Ecological anatomy of Eugenia luschnathiana (O.Berg) Klotzsch ex B.D.Jacks. (Myrtaceae) leaves in the Restinga region, state of Ceara

Abstract Eugenia luschnathiana (O.Berg) Klotzsch ex B.D.Jacks. (Myrtaceae) species, commonly known as pitomba-da-baía, occurs in Restinga region in the state of Ceara and has medicinal potential. The present study aimed to characterize the anatomy of E. luschnathiana leaves in the rainy and dry seasons, as well as in the sun and shade in the Restinga region of Ceara, aiming to generate useful information to understand the adaptive value of morphoanatomic responses to the natural conditions of occurrence of the species. Collections were performed at the State Botanical Park of Ceara, and leaves were completely expanded and fixed in FAA70, being replaced by 70% ethanol after 24 h. Samples were submitted to standard plant anatomy methodologies in order to qualitatively and quantitatively analyze the leaf blade and petiole structures. As a result, there were differences among sun and shade leaves, rain and dry. In relation to luminosity, most determinations were higher in sun leaves: trichome density and frequency; trichome scar frequency; stomatal frequency, stomatal index, length, width and area of stomata; thickness of leaf blade, mesophyll, cuticle, epidermis, palisade and spongy parenchyma; length and width of the central vein, area of the central vein vascular bundle, number of secretory cavities in the central vein; length and width of the petiole, area of the petiole vascular bundle; amount and area of secretory cavities in the petiole. In shade leaves, only the number of druses in the central vein and petiole were larger. Regarding seasonality, all determinations were higher in the rainy season, except for the length and width of the central vein; number of druses in the central vein and petiole; length of the petiole, area of the vascular bundle and secretory cavities of the petiole. Therefore, it could be concluded that E. luschnathiana has great acclimative capacity to conditions of intense luminosity and periods of water deficit.

摘要 巴西番樱桃（Eugenia luschnathiana (O.Berg) Klotzsch ex B.D.Jacks.，桃金娘科Myrtaceae）俗称巴伊亚皮通巴果（pitomba-da-baía），自然分布于塞阿拉州的海滨沙原（Restinga）生境，且具有药用开发潜力。本研究以该物种为研究对象，旨在解析塞阿拉州海滨沙原生境下，其叶片在雨季、旱季以及阳生、阴生条件下的解剖结构特征，以期为理解该物种形态解剖响应对其自然分布生境的适应价值提供科学依据。样本采集于塞阿拉州立植物园，选取完全展开的成熟叶片，经70% FAA固定液固定24小时后更换为70%乙醇保存。采用标准植物解剖学方法对叶片与叶柄结构开展定性与定量分析。结果显示，阳生叶与阴生叶、雨季叶与旱季叶均存在显著差异。就光照条件而言，阳生叶的多数检测指标均更高：包括表皮毛密度与出现频率、表皮毛痕频率、气孔频率、气孔指数、气孔长度、宽度及面积；叶片厚度、叶肉厚度、角质层厚度、表皮厚度、栅栏组织与海绵组织厚度；主脉长度与宽度、主脉维管束面积、主脉分泌腔数量；叶柄长度与宽度、叶柄维管束面积、叶柄分泌腔数量与面积。而阴生叶仅主脉与叶柄中的草酸钙晶簇数量更多。就季节变化而言，雨季采集的叶片各项检测指标均更高，仅主脉长度与宽度、主脉及叶柄中的晶簇数量、叶柄长度、叶柄维管束面积与分泌腔面积除外。综上可知，巴西番樱桃对强光环境与水分亏缺时期具备较强的适应能力。