**3. Results**

#### *3.1. First Experiment*

At harvest, broccoli raab showed twice the number of true leaves per seedling compared to other genotypes, while the average leaf length was about 1.28 cm, without any di fference between genotypes, treatments and their interaction (Table 3). In regards to yield, broccoli raab fertigated with 1/8 strength NS showed an amount 43% lower compared with cauliflower, and 40% lower compared with broccoli raab fertigated with NS 1/2 (Figure 2). Microgreens fertigated with the 1/8 strength NS showed the lowest seedling height, which was 17% lower than those fertigated with 1/4 strength NS and 25% lower than those fertigated with 1/2 strength NS (Table 3). On the other hand, broccoli raab microgreen height was 9% lower compared with broccoli (Table 3).

**Table 3.** Main e ffects of genotypes and nutrient solution strength on number and length of true leaves, yield and seedling height of microgreens (first experiment).


Significance: \*\*\*, \*\*, and \* respectively for *p* ≤ 0.001, *p* ≤ 0.01, and *p* ≤ 0.05; NS, not significant. Means values (± standard deviation) within each column and main effect followed by different letters are significantly different, according to SNK test (*p* = 0.05).

**Figure 2.** Yield of three genotypes of microgreens grown with three NS strengths: 1/2 strength, 1/4 strength and 1/8 strength (first experiment). Different letters indicate that mean values are significantly different, according to the SNK test (*p* = 0.05). Vertical bars represent ± standard deviation of mean values.

The average values of development stage and density were, respectively, 3.0 and 4.0, without differences between genotypes, nutrient solution strength and their interaction (Table 4). Cauliflower showed a substrate coverage 27% lower than the other genotypes, while broccoli raab showed a value of substrate uniformity 43% higher than cauliflower (Table 4).


**Table 4.** Main effects of genotypes and nutrient solution strength on development stage, substrate coverage, substrate uniformity and density of microgreens (first experiment).

(1) Development stage: 1—cotyledonary leaves; 2—true leaves (≤5 mm); 3—true leaves (>5mm). (2) Substrate coverage: 1—low; 2—good; 3—excessive. (3) Substrate uniformity: 1—not uniform in the centre; 2—uniform; 3—not uniform along the side. Significance: \*\*, and \* respectively for *p* ≤ 0.01, and *p* ≤ 0.05; NS, not significant. Means values (± standard deviation) within each column and main effect followed by different letters are significantly different, according to SNK test (*p* = 0.05).

#### *3.2. Second Experiment*

Even in this experiment, broccoli raab showed twice the number of true leaves compared to broccoli and cauliflower, with leaves longer than 1 cm and seedling height 7% lower compared to the other species (Table 5). Cauliflower yield was 35% higher than broccoli raab and broccoli, beyond the chemical forms of nitrogen used (Table 5).


**Table 5.** Main effects of genotypes and the NH4:NO3 ratio on the number and length of true leaves, yield and height of microgreens (second experiment).

Significance: \*\*\*, and \* respectively for *p* ≤ 0.001 and *p* ≤ 0.05; NS, not significant. Means values (± standard deviation) within each column and main effect followed by different letters are significantly different, according to SNK test (*p* = 0.05).

By using a NS with a NH4:NO3 25:75 molar ratio, microgreens showed the highest content of Cl− and K<sup>+</sup>. Cl− was 75% higher in microgreens grown with a NH4:NO3 25:75 molar ratio than other samples, while K<sup>+</sup> was 6% and 19% higher in microgreens grown with a NH4:NO3 25:75 molar ratio than NH4:NO3 15:85 and 5:95 molar ratios, respectively. Between genotypes, broccoli showed a K<sup>+</sup> content 11% higher than other genotypes (Table 6).

Microgreens grown by using a NS with a NH4:NO3 15:85 molar ratio showed a SO4<sup>2</sup>− content 13% higher than the other molar ratio (Table 6). Between the genotypes, cauliflower showed a SO4<sup>2</sup>− content of 14% and 28% higher than broccoli and broccoli raab, respectively (Table 6). Ca2+ content was 14% higher in microgreens grown with the molar ratio NH4:NO3 5:95 than 25:75, while the average Mg<sup>2</sup>+ content was 0.3 g 100 g<sup>−</sup><sup>1</sup> DW, without differences between genotypes, NH4:NO3 ratios and their interaction (Table 6).

