综合分析筛选出各种条件下的榛子的苗木活力评价指标，为榛子的苗木活力评价提供科学的理论依据。 试验分为休眠期和生长期两个时期进行。休眠期安排平榛的晾晒试验，生长期安排水涝试验和榛子的生长规律动态测定试验。试验研究结果表明： 1．在晾晒试验中，随着晾晒时间的延长，平榛的梢、茎、根、株含水量减小，枝条水势下降，栽植成活率降低，成活苗木的芽萌动时间推迟，生长量变小。严重失水苗即使芽萌动了后期也回缩，即使成活了失水对生长量和生物量也有明显的影响。利用相关分析和因子分析比较晾晒时间对各指标的影响程度，初步筛选出休眠期平榛苗木的活力评价指标：梢含水量、根含水量、枝条水势、成活率、新梢长和总萌芽数。苗木起苗期间，晾晒时间短，失水少时，用枝条水势可以更好的比较苗木的活力，晾晒时间过长，失水多时，则需用梢含水量和根含水量评定，并可利用成活率与含水量的回归方程预测栽植后的苗木成活率来进一步评价。栽植后的平榛苗木活力则需用实际成活率、总萌芽数和新梢长来评价。 2．生长期间的水涝试验表明，随着水涝时间的延长，榛叶内脯氨酸积累，根系电导率值升高，而根系活力和SOD酶活性在水涝初期上升，随着水涝程度的加剧，均逐渐的下降。这说明平榛虽对水涝胁迫有一定的适应性反应，但自身的调节能力有限，随着胁迫时间的延长，根系活力下降，细胞膜的选择透性损伤，活性氧清除能力下降。试验表明，榛子水涝16棒子苗木活力研究后，根系仍没有腐烂，苗株没有死亡，证明平棒的抗水涝能力很强。根据相关分析，筛选出电导率、脯氨酸和根系活力作为水涝期间的苗木活力评价指标。 3.根据生长期间的棒子形态指标的动态测定，对苗高和地径进行了年生长规律回归模拟，R在0.9以上，因而可用所得的回归模拟方程对苗木生长进行预测。棒子生长期间几种生理指标的动态变化规律并不一致，叶绿素a、叶绿素b和叶绿素总量呈现出“低一高一低”的变化趋势，可溶性糖则相反，呈“高一低一高”动态变化，SOD和可溶性蛋白质的动态变化基本上是双峰曲线，根据因子分析，将生理指标简化为较为独立的3个主因子，筛选出叶绿素总量、SOD比活力和可溶性蛋白质作为苗木活力评价指标。对两年生平棒的形态指标和生理指标进行相关分析和因子分析，筛选出苗高、地径、新梢长、新梢粗、叶绿素总量和SOD总活性作为该苗木的苗木活力评价指标，对欧棒的形态指标和生理指标做相关分析和因子分析，筛选出苗高、地径、主枝叶数、侧枝叶数和叶绿素a作为苗木活力评价指标。 4.根据休眠期和生长期的各种苗木活力指标的调查和分析，建立如下苗木活力评价体系:晾晒平棒的梢含水量和根含水量高于极限含水量48.15%和47.24%时，苗木保持一定的活力，栽植成活率可高于45%;低于梢含水量和根含水量的致死临界值20.58%和28.64%时，则苗木活力很低，栽植后不能成活;枝条水势的伤害临界值为一0.6MPa，低于该值，则苗木内在的生理会受到伤害，苗木活力下降;水涝胁迫时，平棒苗木的根系活力高于临界值49.SOOug/gFW·h时，苗木活力就会受到一定的伤害。更多还原

【Abstract】 Seedling vigor means a present or potential ability that the seedling can grow a nd d evelop n ormally. In t his a rticle, t he 1 aws o f morphological and physiological change of seedling under normal and threatening conditions were studied with the material Corylus heterphylla Fisch and Corylus avellana L. By comprehensive analysis, the indexes for evaluating filbert seedling vigor under different circumstances were selected. These indexes would provide scientific theoretical basis to judge the seedling vigor.This test was divided into two parts, dormancy phase and growing phase. In the dormancy phase, the experiment was done with the filbert drying in the air. In the growth phase, the waterlogging experiment was carried out and the dynamic rule of filbert developing was mensurated.The results were as follows:1. In the drying test, with the drying time prolonged, the water content in the shoot, stem, and root decreased; the plant surviving rate dropped; the budding time delayed and the growing amount reduced. If the seedling lost too much water, the buds would shrink in the later time. And even the seedling survived, the serious lack of water would have obvious effect on the growth and b iological q uantity. With t he c orrelative a nd factor a nalysis, all ndexes were contrasted and some indexes were selected to evaluate the vigor of the seedling. These indexes included water content of shoot and root, branch water potential, survival rate, shoot length and total buds. During the conservation of seedling, the less the time drying in the air, the less the water loss of plant, it was better to evaluate the vigor of seedling with the index branch water potential. If the drying time was too long and the plants lost too much water, the water content of shoot and root could be used to value the vigor of seedling.By the regression equation of survival rate with water content, the future survival rate could be predicted. And this survival rate might be used to evaluate the seedling vigor further. After the seedling were planted, it was necessary to use factual survival rate, total buds and the length of new shoot to value the Cory 1 us heterphylla Fisch seedling vigor.2. The results of waterlogging test showed that the content of proline in filbert leaves and the conductance rate of root increased with the time of threaten prolong. However, the root vigor and SOD rose at the earlier state, and then decreased when the waterlogging enhanced. These results indicated Corylus heterphylla Fisch could adapt the waterlogging condition in some certain degree, but its regulative ability was limited. During the course of waterlogging, root vigor dropped; the cell membrane was damaged and the capability to eliminate active oxygen decreased. After 16 days waterlogging stress, the root was still not rotten and the plant was not dead. This showed Corylus heterphylla Fisch had great ability to resist waterlogging. According to correlative analysis, conductance rate, content of proline and root vigor were selected to be the indexes to value seedling vigor.3. According to dynamic measuration of morphological indexes, regression simulation of yearly growing rule was done on seedling height and diameter. It was found that the coefficient of correlation was above 0.9, therefore, the trade of seedling growth could be forecast by regression equation. In the course of filbert growth, the metabolic laws of physiological indexes were different. The content of chlorophyll a, chlorophyll b and total chlorophyll varied as "low -high-low", on the contrary, the content of soluble sugar varied as "high-low-high". The dynamic variation of SOD and soluble protein presented as double apexes curve. By factor analysis, three main physiological indexes were chosen to value the seedling vigor. They were the content of total chlorophyll, comparable activity of SOD and solubleprotein. According to correlative and factor analysis on morphological and physiological indexes of two yearly Co\rylus heterphylla Fisch, seedling height,更多还原