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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #189823

Title: Growth patterns and morphology of fine roots of size-controlling and invigorating peach rootstocks

Author
item BASILE, B
item Bryla, David
item SALSMAN, MICHELLE
item MARSAL, JORDI
item CIRILLO, C
item JOHNSON, SCOTT
item DEJONG, T

Submitted to: Tree Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2006
Publication Date: 11/1/2006
Citation: Basile, B., Bryla, D.R., Salsman, M., Marsal, J., Cirillo, C., Johnson, S.R., Dejong, T.M. 2006. Growth patterns and morphology of fine roots of size-controlling and invigorating peach rootstocks. Tree Physiology. 27:231-241. Available: http://heronpublishing.com/tree/pdf/volume27/27-231.pdf

Interpretive Summary: This study demonstrated that peach rootstocks with different vigor have similar seasonal patterns of fine root production. Growth of the fine root system decreased during the major period of fruit growth. This phenomenon was more pronounced in dwarfed trees in which competition among growing organs may be more severe because of a smaller carbon pool. Independent of rootstock, roots produced during spring had high specific root length, which suggests an opportunistic root growth strategy at the beginning of the growing season. In addition, the results of the present study seem consistent with the previous hypothesis that peach rootstocks control tree size by modifying tree water status. The thicker fine root system of K146-43 may be related to its lower hydraulic conductance compared to Nemaguard. However, anatomical studies of K146-43 fine roots are still needed to better understand potential differences in the radial pathway of these roots compared to more vigorous rootstocks.

Technical Abstract: The purpose of the present study was to compare growth patterns and morphology of fine roots of size-controlling and invigorating peach rootstocks. The peach trees used in the field experiment were grafted on five different rootstocks: a vigorous control (Nemaguard), three intermediate vigor rootstocks (K119-50, P30-135, and Hiawatha), and a semi-dwarfing rootstock (K146-43). Minirhizotron tubes were installed at the base of trees on each rootstock and root images were captured nondestructively using a minirhizotron digital camera system. Number, visible length, and diameter of new roots were recorded at fixed soil depths from 19 April 2000 to 19 December 2001. Root diameter, specific root length, root tissue density, and root length density were also measured periodically for each rootstock on roots collected from in-growth cores. Rootstocks had similar seasonal patterns of new root production. Fine root production was lowest in winter and also appeared to decline during the final stages of fruit growth. The rootstock with almond in its genetic background (K119-50) had the most fine root production and had the greatest concentration of new roots below 70 cm, whereas there were no differences among the other four rootstocks in the total number of roots produced. K146-43 had thicker fine roots than the other rootstocks. Independent of rootstock, roots produced during spring had greater specific root length than later in the season. Seasonal patterns of fine root production did not appear to be associated with the dwarfing effect of each rootstock, though thicker fine roots of the most dwarfing rootstock (K146-43) may be related to lower hydraulic conductance capacity.