Postharvest temperature and water status influence postharvest splitting susceptibility in summer radish (Raphanus sativus L.).

BACKGROUND: Splitting is a problem that seriously affects appearance and marketability in a number of fruit and vegetables. In summer radish (Raphanus sativus L.), splitting can occur during growth, harvesting and postharvest. We investigated the factors affecting splitting susceptibility in summer radish cv. Celesta during postharvest handling. RESULTS: Splitting susceptibility was negatively related to temperature, with higher temperature reducing splitting due to dropping impact. Radish diameter was positively associated with compression failure force, suggesting that larger radishes are more resistant to compressive splitting. An increase in radish hypocotyl water content (WC) was associated with an increase in splitting susceptibility due to impact and decrease in failure force for both compression and puncture forces. Increased hypocotyl WC may increase splitting susceptibility by increasing the water potential of the radish tissue. In agreement, we found that increased hypocotyl WC was associated with higher internal water potential in radish tissue. CONCLUSIONS: We therefore recommend that the hypocotyl WC of summer radish crops be managed during the harvest and postharvest phases, and that crops are processed at higher, ambient, temperature in order to reduce splitting, before storing at low temperature and high humidity to maintain quality and shelf life. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Nitric oxide synthase regulates morphogenesis of zebrafish spinal cord motoneurons.

Nitric oxide (NO) is a signaling molecule that is synthesized in a range of tissues by the NO synthases (NOSs). In the immature nervous system, the neuronal isoform of NOS (NOS1) is often expressed during periods of axon outgrowth and elaboration. However, there is little direct molecular evidence to suggest that NOS1 influences these processes. Here we address the functional role of NOS1 during in vivo zebrafish locomotor circuit development. We show that NOS1 is expressed in a population of interneurons that lie close to nascent motoneurons of the spinal cord. To determine how this protein regulates spinal network assembly, we perturbed NOS1 expression in vivo with antisense morpholino oligonucleotides. This treatment dramatically increased the number of axon collaterals formed by motoneuron axons, an effect mimicked by pharmacological inhibition of the NO/cGMP signaling pathway. In contrast, exogenous elevation of NO/cGMP levels suppressed motor axon branching. These effects were not accompanied by a change in motoneuron number, suggesting that NOS1 does not regulate motoneuron differentiation. Finally we show that perturbation of NO signaling affects the ontogeny of locomotor performance. Our findings provide evidence that NOS1 is a key regulator of motor axon ontogeny in the developing vertebrate spinal cord.