| Root system plays an important role in the whole growth and development of plants,The water and nutrients needed for plant growth are mainly obtained by fine roots from the soil.Root growth is the result of the interaction of tree species characteristics with soil environmental factors,Root system research can provide scientific basis for adaptive evaluation of difficult habitat tree species.Ma Dong(Quercus acutissima Carr.)belongs to the genus of Fagaceae,and has the characteristics of strong adaptability,drought resistant barren,rapid growth and strong sprout etc.It is widely used and has the functions of soil improvement,corrosion prevention,slope protection,water conservation and protection.This paper takes Q.acutissima forest which is in Yaoxiang,Shandong province as the object,the sawtooth oak plantations plots buried in the micro root canal,root of Q.acutissima annual growth dynamics to carry out continuous observation and survival analysis.The main research provenances in Rocky Mountain shallow root biomass,root morphology,root longevity and its relationship with soil nutrients,in order to reveal the northern Rocky Mountain Forest of Q.acutissima root growth characteristics and environmental suitability to provide theoretical basis for the selection and management of man-made forest plantations.According to the characteristics of shallow root tree species,in the North rocky mountain afforestation,can consider the root growth strategy and adopt appropriate cultivation and management measures,so as to make up the trees on different limiting factors of defects,to achieve higher survival rate and preservation rate of vegetation.The results show that:(1)In Q.acutissima plantation of different diameter root,fine root biomass in different provenances.Overall,the biomass of root system mainly focus on 0-0.5cm and 1.0-2.5cm.Fine root biomass of Q.acutissima is 220.03g,319.72g,respectively.The fine root biomass of diameter range to the highest proportion of 1.0-2.5cm.The fine root biomass in the 0-0.5cm diameter range is at least 220.03g.They are only 27.677%of the biomass in the 1.0-2.5cm diameter range.(2)The morphology in different root diameter has difference to some extent.In root length,there is a significant difference in root length between different diameter classes(P<0.05).With the increase of root diameter,the length of roots decreased gradually,and the difference is obvious.For root surface areas,within the 0.5-1.Ocm and 1.0-2.5cm diameter ranges,the surface area of roots is significantly larger than the surface area of 0-0.5cm diameter(P<0.05),the root surface area of 0-0.5cm diameter is significantly larger than the surface area of 2.5-4.0cm diameter range.For number of root tips,the number of root tips in the 0-0.5cm diameter range averaged 182.The root tips are significantly larger than those of the other three diameter classes(P<0.05).With the increase of root diameter,the number of root tip is decreased obviously.(3)In the 3 seasons,there are significant differences in the number of fine roots,and with the increase of time,the number of living roots decreased significantly,and the number of dead roots increased.The number of living roots in spring(209)is about 1.80 times of the number of living roots in summer(146),and is about 5.81 times the number of autumn(36).The number of dead roots in autumn(92)is significantly greater than that in spring(43)and summer(23),and is 2.14 times as many as in the spring and 4 times in summer.In the total number of roots,the number of fine roots in spring is much larger than in summer and Autumn.The total fine roots in spring(252)are 1.81 times of the total fine roots in summer(139)and 1.97 times in autumn(128).But there are no significant differences in fine root numbers between summer and autumn.(4)Q.acutissima roots are classified according to different diameter.In the three seasons,the root length decreased with the increase of root diameter;The root length of different diameter classes in autumn is significantly greater than that in summer and Autumn;and the root length of different root diameter range in summer is significantly higher than that in spring.In the range of 0-0.5cm diameter,there are significant differences in root length between the three seasons,the root length in autumn is significantly higher than that in summer,the root length in summer is significantly higher than that in spring(P<0.05).In the 0.5-l.Ocm diameter range,the root length in summer and autumn is significantly higher than that in spring,but there is no significant difference between summer and autumn(P<0.05).Witihin the diameter range of 1.0-2.5cm,the root length in autumn is significantly greater than that in spring and summer(P<0.05),within the diameter range of 2.5-4.0cm,the root length in autumn is significantly greater than that in spring and summer,and the root length in summer is significantly higher than that in spring(P<0.05).(5)With prolonging survival time of roots,the cumulative survival rate of fine roots decreases,fine roots gradually grow old and die.root average life is 99d,the median life is 97d.There are significant differences in the survival rate of fine root in different seasons(P<0.05).The survival rate of fine root in spring is higher than that in autumn and summer and its life is longer.There is a significant difference in root survival between spring and autumn and summer(P<0.05).The difference between summer and autumn in 0-1OOd range is significant,and summer is significantly longer than autumn,however,there is no significant difference in survival rate of fine root in 100-160d range.(6)With the correlation analysis showed,the root biomass and soil nutrient(organic matter)shows a significant positive correlation(r=0.914).There is a negative correlation between root length and soil organic matter(r=-0.809).The whole P and root diameter shows significant positive correlation(r=0.946).The organic matter has a significant negative correlation with the root surface area(r=-0.831).The fine root longevity(i.e.oak survival time)is significantly affected by the P.There is a significant positive correlation between the survival time of fine roots and total P content(r=0.831). |
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