A preliminary investigation into root-shoot growth relationships of lentils (Lens culinaris Medik)

An experiment was conducted in 1989/90 which examined the effects of irrigation and rhizobium inoculation on the growth of lentil cv. Titore. The plants were grown in 80 cm deep pots which enabled total recovery of roots. Results showed that lentils partition a large proportion of early photosynthate to the root, with root/shoot dry weight ratios at 32 days after sowing (DAS) of approximately 4.3. By final harvest, root/shoot ratio had declined to 0.36. Root/shoot ratio was not affected by the treatments. Root growth was analysed functionally using a Gompertz curve. Root dry matter (DM) accumulated rapidly with maximum growth rates of 16 g/m2/d. There were significant treatment effects on nodule score, final DM yield and seed yield. Fully irrigated plants produced 736 and 320 g/m2 of DM and seed respectively while non-irrigated plants produced 509 and 193 g/m2 of DM and seed respectively. Inoculation with Rhizobium leguminosarum gave a doubling of nodUle score at 46 DAS. However, by 56 DAS this difference had disappeared and all plants were well nodulated. The early difference in nodule score was accompanied by increased shoot production in the inoculated plants. However the increase was temporary and all plants produced similar shoot DM by 56 DAS.