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- Campus Samambaia, Campus Colemar Natal e Silva, Campus Aparecida de Goiânia.
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Effect of drought stress on the morphological and physicochemical properties of starches from Trimezia juncifolia
(2019-05) Almeida, Viviane Ovidio de; Batista, Karla de Aleluia; Leal, Maria Carolina Bezerra Di Medeiros; Moraes, Moemy Gomes de; Fernandes, Kátia Flávia
In this study corms from Trimezia juncifolia were collected in the wet (WSS) and dry (DSS) seasons and used for extraction of starch. Results evidenced that drought stress interfered with the yield, morphological and physicochemical properties of the starches. In addition, it was observed a higher content of amylose for DSS (44%) when compared with WSS (41%). Drought stress did not interfere with the degree of polymerization (DP) of amylopectin, whereas decreased the amylose DP for DSS. Also, starch granules changed from A-type polymorph in the DSS to a CC-type in WSS. Drought stress reduced the starch crystallinity from 27% in WSS to 25.9% in DSS. In addition, the endothermic transition temperatures and enthalpy change of transition were also affected by drought stress. Finally, results clearly demonstrate that changes in the morphological and physicochemical properties of the starch granules figure as adaptive strategies of T. junciolia to drought stress.
Handbook of standardized protocols for collecting plant modularity traits
(2019-10) Klimešová, Jitka; Martínková, Jana; Pausas, Juli G.; Moraes, Moemy Gomes de; Herben, Tomáš; Yu, Fei-Hai; Puntieri, Javier; Vesk, Peter A.; Bello, Francesco de; Janeček, Štěpán
Plant modularity traits relevant to functions of on-spot persistence, space occupancy, resprouting after disturbance, as well as resource storage, sharing, and foraging have been underrepresented in functional ecology so far. This knowledge gap exists for multiple reasons. First, these functions and related traits have been considered less important than others (e.g., resource economics, organ-based traits). Second, collecting data for modularity traits can be difficult. Third, as a consequence of the previous points, there is a lack of standardized collection protocols. We now feel the time is ripe to provide a solid conceptual and terminological framework together with comparable protocols for plant modularity traits that can be applicable across species, regions and biomes. We identify a suite of 14 key traits, which are assembled into five groups. We discuss the functional relevance of each trait, supplying effective guidelines to assist in the use and selection of the most suitable traits in relation to specific research tasks. Finally, we are convinced that the systematic study and widespread assessment of plant modularity traits could bridge this knowledge gap. As a result, previously overlooked key functions could be incorporated into the functional ecology research-agenda, thus providing a more comprehensive understanding of plant and ecosystem functioning.
Fire and drought: soluble carbohydrate storage and survival mechanisms in herbaceous plants from the cerrado
(2016) Moraes, Moemy Gomes de; Carvalho, Maria Angela Machado de; Franco, Augusto Cesar; Pollock, Christopher John; Ribeiro, Rita de Cassia Leone Figueiredo
The Cerrado biome covers a large area of central Brazil, containing a mosaic of physiognomies determined by soil fertility, seasonal rainfall, and fire. The ground layer vegetation presents a high eudicot diversity and a high proportion of belowground phytomass, represented mainly by a diversity of underground organs storing carbohydrates. Fructans and other soluble carbohydrates are claimed to be more than reserves, conferring protection against abiotic stresses due to osmoregulation properties and rapid turnover. Inulin- and levan-type fructans are prominent and found respectively in the underground organs of Asteraceae and Amaranthaceae, abundant families in the herbaceous Cerrado flora. Poaceae, mainly Panicoideae, is also abundant and accumulates glucose, sucrose, and malto-oligosaccharides, but not fructans, in contrast with temperate grasses. Here, we review evidence that fructans in the herbaceous flora of the Cerrado play a significant role in tolerance to drought and fire, promoting the rapid recovery of the ground-layer vegetation after environmental disturbances.
Elevated efficiency of C3 photosynthesis in bamboo grasses: A possible consequence of enhanced refixation of photorespired CO2
(2021) Peixoto, Murilo de Melo; Sage, Tammy L.; Busch, Florian A.; Pacheco, Haryel Domingos Nogueira; Moraes, Moemy Gomes de; Castro, Tomas de Aquino Portes e; Almeida, Rogério de Araújo; Ribeiro, Dalva Graciano; Sage, Rowan F.
Bamboos are productive grasses that currently yield a high-quality wood and potentially an abundance of lignocellulose for bioenergy. All are C3 grasses of warm habitats, where they are prone to significant photorespiratory inhibition and competitive suppression by C4 grasses. Here, we investigate whether three bamboo species from the Brazilian Cerrado (Dendrocalamus asper, Guadua angustifolia, and Guadua magna) exhibit unique adaptations that suppress photorespiratory costs and enhance photosynthetic efficiency. We evaluated photosynthetic efficiency of the bamboos and rice (Oryza sativa) by measuring C*, the CO2 compensation point in the absence of mitochondrial respiration. At 25℃, C* averaged 2.81 Pa in each of the bamboo species, which is closer to a C2 plant (2.71 Pa) than the C3 plant rice (3.31 Pa). Assuming a chloroplast CO2 concentration of 200 μmol mol−1, this represents an 18% lower cost of apparent photorespiration in bamboo than rice. Light and transmission electronic microscopy of the bamboo leaves exhibited few organelles in the bundle and mestome sheath cells, and mesophyll (M) cells are deeply lobed with 99% of the cell periphery adjacent to intercellular air space covered by chloroplast and stromules. The chloroplast layer in bamboo M cells is thick, with mitochondria adjacent to or engulfed by chloroplasts. This arrangement slows CO2 efflux and facilitates refixation of photorespired CO2, which could explain the low C* in the bamboos. The bamboos also had higher water use efficiency than rice, which may reflect efficient refixation of photorespired CO2.
Leaf anatomy and epicuticular waxes composition of Clusia fluminensis Planch. & Triana (Clusiaceae)
(2017) Virginio, Maria Carolina Anholeti da Silva; Silva, K. M. M.; Moraes, Moemy Gomes de; Santos, Marcelo Guerra; Figueiredo, Maria Raquel; Kaplan, Maria Auxiliadora Coelho; Coutinho, Ana Joffily; Paiva, Selma Ribeiro de
Clusia fluminensis Planch. & Triana (Clusiaceae) is a Brazilian native species found in regions of high luminous intensity and water restriction. There are reports of its use in folk medicine, however, there is little literature information on its chemical composition and structural characterization. The results of the phytochemical study and biological tests conducted by our research group so far have shown that C. fluminensis has great potential to be used as a source of biologically active substances, making its anatomical characterization of fundamental importance. The leaf structure was analyzed through optical microscopy and scanning electron microscopy. The leaves epicuticular waxes were analyzed by GC-MS. The leaf is hypostomatic with paracytic stomata and polygonal epidermic cells with 4 to 7 sides. The epidermis is uniseriate, with cuticle, thicker in the adaxial epidermis with cuticular flanges. The dorsiventral mesophyll showed hypodermis in the adaxial surface and numerous druses all over the mesophyll and many secretory ducts in the mesophyll and midvein. The vascular system is constituted by collateral bundles involved in numerous fibers, which in the midvein are densely grouped. The highest content of epicuticular waxes was obtained from leaves collected in summer. GC-MS data of the waxes indicated a marked presence of triterpenes such as α-amyrin, β-amyrin, lupenone, epifriedelinol and friedelin.