# Soybean Germination Response to Algae Extract and a Static Magnetic Field Treatment
## 2 Materials and Methods
### Germination Tests  
The germination test of soybean seeds was assessed according to the International Seed Testing Association (ISTA) methodology. A paper substrate was used to perform the germination experiment, which was carried out in 4 replications. One replication consisted of 100 soybean seeds. The temperature in the growth chamber was 25 \({}^{\circ}\)C. The germination tests were conducted in two stages. In the first stage, different concentrations of extracts, 20%, 40%, 60%, 80%, and 100%, were applied to a paper substrate to select the best one. Independent of concentration, 240 mL of algal extract per replication was added directly to the paper substrate before soybean seeds were sown. The highest number of normal seedlings was observed at 20% and 80% extract, which was used in further experiments (simultaneous seed stimulation with extract and SMF). At the same time, seeds were exposed to the second factor-static magnetic field. The exposure times were 3 and 12 min and the magnetic inductions were 250 and 500 mT. The best developed seedlings were found after treatment for 3 min and a magnetic induction of 250 mT. In the second step, the simultaneous effects of the best (20% and 80%) algal extracts and seed treatmentswith 3 min at 250 mT SMF were tested. The experimental groups tested in this study are presented in Figure 1.  
The counting of soybeans was conducted after 8 days. The seedlings were stored in a growth chamber at a constant temperature of 25 \({}^{\circ}\)C. After 8 days, seedlings were carefully extracted from the paper substrate and then divided into normal and abnormal groups, according to ISTA demands. The example of normal and abnormal seedlings is presented in Figure 2. The germination ability was assessed and is given in percentages. The minimum germination requirement was 80% (according to the regulation of The Ministry of Agriculture and Rural Development from 27 May 2020, according to Polish Official Journal from 2 June 2020, item 975). Soybean germination is referred to as epigeal because cotyledons are pulled above the soil surface. Usually, the differences between well-developed and abnormal seedlings are connected with dwarfism, rotten due to primary infection, lack of chlorophyll (albinotic seedling), an irregular hypocotyl shape or its different defects. It should be emphasized that abnormal seedlings simply do not show the ability to develop into a normal, healthy plant (growing in soil under favorable conditions). From all replications, 30 normal seedlings were chosen to measure their root, hypocotyl and epicotyl length, and dried biomass weight.  
The germination percentage was calculated as number of normal seedlings out of all seedlings. Normal seedlings all have essential structures--the primary root is intact or shows acceptable defects (discolored or necrotic spots, healed cracks and splits, superficial cracks and splits). In addition, a seedling with a defective primary root is classed as normal,  
Figure 1: General scheme of performed experiments.  
Figure 2: Soybean seedlings: normal (3 on the left) and abnormal.  
if sufficient normal secondary roots have developed. Additionally, the hypococotyl and epicotyl are intact or show acceptable defects: loose twists, superficial cracks and splits, healed cracks and splits. The cotyledons are intact or show acceptable defects--up to 50% of tissue not functioning normally, only one (intact) cotyledons, three cotyledons. Primary leaves are intact or show acceptable defects--only one (intact) primary leaf, three primary leaves, and normal shape but retarded growth. The seedling is abnormal if it is deformed, is fractured, has cotyledons emerging before the primary root, consists of fused twin seedlings, is yellow or white, is spindly or glassy, or is decayed as a result of primary infection.