Emmclan Lau Sheng Hann, Zakaria Muta Harah, Ramaiya Shiamala Devi, Natrah Ikhsan, Bujang Japar Sidik
Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, UPM Serdang, Selangor Darul Ehsan, Malaysia.
Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, UPM Serdang, Selangor Darul Ehsan, Malaysia.
PeerJ. 2022 Jan 18;10:e12821. doi: 10.7717/peerj.12821. eCollection 2022.
Coastal land development has deteriorated the habitat and water quality for seagrass growth and causes the proliferation of opportunist macroalgae that can potentially affect them physically and biochemically. The present study investigates the morphological and biochemical responses of seagrass from the Hydrocharitaceae family under the macroalgal bloom of , induced by land reclamation activities for constructing artificial islands.
Five seagrass species, , , , and were collected at an -colonized site (MA) shoal and a non--colonized site (MC) shoal at Sungai Pulai estuary, Johor, Malaysia. Morphometry of shoots comprising leaf length (LL), leaf width (LW), leaf sheath length (LSL), leaflet length (LTL), leaflet width (LTW), petiole length (PL), space between intra-marginal veins (IV) of leaf, cross vein angle (CVA) of leaf, number of the cross vein (NOC), number of the leaf (NOL) and number of the leaflet (NOLT) were measured on fresh seagrass specimens. Moreover, water quality and water nutrient content were also recorded. Seagrass extracts in methanol were assessed for total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid radical cation scavenging activity (ABTS), and ferric reducing antioxidant power (FRAP).
Seagrasses in the -colonized site (MA) had significantly higher (-test, < 0.05) leaf dimensions compared to those at the non- colonized site (MC). Simple broad-leaved seagrass of and were highly sensitive to the colonization of , which resulted in higher morphometric variation (-test, < 0.05) including LL, PL, LW, and IV. Concerning the biochemical properties, all the seagrasses at MA recorded significantly higher (-test, < 0.05) TPC, TFC, and ABTS and lower DPPH and FRAP activities compared to those at MC. Hydrocharitaceae seagrass experience positive changes in leaf morphology features and metabolite contents when shaded by . Researching the synergistic effect of anthropogenic nutrient loads on the interaction between seagrasses and macroalgae can provide valuable information to decrease the negative effect of macroalgae blooms on seagrasses in the tropical meadow.
沿海土地开发已使海草生长的栖息地和水质恶化，并导致机会主义大型海藻大量繁殖，这可能会对海草产生物理和生化影响。本研究调查了水鳖科海草在人工岛围垦活动引发的大型海藻爆发下的形态和生化反应。
在马来西亚柔佛州双溪普莱河口的一个有大型海藻定殖的浅滩（MA）和一个无大型海藻定殖的浅滩（MC）采集了5种海草，分别是、、、和。对新鲜海草样本测量了包括叶长（LL）、叶宽（LW）、叶鞘长（LSL）、小叶长（LTL）、小叶宽（LTW）、叶柄长（PL）、叶片边缘内叶脉间距（IV）、叶片交叉叶脉角度（CVA）、交叉叶脉数量（NOC）、叶片数量（NOL）和小叶数量（NOLT）在内的地上部分形态特征。此外，还记录了水质和水体养分含量。对甲醇中的海草提取物评估了总酚含量（TPC）、总黄酮含量（TFC）、2,2 - 二苯基 - 1 - 苦基肼自由基清除活性（DPPH）、2,2'- 偶氮 - 双（3 - 乙基苯并噻唑啉 - 6 -磺酸）自由基阳离子清除活性（ABTS）和铁还原抗氧化能力（FRAP）。
与无大型海藻定殖的浅滩（MC）相比，有大型海藻定殖的浅滩（MA）中的海草叶片尺寸显著更大（t检验，P < 0.05）。和的简单阔叶海草对大型海藻的定殖高度敏感，这导致了更高的形态特征变化（t检验，P < 0.05），包括叶长、叶柄长、叶宽和叶脉间距。关于生化特性，与MC处的海草相比，MA处的所有海草的总酚含量、总黄酮含量和ABTS均显著更高（t检验，P < 0.05），而DPPH和FRAP活性更低。当被大型海藻遮蔽时，水鳖科海草在叶片形态特征和代谢物含量方面经历了积极变化。研究人为养分负荷对海草和大型海藻之间相互作用的协同效应可为减少热带草甸中大型海藻爆发对海草的负面影响提供有价值的信息。
