Genetic diversity of black mangrove (Rhizophora mucronata Lamk.) based on morphological markers in Maros, Pangkep, and Barru Provenances

Mangrove forests are tropical and subtropical forests that grow typically along the coast or river estuaries. Black mangroves are a type of mangrove found in South Sulawesi, precisely in Maros, Pangkep, and Barru Districts. The decline in black mangrove populations overcomes the threat limit to germplasm which can lead to reduced genetic diversity in black mangrove plants. To reduce the incidence of extinction in black mangroves, information on genetic diversity using one of the markers is required, namely morphological markers in taking samples of tree parts taken, namely the leaves, stems, and roots which are then for monitoring carried out in the Biotechnology Laboratory and tree breeding. The method used in this study is based on the literature on the development of the Tropical Fruit Descriptor information system. The results of the three studies proved that there is a difference between the evidence and the interprovenencies. The very close morphological kinship between them proved to be found in Pangkep. Pangkep’s provenance has a high coefficient compared to the proof of Maros and Barru, which is at the time level of 70%, while the proof of Maros has the lowest coefficient compared to the proof of Barru and Pangkep, which is at the gathering level of 64%.

Salinity has little effect on photosynthetic and respiratory responses to seasonal temperature changes in black mangrove (Avicennia germinans) seedlings

Temperature and salinity are important regulators of mangrove range limits and productivity, but the physiological responses of mangroves to the interactive effects of temperature and salinity remain uncertain. We tested the hypothesis that salinity alters photosynthetic responses to seasonal changes in temperature and vapor pressure deficit (D), as well as thermal acclimation _of leaf respiration in black mangrove (Avicennia germinans). To test this hypothesis, we grew seedlings of A. germinans in an outdoor experiment for ~ 12 months under four treatments spanning 0 to 55 ppt porewater salinity. We repeatedly measured seedling growth and in situ rates of leaf net photosynthesis (Asat) and stomatal conductance to water vapor (gs) at prevailing leaf temperatures, along with estimated rates of Rubisco carboxylation (Vcmax) and electron transport for RuBP regeneration (Jmax), and measured rates of leaf respiration at 25 °C (Rarea25). We developed empirical models describing the seasonal response of leaf gas exchange and photosynthetic capacity to leaf temperature and D, and the response of Rarea25 to changes in mean daily air temperature. We tested the effect of salinity on model parameters. Over time, salinity had weak or inconsistent effects on Asat, gs and Rarea25. Salinity also had little effect on the biochemical parameters of photosynthesis (Vcmax, Jmax) and individual measurements of Asat, gs, Vcmax and Jmax showed a similar response to seasonal changes in temperature and D across all salinity treatments. Individual measurements of Rarea25 showed a similar inverse relationship with mean daily air temperature across all salinity treatments. We conclude that photosynthetic responses to seasonal changes in temperature and D, as well as seasonal temperature acclimation of leaf R, are largely consistent across a range of salinities in A. germinans. These results might simplify predictions of photosynthetic and respiratory responses to temperature in young mangroves.

Draft Genome Sequence of a Novel Species of Halococcus (Strain IIIV-5B), an Endophytic Archaeon Isolated from the Leaf Tissue of Avicennia germinans

ABSTRACT Strain IIIV-5B was isolated from the leaf tissue of the black mangrove, Avicennia germinans. This microorganism belongs to the genus Halococcus. Here, we present the draft genome sequence of strain IIIV-5B, a novel species of this genus. The 3,869,808-bp genome has a G+C content of 63.9% and around 3,812 coding sequences.