14C-Labeled Photosynthates Translocation and Partitioning in Mycorrhizal Kinnow Plants (Citrus nobilis x C. deliciosa)

A pot culture experiment using steam-sterilized soil was conducted to study the translocation and partitioning of photosynthates in mycorrhizal Kinnow plants by direct feeding of (CO2)-C-14 in a plexi-glass chamber and the results was compared with uninoculated (non-mycorrhizal control) plants. One-year old Kinnow plants budded on Jatti Katti (Citrus jambhirt) were inoculated with Glomus manihotis, Glomus mosseae and Gigaspora gigantea separately and in combination, each with four replications. The distribution of radioactivity in the roots, shoots and leaves of mycorrhizal plants showed higher rate of recovery over the control. The maximum amount of labeled C-14 fixation in the root was observed with G manihotis followed by combined treatment, G mosseae and G gigantea with 81.5, 52.8, 32.3 and 21.6% more than the control respectively. The same pattern was followed in the leaves but with higher rate of total radioactivity recovery (23.9, 20.2, 13.2 and 4.7% more than control), and the difference between the treatments and the control was smaller. The results show that the rate of carbon assimilation, the export of photosynthates from the leaves, and the sink strength of roots increased in colonized plants compared with the control.