Growth Responses of Bermudagrass to Various Bio-Stimulants Under Salinity Stress.

Growth responses of bermudagrass (Cynodon dactylon L.), cv. Tifway to three Bio-stimulants (Bio-Turf-Pro, Encapsalt, and Ferrogrow) were studied hydroponically under EC of 15 dSm^-1 sodium chloride (NaCl) stress in a greenhouse. In this experiment, a randomized complete block (CRB) design was used with 4 replications of each treatment. The growth responses of the grasses included shoot and root lengths, both shoot and root fresh and dry weights, and the grasses’ general quality. The grasses were grown vegetatively in half-strength Hoagland solution for 12 weeks for complete establishment. During this period, the shoots were clipped weekly to have uniform grasses in all the experimental units (cups), and the clippings were discarded. At the week 12, the roots were also cut and discarded to have all the grasses with similar roots. Then, the salt stress was imposed and the Bio-stimulants were applied. The grasses were allowed to grow for 7 weeks at this phase of the experiment. During this period (7 weeks), the shoots and roots’ lengths were measured and the grasses’ general qualities were evaluated weekly. Then, the shoots were harvested, and the clippings fresh and dry weights (oven-dried at 65 ^oC) were measured and recorded. At the last harvest (the 7^th week harvest), roots were also harvested and their fresh and dry weights determined. The results showed, all the Bio-stimulants slightly enhanced the shoot and the root heights at each weekly measurement, but, the enhancement in shoot heights was not statistically significant. Shoot weights, especially the fresh weights, of all the grasses were significantly higher under Bio-stimulant treatments compared with the control plants. Although the root weights of the grasses were stimulated by all the Bio-stimulants, the differences between the root weights of the Bio-stimulants treated grasses and the controls were not statistically significant. Among the three Bio-stimulants, Encapsalt showed numerically the lowest enhancement on shoot and root heights, but the highest enhancement in shoot and root weights and grass density. This is important, because lower shoot height and higher grass density are desirable quality factors in turfgrass management. Under salinity stress, the grasses’ general quality was substantially improved by all the Bio-stimulants compared with the controls (No Bio-stimulant, but containing NaCl).