Exogenous nitric oxide donor sodium nitroprusside ameliorates root architecture and growth performance in young budding polybagged plants of rubber (Hevea brasiliensis)

Shoot die back condition has been observed in young budding rubber plants (Hevea brasiliensis Muell. Arg.) raised in polybags under hot and dry weather conditions in the recent past, partly due to failure of the root system, and therefore, it is imperative to find ways to improve the root system while enhancing other growth performances of rubber seedlings. In the present study, the effect of sodium nitroprusside (SNP) as a nitric oxide (NO) donor on root architecture and growth characteristics of polybagged rubber seedlings raised under glass house conditions and at two growth stages (one month and five months after transplanting) was investigated. In this communication, we report that exogenous application of SNP to rubber seedlings greatly induced lateral and feeder roots and root hair emergence and elongation, while improving primary root (tap root) growth and other growth characteristics of the shoot i.e., stem diameter, shoot height, leaf area and shoot and root biomasses in a dose-dependent manner. SNP concentration between 50 μM - 300 μM was found to be the best range. To our knowledge, this is the first report on exploring the effect of NO on root architecture and growth performance of rubber seedlings by exogenous application of SNP.