hello, you should not run total RNA in agarose gel, there is always the chance that this leads to degradation,

for a economic approach, try Bleach Agarose Gel

http://www.ncbi.nlm.nih.gov/pubmed/22222980

also, nanodrop will measure quantity and purity but not integrity, you have RNA but it has degraded.

try another electrophoretic method and check for integrity.

Dear Dem

as already mentioned nanodrop measures sample purity but not RNA integrity. In the context of your plant material I surmise that phenolic compounds that require specialist removal; are not specifically detected by 260/280 or 260/230; and if contaminating your final DNA prep will degrade your genomic DNA. Removal of phenolic residues with CTAB, PVDF or boric acid will possibly prevent degradation. In particular 

• 260/280 ratios of >1.7 imply minimal contamination with proteins and especially RNAses
• 260/230 ratios > 1.0 imply minimal contamination with salts and especially GITC designed to provide a stable extraction environment by inhibiting RNAses
• Thus the usual candidates for degradation are probably not responsible
• In Contrast phenolic compounds replete in plants paradoxically increase 260/280   suggesting nothing untoward but in fact mask a contaminant that can degrade DNA and RNA
• Indeed sometimes in the context of plant materials when 260/280 ratio is > 2.0 it sometimes suggests the presence of these compounds 
• To remove these compounds perform a CTAB extraction before conventional trizol and chloroform followed by isopropanol precipitation and 70% ethanol wash which remove protein lipids and GITC respectively 
• https://www.researchgate.net/file.PostFileLoader.html?id=552711a3d3df3eda7c8b456d&assetKey=AS%3A273753966088229%401442279439964
• http://www.ncbi.nlm.nih.gov/m/pubmed/18618437/