Active yeast extract counteracts the harmful effects of salinity stress on the growth of leucaena plant

- Increasing salt concentration till 8000 ppm significantly decreased all investigated growth parameters, except proline.
- Yeast extract treatment recovering the reduction occurred in vegetative growth of leucaena plants which exposed to salinity stress.
- The favorable growth, chemical and anatomical characters could be obtained when using yeast extract at 100 ml/L with 4000 ppm salinity.

The current investigation was carried out at the Nursery of Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, Giza, Egypt during the two successive growing seasons of 2014 and 2015 in order to ameliorate the growth of leucaena plants grown under different levels of salinity in irrigation water (2000, 4000 and 8000 ppm) by foliar spray with active yeast extract (100 ml AYE/L.).The obtained results indicated that increasing salt concentration significantly decreased all investigated growth parameters (plant height, stem diameter, number of compound leaves developed/plant, fresh weight of stems/plant, fresh weight of leaves/plant and plant biomass). Likewise, concentration of chloroplast pigments and percentage of crude protein in leaves were decreased especially those plants grown under 4000 and 8000 ppm salinity. By contrast, increased salinity level more than 200 ppm induced significant increase in proline concentration in leucaena leaves. At the same time, the decrease in stem diameter which was observed due to salinity stress could be attributed mainly to the prominent decrease in all included tissues (periderm, cortex, phloem, xylem and pith). Data also revealed that leucaena plants grown under stress of different levels of salinity and sprayed with active yeast extract (AYE) had better growth behavior than those unsprayed. It was found that yeast extract treatment had the ability to induce significant recovery for the reduction occurred in vegetative growth of leucaena plants which exposed to salinity stress.