1. Sustainable plant based resins and fibers for seed coating
*Masoume Amirkhani1, Anil N. Netravali2, Catharine M. Catranis1, and Alan G. Taylor1
Cornell University, Department of Horticulture, Geneva, New York
Cornell University, Department of Fiber Science and Apparel Design, Ithaca, New York
INTRODUCTION
Seed enhancements may be defined as post-harvest treatments that improve germination or seedling growth, or facilitate the delivery of seeds and other materials required at the time of sowing (1); it comprises three general areas of enhancements: priming, coating and seed conditioning. Coating includes three techniques routinely used for vegetable crop seeds: film coating, encrusting and pelleting. Most coating formulations are inert and have little effect on seedling growth (2).
OBJECTIVES
QUALITY OF SEED COATINGS
PLANT GROWTH
While uncoated seed had a greater germination rate (Fig. 4) and germination maximum percent (Gmax%) than the coated seed (Tab. 2), all coating formulations showed a statistically significant increase in seedling growth (seed vigor index, SVI) (Tab. 2 & Fig. 5).
In general, formulations having a higher percentage of soy flour have greater mechanical integrity (Fig. 3 and Tab. 1).
The goal of this project is to develop coating formulations with desired properties including growth enhancement using a renewable resource for the coating filler and binder.
Table 2. Seedling growth, Gmax and Seed Vigor Index (SVI=Gmax% x seedling length).
The specific objectives of the project are:
Develop a seed coating using soy flour (SF) as the binder.
Determine the effect of binder content on coating integrity.
Determine the effect of filler ingredient content on germination and early seedling growth.
(a)
(b)
(c)
Treatment
Formula (SCD)
Gmax%
Seedling Length (cm)
SVI
Control1
Uncoated
92A
10.4c
9.59C
Control2 *
89A
14.1A
12.55A SD *
86B
14.4A
12.38A
78D
12.8B
9.98BC
13.3A
10.37B
85B
13.8A
11.73A
SCD
81C
13.5A
10.94AB
83BC
13.6A
11.29A
79C
14.3A
11.30A
80C
12.9B
10.32B
Figure 2. Broccoli seeds: (a) non-treated; (b) coated with biodegradable coating formulation Soy Flour: Cellulose: Diatomaceous Earth (SCD), 40:20:40; and (c) SD 50:00:50 using the R6.
Table 1. Time for coating to disintegrate in water (mins).
Treatments (SCD)
Time to start of disintegrating (mins) 35 60 90
120
180
105
150
METHODS & MATERIALS
* Lower mechanical integrity of coat compared to SD & SCD treatments.
The coating was applied with rotary pan (R6) technology (Fig. 1) with 35% build-up (Fig. 2).
The soy flour-based binder was applied as a 10% water-based solution with a basic pH (pH 10).
Broccoli seeds were coated using soy flour-based binder and a combination filler consisting of diatomaceous earth, soy flour, and cellulose.
•The coating strength was examined by two methods: percent coating loss after vibration using a Ro-Tap (Mechanical Integrity, Fig. 3) and time for the coating to disintegrate in water (Tab. 1).
The percent germination was recorded daily and germination rate was calculated.
Root and shoot growth were recorded after 1 week.
CONCLUSIONS
Coating ingredients can act as a biostimulants. Biostimulants are mixtures of one or more components (e.g., microorganisms, trace elements, enzymes, plant hormones, and seaweed extracts) that may enhance nutrient availability, water-holding capacities, increase antioxidants, enhance metabolism and increase chlorophyll production.
Enhanced seedling growth in all formulations was attributed to the protein from both filler and binder.
Figure 3. Weight loss% (Mechanical Integrity)
GERMINATION CHARACTERISTICS
Figure 4. Comparison of cumulative germination percentage by treatment type (SCD) using the roll towel test for coated and uncoated broccoli seeds.
ACKNOLEDGEMENTS
This project (NYC ) )was supported by Hatch funds to Drs A. N. Netravali and A. G. Taylor.
REFRENCES
Figure 5. Comparison of average seedling length for coated and uncoated broccoli seeds; (a) uncoated at 10.4cm and (b) 40:20:40 at 14.3 cm.
Taylor, A. G Seed treatments. In: Thomas, B, D. J. Murphy and B. G. Murray. Encyclopedia of Applied Plant Sciences. Elsevier Acad. Press. p
Taylor, A. G., P. S. Allen, M. A. Bennett, K. J. Bradford, J. S. Burris and M. K. Misra Seed enhancements. Seed Science Research 8:  
3. US patent application number: 12/777,804
Figure 1. Seed coating using the rotary pan (R6).
New York State Seed Testing Laboratory
(a)
(b)