NaCl priming alleviates the inhibiting effect of salinity during seedling growth of peas (Pisum Sativum L.)

Abstract

This study was conducted to determine the availability of NaCl priming for increasing salt tolerance at different viability levels and to evaluate the effects of NaCl priming on emergence and seedling establishment of peas (Pisum sativum L.) grown under long term salinity conditions. Seeds of pea `cv. Bolero' were divided into two parts. The first part of the seed was reserved as the original (i.e., the high viability seed lot). The low viability seed lot was obtained by ageing the seeds for 5 days at 60 degrees C. Then, the seeds were primed with 150 mM NaC1 for 2 days at 16 degrees C. After priming, seeds were dehydrated for 50 hours at 20 degrees C until the original seed moisture content was reached. Non-primed and primed seeds were sown in plastic trays. The trays were irrigated with 5 different saline solutions (0.3, 2.0, 4.0, 6.0 and 8.0 dSm(-1)). Increasing salinity levels negatively affected growth of the seedlings derived from both high and low viability seeds. However, in each viability and salinity level, NaCl priming diminished the inhibiting effect of salinity on growth of pea seedlings. Total emergence, germination index, seedling vigour index, chlorophyll content, leaf relative water content, seedling length and dry weight of plants derived from primed seeds tended to be higher than those of the non-primed ones. Primed seeds emerged faster and therefore decreased mean emergence time. Then all the parameters were correlated with total emergence to determine a useful indicator for peas. The highest correlation was obtained between total emergence and emergence index.