Effect of some Natural Treatments on Vegetative Growth and Leaf Chemical Composition of Squash Plants Growing Under Cold Conditions.

Abstract

Growth of squash plants cv. Eskandarani during winter seasons of 2016 and 2017 under outdoor conditions was significantly enhanced by application of some natural treatments, i.e. seed cold hardening (SCH) at-1̊ C for 12 & 24 hours of exposure period as seed pre-sowing treatments, and salicylic acid (SA) at 100 & 200 ppm, the mineral nutrients (Ca at 250 & 500 ppm and Zn at 50 and 100 ppm and the natural extracts (GCE at 50 &100 g/l and LRE at 5 & 10 g/l) as seed soaking then foliar spray treatments. Since, significant increases in stem length and diameter, leaves number and total area / plant, as well as fresh and dry weights of roots, stems and leaves were obtained with all applied treatments. Meanwhile, significant reduction in the assimilation rate was existed. Besides, different applied treatments obviously increased photosynthetic pigments, NPK, sugars, total carbohydrates and crude protein contents in leaves of the treated plants compared with those of untreated ones. Increases were in parallel to the applied level of SCH, GCE, LRE, SA, Ca and Zn. In addition, GCE at 100 g/l was the most pronounced treatment in this respect, followed by SA at 200 ppm, LRE at 10 g/l, Ca at 500 ppm, Zn at 100 ppm and SCH at-1 for 24 hours of exposure period in descending order. Therefore, the present study strongly admit the use of natural garlic and licorice extracts, salicylic acid and some mineral nutrients as seed pre-sowing treatments not only to improve growth and productivity of squash plants during winter months under outdoors conditions but also to avoid all cautions (regarding both environment and human consumption) for inserting greenhouses production in the agricultural system.