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Fulltext Two new species of Ardisia subgenus Tetrardisia (Primulaceae-Myrsinoideae) from Borneo

Julius A, Kajita T, Utteridge TMA

PhytoKeys, 2020;145:139-148.
PMID: 32327930 DOI: 10.3897/phytokeys.145.48573

Ardisia argentiana and A. nagaensis from subgenus Tetrardisia are herein described and illustrated as new species. They are endemic to Borneo and the Indonesian province of Central Kalimantan and to the Malaysian state of Sarawak, respectively. Ardisia argentiana is unique in its linear-oblong leaves, with a long, acuminate-caudate apex, and finely serrulate margins, while A. nagaensis can be easily recognized by its elliptic-lanceolate leaves.
Correlations between allocation to foliar phosphorus fractions and maintenance of photosynthetic integrity in six mangrove populations as affected by chilling

Yan L, Sunoj VSJ, Short AW, Lambers H, Elsheery NI, Kajita T, et al.

New Phytol, 2021 12;232(6):2267-2282.
PMID: 34610157 DOI: 10.1111/nph.17770

Chilling restrains the distribution of mangroves. We tested whether foliar phosphorus (P) fractions and gene expression are associated with cold tolerance in mangrove species. We exposed seedlings of six mangrove populations from different latitudes to favorable, chilling and recovery treatments, and measured their foliar P concentrations and fractions, photochemistry, nighttime respiration, and gene expression. A Kandelia obovata (KO; 26.45°N) population completely and a Bruguiera gymnorhiza (Guangxi) (BGG; 21.50°N) population partially (30%) survived chilling. Avicennia marina (24.29°N), and other B. gymnorhiza (26.66°N, 24.40°N, and 19.62°N) populations died after chilling. Photosystems of KO and photosystem I of BGG were least injured. During chilling, leaf P fractions, except nucleic acid P in three populations, declined and photoinhibition and nighttime respiration increased in all populations, with the greatest impact in B. gymnorhiza. Leaf nucleic acid P was positively correlated with photochemical efficiency during recovery and nighttime respiration across populations for each treatment. Relatively high concentrations of nucleic acid P and metabolite P were associated with stronger chilling tolerance in KO. Bruguiera gymnorhiza exhibited relatively low concentrations of organic P in favorable and chilling conditions, but its partially survived population showed stronger compensation in nucleic acid P and Pi concentrations and gene expression during recovery.
Fulltext Development and characterization of 27 microsatellite markers for the mangrove fern, Acrostichum aureum (Pteridaceae)

Yamamoto T, Tsuda Y, Mori GM, Cruz MV, Shinmura Y, Wee AK, et al.

Appl Plant Sci, 2016 Sep;4(9).
PMID: 27672519 DOI: 10.3732/apps.1600042

PREMISE OF THE STUDY: Twenty-seven nuclear microsatellite markers were developed for the mangrove fern, Acrostichum aureum (Pteridaceae), to investigate the genetic structure and demographic history of the only pantropical mangrove plant.
METHODS AND RESULTS: Fifty-six A. aureum individuals from three populations were sampled and genotyped to characterize the 27 loci. The number of alleles and expected heterozygosity ranged from one to 15 and 0.000 to 0.893, respectively. Across the 26 polymorphic loci, the Malaysian population showed much higher levels of polymorphism compared to the other two populations in Guam and Brazil. Cross-amplification tests in the other two species from the genus determined that seven and six loci were amplifiable in A. danaeifolium and A. speciosum, respectively.
CONCLUSIONS: The 26 polymorphic microsatellite markers will be useful for future studies investigating the genetic structure and demographic history of of A. aureum, which has the widest distributional range of all mangrove plants.
Fulltext Genetic differentiation and phylogeography of partially sympatric species complex Rhizophora mucronata Lam. and R. stylosa Griff. using SSR markers

Wee AK, Takayama K, Chua JL, Asakawa T, Meenakshisundaram SH, Onrizal, et al.

BMC Evol. Biol., 2015 Mar 29;15:57.
PMID: 25888261 DOI: 10.1186/s12862-015-0331-3

BACKGROUND: Mangrove forests are ecologically important but globally threatened intertidal plant communities. Effective mangrove conservation requires the determination of species identity, management units, and genetic structure. Here, we investigate the genetic distinctiveness and genetic structure of an iconic but yet taxonomically confusing species complex Rhizophora mucronata and R. stylosa across their distributional range, by employing a suite of 20 informative nuclear SSR markers.
RESULTS: Our results demonstrated the general genetic distinctiveness of R. mucronata and R. stylosa, and potential hybridization or introgression between them. We investigated the population genetics of each species without the putative hybrids, and found strong genetic structure between oceanic regions in both R. mucronata and R. stylosa. In R. mucronata, a strong divergence was detected between populations from the Indian Ocean region (Indian Ocean and Andaman Sea) and the Pacific Ocean region (Malacca Strait, South China Sea and Northwest Pacific Ocean). In R. stylosa, the genetic break was located more eastward, between populations from South and East China Sea and populations from the Southwest Pacific Ocean. The location of these genetic breaks coincided with the boundaries of oceanic currents, thus suggesting that oceanic circulation patterns might have acted as a cryptic barrier to gene flow.
CONCLUSIONS: Our findings have important implications on the conservation of mangroves, especially relating to replanting efforts and the definition of evolutionary significant units in Rhizophora species. We outlined the genetic structure and identified geographical areas that require further investigations for both R. mucronata and R. stylosa. These results serve as the foundation for the conservation genetics of R. mucronata and R. stylosa and highlighted the need to recognize the genetic distinctiveness of closely-related species, determine their respective genetic structure, and avoid artificially promoting hybridization in mangrove restoration programmes.