The growth-enhancing property of DCPTA was tested on transplanted seedlings of Brassolaeliocattleya × Hort. (Blc. Bryce Canyon × Lc. Pirate King), Dendrobium × Blume. Hickham Deb, Epidendrum radicans Pav. ex Lindl., Lueliocattleya × Rolfe Prism Palette `The Clown', and Phalaenopsis × Blume. [Pink Zebra × (Jutta Brungor × Music)]. After 3 to 6 months of greenhouse growth, plants treated with 30 μm DCPTA produced a 2- to 3-fold increase in root growth compared to the controls. Shoot growth, root: shoot ratio, and the survival of DCPTA-treated plants were increased significantly when compared with controls. Chemical name used: 2-(3,4-dichlorophenoxy)triethylamine (DCPTA).
James H. Keithly, Daniel P. Jones, and Henry Yokoyama
Masoume Amirkhani, Anil N. Netravali, Wencheng Huang, and Alan G. Taylor
This research presents a novel method of using plant-derived protein hydrolysates as seed coating materials. The objective of this study was to develop seed coating formulations using soy flour, a sustainable, inexpensive, and green source, as a biostimulant using broccoli as the model system. A 10% suspension of soy flour was used as the seed treatment binder in all coatings. The solid particulate filler was composed of mixtures of soy flour, cellulose, and diatomaceous earth, together termed as SCD. All SCD components were homogenized in water, then dried and ground to a fine particle size <106 µm. The SCD coatings were applied with rotary pan seed coating equipment at 25% of the seed weight. Increasing the proportion of soy flour increased the seed coating strength and also the time for the coating to disintegrate after soaking in water. As a result, the seed coatings reduced the percentage germination and the germination rate compared with the nontreated control. However, the 10-day-old seedling root and shoot growth showed significant improvement for all SCD coating treatments compared with controls. Plant growth and development was also measured after 30 days in the greenhouse. Fresh weight (FW) and dry weight (DW), leaf area, plant height, leaf development, Soil-Plant Analyses Development (SPAD) index (chlorophyll measurement), and nitrogen (N) per plant were all greater from coatings with 30%, 40%, and 50% soy flour than the noncoated control. Nitrogen, from the soy flour applied in the seed coatings, ranged from 0.024 to 0.073 mg per seed, while the enhanced N per plant ranged from 1.7 to 8.5 mg. The coating treatment with 0.063 mg N per seed resulted in the greatest plant leaf area and highest N content. Nitrogen applied in the seed coating only accounted for 1% to 2% of the enhanced N in the plants, indicating the soy flour acted as a biostimulant rather than a fertilizer.
Victoria Estaún, Amelia Camprubí, Cinta Calvet, and Jorge Pinochet
This paper reports the effects of inoculation with arbuscular mycorrhizal fungi on early plant development, field establishment, and crop yield of the olive (Olea europaea L.) cultivar Arbequina. The response of olive plants to the fungi Glomus intraradices (Schenck and Smith) and G. mosseae (Nicol.& Gerd.) Gerdemann & Trappe in different potting mixes was studied in two different nursery experiments. Pre-inoculation with selected arbuscular mycorrhizal fungi prior to transplanting in the field improved plant growth and crop yield up to three years after inoculation. G. intraradices was more efficient at promoting plant growth than both G. mosseae and the native endophytes present in the orchard soil. Inoculation at the time of transplanting enhanced early plant growth in all the field situations studied. Diminishing mycorrhizal effects over time resulted from natural colonization of noninoculated seedlings and related to the native arbuscular mycorrhizal (AM) fungal population of the field soil. Early inoculation of olive seedlings enhances early plant development and crop productivity of olive trees.