Broccoli raab had the lowest and highest nitrate content with the molar ratio NH4:NO3 5:95 and 15:85, respectively, while broccoli showed the lowest and highest nitrate content with NH4:NO3 25:75 and 15:85, respectively. No differences were found in nitrate content in cauliflower by using different NH4:NO3 ratios (Figure 3).

Cauliflower grown using a NS with a NH4:NO3 25:75 molar ratio showed the highest sodium content, which was 31% higher than the two other molar ratios used for the same genotype (Figure 4). Broccoli raab grown by using a NS with a NH4:NO3 5:95 molar ratio showed a sodium content 36% higher than the other molar ratios of the same genotype. The average sodium content in broccoli was 0.15 g 100−<sup>1</sup> DW, without differences between NH4:NO3 molar ratios (Figure 4).



Significance: \*\*\*, \*\*, and \* respectively for *p* ≤ 0.001, *p* ≤ 0.01, and *p* ≤ 0.05; NS, not significant. Means values (± standard deviation) within each column and main effect followed by different letters are significantly different, according to SNK test (*p* = 0.05).

**Figure 3.** Nitrates (NO3−) content of three genotypes of microgreens grown by using a NS with three different NH4<sup>+</sup>:NO3− (%) molar ratios: 5:95, 15:85 and 25:75. Different letters indicate that mean values are significantly different, according to the SNK test (*p* = 0.05). Vertical bars represent ± standard deviation of mean values.

**Figure 4.** Sodium (Na+) content of three genotypes of microgreens grown by using a NS with three different NH4<sup>+</sup>:NO3− (%) molar ratio: 5:95, 15:85 and 25:75. Different letters indicate that mean values are significantly different, according to the SNK test (*p* = 0.05). Vertical bars represent ± standard deviation of mean values.

The highest value of dry matter was obtained from cauliflower grown with a NH4:NO3 25:75 molar ratio that resulted in 66% higher content than the two other molar ratios of the same genotype (Figure 4). Broccoli showed a dry matter content 31% lower with a NH4:NO3 25:75 molar ratio compared to other molar ratios. The average content of dry matter in broccoli raab was 6.3 g 100−<sup>1</sup> FW, without differences between NH4:NO3 molar ratios (Figure 5).

**Figure 5.** Dry matter content of three genotypes of microgreens grown by using a NS with three different NH4<sup>+</sup>:NO3− (%) molar ratios: 5:95, 15:85 and 25:75. Different letters indicate that mean values are significantly different, according to the SNK test (*p* = 0.05). Vertical bars represent ± standard deviation of mean values.

The average fiber content was 0.518 g 100 g<sup>−</sup><sup>1</sup> FW without significant differences between genotypes, NH4:NO3 molar ratios and their interaction (Table 7). Cauliflower showed an α-tocopherol content 194% higher than other genotypes, while broccoli raab showed a β-carotene content about 40% lower than other genotypes. The highest value of β-carotene was obtained with a NH4:NO3 25:75 molar ratio that resulted in 40% higher content than the two other molar ratios (Table 7).


**Table 7.** Effects of genotypes and NH4:NO3 ratio on fiber, protein, α-tocopherol and β-carotene content (second experiment).

Significance: \*\*, and \* respectively for *p* ≤ 0.01, and *p* ≤ 0.05; NS, not significant. Means values (± standard deviation) within each column and main effect followed by different letters are significantly different, according to SNK test (*p* = 0.05).

As for protein content, cauliflower grown with a NH4:NO3 25:75 molar ratio gave the highest value, which resulted in 79% higher content than the other nutrient solutions (Figure 6).

**Figure 6.** Protein content of three genotypes of microgreens grown by using a NS with three different NH4<sup>+</sup>:NO3− (%) molar ratios: 5:95, 15:85 and 25:75. Different letters indicate that mean values are significantly different, according to the SNK test (*p* = 0.05). Vertical bars represent ± standard deviation of mean values.
