Effects of corn steep liquor (organic fertilizer, OF) and conventional chemical fertilizer (CF) on the growth and yield of bok choy (Brassica rapa var. chinensis) in summer and autumn hydroponic growing systems were compared. When OF and CF were applied with the same amount of total nitrogen in summer cultivation, there was no significant difference between yields; however, the growth rate in OF was slower than in CF. When OF was applied with twice the amount of nitrogen in CF (OF2), bok choy growth and yield were significantly inhibited in summer cultivation, likely owing to dissolved oxygen deficiency and different rates of nitrification and nitrogen absorbance by the plant root. Although the contents of potassium, calcium, and magnesium in bok choy showed no difference among the three treatments in both cultivation seasons, the carbon/nitrogen ratio tended to be higher in OF and OF2 than in CF. Lower nitric acid and higher ascorbic acid content was found in OF and OF2 than in CF. Overall, our results suggest that a comparable yield is expected by using the same nitrogen amount with a conventional recipe of chemical fertilization in autumn cultivation. However, further improvement of hydroponic management is needed in summer cultivation.

Here, we propose that organic hydroponics trigger induced systemic resistance (ISR) in lettuce against air-borne Botrytis cinerea, which causes gray mold. We compared effects of organic and chemical hydroponics, assessed presence of ISR elicitors in the hydroponic nutrient solution, and investigated molecular mechanism of ISR. Organic hydroponics significantly reduced gray mold lesions in lettuce (cultivated hydroponically) and cucumber (cultivated in soil and foliar sprayed with nutrient solution). The 1-aminocyclopropane-1-carboxylic acid synthase gene in lettuce and lipoxygenase and ethylene receptor-related gene in cucumber showed heightened expression, suggesting that the jasmonic acid/ethylene (JA/ET)-signaling pathway was involved in ISR for both crops. Low salicylic acid β-glucoside levels confirmed role of the ISR signaling pathway. ISR in both lettuce and cucumbers indicated that elicitors in organic hydroponics were nonhost-specific and that the JA/ET pathway was activated without microbe–root interaction. Thus, organic hydroponics can be an effective method for both soil-borne and air-borne disease control.

We investigated the role of heat shock transcription factors (Hsfs) during induction of defense response by heat-shock treatment (HST) in tomato. Leaf disease symptoms were significantly reduced at 12 and 24 h after HST, consistent with upregulation of pathogenesis-related (PR) genes PR1a2 and PR1b1 peaking at 24 h after treatment. These genes were upregulated at the treatment application site, but not in untreated leaves. In contrast to HST, inoculation of the first leaf induced systemic upregulation of acidic PR genes in uninoculated second leaves. Furthermore, heat shock element motifs were found in upstream regions of PR1a2, PR1b1, Chitinase 3, Chitinase 9, Glucanase A, and Glucanase B genes. Upregulation of HsfA2 and HsfB1 peaked at 6 h after HST, 6 h earlier than salicylic acid accumulation. Foliar spray of heat shock protein 90 (Hsp90) inhibitor geldanamycin (GDA) induced PR gene expression comparable to that after HST. PR gene expression and defense response against Pseudomonas syringae pv. tomato (Pst) decreased when combining HST with Hsfs inhibitor KRIBB11. The Hsfs and PR gene expression induced by heat or GDA, together with the suppression of heat shock-induced resistance (HSIR) against Pst by KRIBB11, suggested a direct contribution of Hsfs to HSIR regulation in tomato.

To pursue the mechanism of retrograde ejaculation after bilateral hypogastric nerve transections, the disability of the lumbosacral sympathetic trunk and the spermatic nerve to compensate bladder neck closure was investigated while both act as compensatory pathways for seminal emission. Five mongrel dogs were used for each experiment. By manual penis-stimulation, all dogs showed only retrograde ejaculation one month and six months after transection of bilateral hypogastric nerves. Bladder neck closure did not occur by electrical stimulation of either the lumbosacral sympathetic trunk or the spermatic nerve before and one month after transection of bilateral hypogastric nerves in all dogs examined and persistent relaxation of bladder neck was observed one and six months after transection of bilateral hypogastric nerves. The present results and our previous data indicate that retrograde ejaculation after bilateral hypogastric nerve transections is attributable to the absence of effective compensatory sympathetic pathways for bladder neck closure under the recovery of seminal emission by compensatory pathways.