| The resource of Tilia Linn.is excellent greening tree which has straight shape,well crown type,heart-shaped leaves that turns yellow in fall.Tilia Linn.species are worldwide-distributed foliage trees.Linden are plant as foliage trees along the Under den Linden street which is famous for romance and graceful in the world.The resource of Tilia Linn.is distributed all oeer the world and concentrates in the north temperate zone.Now Tilia amurensis Rupr.and Tilia miqueliana Maxim are the main studying object in China.As for Tilia cordata,Tilia platyphylla,Tilia to,entosa and Tilia America which are widely erotized in the north area such as Shenyang,Dalian and so on,there is hardly research relevantly in China.The main factor effecting survival of exotic trees is the different climate condition from the producing area.In north area the mainly factor depends on whether the plant can survive the late spring cold and the low temperature in winter.So the study focusing on the difference of cold ability and cultivation measurement effects is a key point to apply the exotic Tilia species cold-resistance mechanisms,and of vital importance to provide a reference for popularize the tree plantation in north area.The research studied the cold-ability of exotic Linden in two periods.In early spring,branches at the bud bursting period and the leave outspreading period were tested under the laboratory cooling test.And the relationships between LT50 and physiological and anatomical characteristies were investigated.In autumn,we chose Tilia platyphylla as material to study the influence of cultivation measurement in fall.Coupling effects of water and fertilizers was designed according to appropriate condition of nutrient and fertilization of Tilia platyphylla.9 treatments were set combining 3 level of fertilization(40g/plant,60/plant,80/plant)and 3 level of the stop time of irrigating(Aug 30th,Oct 20th,Nov 10th).The effects on physiological and anatomical characteristics caused by different treatments were investigated.The resource of Tilia Linn.is excellent greening tree which has straight shape,well crown type,heart-shaped leaves that turns yellow in fall.Tilia Linn.species are worldwide-distributed foliage trees.Linden are plant as foliage trees along the Under den Linden street which is famous for romance and graceful in the world.The resource of Tilia is distributed all over the world and concentrates in the north temperate zone.Now Tilia amureosis and Tilia miqueliana are the main studying object in China.As for Tilia cordata,Tilia platyphylla,Tilia tomentosa and Tilia America which are widely erotized in the north area such as Shenyang,Dalian and so on,there is hardly research relevantly in China.The main factor effecting survival of exotic trees is the different climate condition from the producing area.In north area the mainly factor depends on whether the plant can survive the late spring cold and the low temperature in winter.So the study focusing on the difference of cold ability and cultivation measurement effects is a key point to apply the exotic Tilia species cold-resistance mechanisms,and of vital importance to provide a reference for popularize the tree plantation in north area.The research studied the cold-ability of exotic Linden in two periods.In early spring,branches at the bud bursting period and the leave outspreading period were tested under the laboratory cooling test.And the relationships between LT5o and physiological and anatomical characteristics were investigated.In autumn,we chose Tilia platyphylla as material to study the influence of cultivation measurement in fall.Coupling effects of water and fertilizers was designed according to appropriate condition of nutrient and fertilization of Tilia platyphylla.9 treatments were set combining 3 level of fertilization(40g/plant,60/plant,80/plant)and 3 level of the stop time of irrigating(Aug 30th,Oct 20th,Nov 10th).The effects on physiological and anatomical characteristics caused by different treatments were investigated.The results showed:1.The anti-cold regulating factors altered as the temperature changed,which was the main cause of the cold hardiness differences among the four genotypes.The regulation of the content of soluble sugar,proline and MDA was the major factor influencing the cold resistance at the bud bursting period.While at the leave outspreading period,cold hardiness was mainly influenced by lignification indicators and MDA relative variation.Moreover,there was a significant difference(P<0.05)in the cold hardiness among the four genotypes in both periods.2.Tilia tomentosa was the most resistant genotype during the bud bursting period while Tilia ameriea performed a stronger anti-cold ability at the later period.At the bud bursting period,the chilling injury temperature of Tilia cordata,Tilia platyphylla,Tilia america and Tilia tomentosa was-15.1??-17.4??-23.0??-20.8?,respectively,and 6.0??4.7??5.5 ? and 4.3 ?,respectively at the leave outspreading period.Considering the temperature situation at the two periods in Dalian,it is suggested that,there may not be freezing injury events at the bud bursting period,and measurements for preventing Linden trees from freezing or cold-induced injury should be implemented before the leave outspreading period.3.Osmotic adjustment and progress of lignification when exposure to cold environment is two ways responding to cold stress.The water-fertilizer effect can influence both course.In the research,anatomical characteristics and water stress were mostly effected by irrigation factor while physiological characteristics such as proline content and soluble sugar content were mainly effected by fertilization factor.Within the range of experiment design,water and fertilization promoted each other influencing the ratio of timbe,and there was alternative effect influencing the content of MDA and soluble sugar.Among all the cold effects,MDA and soluble sugar were the most sensitive to variation of fertilization,and anatomical characteristics such as branch water stress,proportion of cortex and xylem were more sensitive to irrigation factors.4.In a regular year,the most suitable conditions for cold ability were to stop irrigating at November 10th,and fertilized at the level of 80g/plant,under which treatment the brunches had the most soluble sugar,the lowest proportion of cortex and the highest value of the proportion of xylem.The following treatments that had quite high comprehensive index of cold hardness were stopping irrigating at November 10th,and fertilized at the level of 60g/plant,stop irrigating at October 20th,and fertilized at the level of 80g/plant.The thesis systematically study on the cold resistance ability of Tilia Linn.species in aspects of anatomical,osmotic adjustment,membrane mechanisms indicators,which was the first time in China.We figured out the mechanism of cold-resistance among the four species and the most suitable cultivation measurement of Tilia Linn.in autumn and winter.The study provided a theoretical basis for future popularization of Tilia Linn.species in north China area. |
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