Contribution of leaf lamina of grape nodal microcuttings to rooting, root vigour and plantlet growth in vitro

Abstract

Summary Significant effects of leaf lamina on early and higher percent rooting, root number, production of vigorous roots, and consequently healthy shoots and higher output of hardenable plandets were observed in vitro (MS medium containing 3% sucrose, 1.0μmol/L IAA, 0.1μmol/L GA 3 and gelled with 0.25% phytagel) using single node microcuttings (1.5–2.0 cm) of grape ( Vitis vinifera L.) ‹Arka Neelamani› and ‹Thompson Seedless› of four types, viz. petiole and leaf lamina removed ( P − L −), petiole retained-lamina removed ( P + L −), petiole and a segment of lamina retained ( P + Ls ), and petiole and full lamina retained ( P + L +). Retention of a segment of lamina was partly beneficial while keeping the petiole had no significant advantage over petiole removed cuttings. Comparative studies between P + L + and P + L − cuttings using media without auxin or sugar indicated the role of lamina as source of both of these factors. The P + L − cuttings did not respond favourably to higher auxin or sucrose but to supply of dextrose, a readily available energy source, suggesting a role of lamina in better utilisation of sucrose. Failure of P + L − cuttings to reach the level of performance of P + L + cuttings in terms of root and shoot vigour with higher IAA or sucrose, or with supply of dextrose, suggested that the lamina had an additional role as source of other rooting related factors/processes.