Exogenous nitric oxide donor sodium nitroprusside ameliorates root architecture and growth performance in young budding polybagged plants of rubber (&lt;em&gt;Hevea brasiliensis&lt;/em&gt;)

N M C Nayanakantha,P D Pathirana,A M W K Senevirathna,P Seneviratne

doi:10.4038/jrrisl.v94i0.1821

Abstract

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.

Highlights

The standard practice adopted in the commercial propagation of rubber (Hevea brasiliensis) clones is by grafting buds of selected clones on to unselected seedling rootstocks raised in polybags using young budding technique
Neither any symptoms of phytotoxicity nor abnormalities in any of the morphological attributes of the rubber seedlings were observed upon Sodium nitroprusside (SNP) treatments at any growth stage irrespective of SNP concentrations
No significant effect on number of leaves due to SNP application was observed at any growth stage, i.e. at one month or at five months of the rubber seedlings (Table 1)

Summary

Introduction

The standard practice adopted in the commercial propagation of rubber (Hevea brasiliensis) clones is by grafting buds of selected clones on to unselected seedling rootstocks raised in polybags using young budding technique. To effectively carry out such critical function, distinct plant hormones intensively interact among themselves and with other endogenous signaling substances (Santner et al, 2009) Among these hormone-interacting molecules, the gaseous free radical nitric oxide (NO) has recently gained special interest in the research community given its involvement in a number of signaling cascades controlling plant responses ranging from seed germination to plant senescence (Mur et al, 2012; Freschi, 2013; Kong et al, 2014). Exogenous SNP, in a dose-dependant manner, ameliorates the root architecture and growth characteristics of rubber seedlings. To our knowledge, this is the first report on application of SNP to rubber seedlings to study the effect of NO

Methods

Results

Conclusion