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Trochophore and veliger are vulnerable pelagic larvae and susceptible to environmental toxicants, which are extremely crucial for the population renewal. Cu, Zn and Cd pollution are common elements in metal pollution in coastal areas. Though Pacific abalone is the main economic mollusc in China, its larval response to metals remains unclear. To understand this, the effect of Cu, Zn and Cd toxicity on malformation classification and respiratory metabolism of trochophore and veliger are analysed and measured in this paper. The 48 hr EC50 for abalone trochophore was (18.9 ± 1.0) μg/L for Cu, (65.1 ± 0.3) μg/L for Zn and (1,377.8 ± 68.9) μg/L for Cd respectively. The LC50 of veliger was (45.8 ± 0.9) μg/L for Cu, (50.0 ± 0.9) μg/L for Zn and (1,049.3 ± 37.6) μg/L for Cd respectively. Trochophore died with no shell at 128 μg/L Cu, yet remained alive with multiple broken‐shell bodies at 128 μg/L Zn and failed to form well‐developed shells at 20,480 μg/L Cd. All veliger died with complete shells at the mentioned concentrations. A self‐made device was used to study the effect on respiratory metabolism. The respiratory metabolism level was significantly fluctuating under Cu and Zn exposure and declined under Cd. The results indicated a decreasing order of the metal toxicity to trochophore and veliger as follows: Cu > Zn ≫ Cd. Cu and Zn were the main causes of shell abnormality, and Cd was less toxic. Moreover, the affected respiratory has a negative impact on further larval development. [ABSTRACT FROM AUTHOR]

• Dongbi longan had a lower aril breakdown index and respiration rate than Fuyan longan. • Dongbi longan had lower aril PGI, SDH, CCO, AAO, PPO activities and NAD(H) content. • Dongbi longan had higher aril NADK and G-6-PDH+6-PGDH activities and NADP(H) content. • Lower aril breakdown of Dongbi via reducing EMP, TCA, CCP and raising PPP respiratory. • Higher aril breakdown of Fuyan by raising EMP, TCA, CCP, and reducing PPP respiratory. This study aimed to investigate the difference between 'Fuyan' longan (Dimocarpus longan Lour. cv. Fuyan) fruit and 'Dongbi' longan (Dimocarpus longan Lour. cv. Dongbi) fruit in term of their aril breakdown and respiratory metabolism. As compared to 'Fuyan' longans, the 'Dongbi' longans exhibited lower fruit respiration rate, lower aril breakdown index, higher NADK activity, higher total activities of G-6-PDH and 6-PGDH, higher contents of NADP and NADPH, lower activities of AAO, CCO, PPO, PGI, and SDH, and lower contents of NAD and NADH in aril. These findings suggest that better storability and lower aril breakdown index in 'Dongbi' longans than 'Fuyan' longans might be due to lower activities of respiratory terminal oxidases, and lower respiratory metabolic pathways of EMP-TCA cycle related-enzymes in 'Dongbi' longan aril, which decreased respiratory rate and reduced the consumption of substrates, and subsequently maintained the integrity of the aril of 'Dongbi' longans during storage. [ABSTRACT FROM AUTHOR]

• SA retarded the disease development of harvested longans caused by P. longanae. • SA raised longan disease resistance via regulating energy and respiratory metabolism. • SA maintained a higher level of energy charge in P. longanae- inoculated longans. • SA reduced respiration rate but raised PPP pathway in P. longanae -inoculated longans. • SA raised EMP, TCA cycle and CCP pathways in P. longanae -inoculated longans. This study investigated the effects of salicylic acid (SA) on the disease development, respiration rate, energy status, and respiratory metabolism in Phomopsis longanae Chi-inoculated longans. SA treatment reduced the fruit disease index and respiration rate of P. longanae -inoculated longans as compared to the fruit with mere inoculation. SA treatment suppressed the decline of energy charge, decreased the activities of PGI, SDH and CCO, but boosted the G-6-PDH+6-PGDH and NADK activities. Meanwhile, the NAD and NADH contents were decreased, but NADP and NADPH contents were increased. These findings demonstrated that SA could be used to the inhibit disease development in harvested longans because SA treatment helped maintain a high energy charge level, decreased respiration rate and respiratory pathways like EMP-TCA cycle and CCP, but increased PPP respiratory pathway. This study indicated that the SA treatment was a facile and effective way to retard the disease development of postharvest longans. [ABSTRACT FROM AUTHOR]