Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Growth relationships between root and shoot in walnut seedlings (Juglans regia L.). | 297s Ann. Sci. For. 1989 46 suppl. 297S-30ŨS Forest Tree Physiology etal. eds. Elsevier INRA Growth relationships between root and shoot in walnut seedlings Juglans regia L. . Frossard A. Charron and A. Lacointe Laboratoire de Bioclimatologie INRA Centre de Recherches de Clermont-Ferrand-Theix Domaine-de-Crouelle 63039 Clermont-Ferrand France Introduction It is well known that the periodicity of root growth throughout the year may be the same as or different from that of shoot growth Riedacker 1976 Kramer and Koslowski 1979 Frossard and Lacointe 1988 depending upon the species. It is difficult to interpret the published results because they were obtained on trees of different ages under different climatic conditions. It is particularly difficult to give precise answers to the following questions 1 is the relative position within the annual cycle of root and shoot growth a general characteristic of a given species In other words is there any evolution between years in the relative periodicity of root and shoot growth 2 are the relationships between variables describing growth equivalent throughout the year Answers to these questions are of particular interest when working on seedling growth and when investigating the carbon allocation to different organs Lacointe 1989 . Materials and Methods For 3 yr 1985 1986 1987 walnuts were sown in early June in clay soil and grown in a glass house. After 1 mo 10 seedlings per yr were transplanted into minirhizotrons and grown outdoors under natural conditions continental climate . Root and shoot growths were measured weekly during 2 yr for the 1985 and 1986 seedlings and during 1 yr for the 1987 seedlings. From September to March bud dormancy was studied using the MTB test Bailly and Mauget 1989 . Results There was a high variability between plants during both the 1st and the 2nd yr. An example of between yr variability is given in Figs. 1 1985-1986 and 2 1986-1987 . However the relative growth patterns of the .
