Anatom ical Characteristics of Taxodium' zhongshansa 302'and Taxodium d istichum Wood

The tracheid properties and t issue ratio o f the juven ilew ood ofTaxod ium zhong shansha 302! andT. dis??tichum at breast heightw ere determ ined w ith m icroscope, and the variance of the properties betw een the tw o speciesand the radial var iat ion pattern w ere analyzed w ith GLM procedure o f SAS. The resu lts show ed that the average oftrache id leng th, w idth and length to w idth ratio ofT.' zhongshansha 302' were 2 737. 84??m, 44. 84??m and 60. 86respective ly, wh ich ofT. distichum w ere 2 698. 52μm, 43. 44μm and 61. 51 respect ively. The average of tangen??t ial trache id w all th ickness o f earlywood and latew ood o fT. zhongshansha 302! w ere respectively 5. 91μm and7. 57μm, fo rT. distichum the average o fw hich w ere 5. 89μm and 6. 54μm respectively. The average of tracheidw a ll to lum en ratio of earlywood and latew ood o fT. zhong shansha 302! andT. distichum w ere respectively 0. 15μmand 0. 35μm. The variance analysis ind icated that tracheid w a ll thickness of the latew ood o fT. zhongshansha302! w as significant ly th icker than the latewood o fT. d istichum at 0. 05 leve,l and other tracheid properties and a ll kinds of tissue rat io ofT. zhongshansha 302! did not sign ificantly d iffer from those properties ofT. d istichum. Thevar iance analysis also show ed that the tracheid leng th, w idth, length to w idth ratio, tangentia lw all thickness, tra??cheid tissue ratio, ray tissue rat io varied sign ificantly among annua l rings at 0. 05 leve.l T rache id w a ll to lumen ratioof earlyw ood and parenchym a tissue ratio d id not vary significant ly among annual rings at 0. 05 leve.l T racheidleng th, w idth, tangen tialw a ll thickness, tracheid t issue rat io o fw ood of the tw o spec ies increased greatly from thepith outw ard but ray tissue ratio decreased from p ith outw ard.