Hybrid Pennisetum (Pennisetum americanum×P. purpureum) is a popular bioenergy grass that could also serve as forage for livestock production. In a pot experiment, salinity inhibited hybrid Pennisetum growth, photosynthesis, soluble sugar content, and NR activity; decreased K+content; and increased Na+content. These adverse effects of soil salinity were reduced, however, by applications of NO3--N up to 5 mmol·L-1; higher applications of NO3--N increased soil salinity problems. These findings will be useful for the production of hybrid Pennisetum as a biofuel on saline land.

As an essential macroelement for all living cells, phosphorus plays a significant role in agricultural production systems. To better guide the establishment of the biofuel production systems of hybrid pennisetum, a popular energy plant with important potential in saline land, the effects of nutrient phosphorus on the growth, photosynthesis and ion homeostasis of hybrid pennisetum under salt treatment were examined with greenhouse pot experiments. Plant seedlings subjected to phosphorus deficiency (0.1 mmol·L-1P and 0.2 mmol·L-1P) increased in ratio of root to shoot and decreased in biomass. On the other hand, salinity inhibited the growth of hybrid pennisetum, but the effects of salinity on energy plants (Pennisetum americanum×P. Purpureum) were influenced by the concentration of nutrient phosphorus. Salinity was more injurious to hybrid pennisetum seedlings in combination with a lower concentration of phosphorus (0.1 mmol·L-1P, 0.2 mmol·L-1P and 0.6 mmol·L-1P) than it was with a higher concentration of phosphorus (1.0 mmol·L-1P) (that gave optimum yields in the absence of salinity). In addition, no significant differences were observed between 1.0 mmol·L-1P and 1.4 mmol·L-1P levels at either NaCl level, indicating that 1.0 mmol·L-1P was enough for the enhancement of both growth and tolerance to NaCl in hybrid pennisetum.