Determination of resource mobilization during seedling growth of palmyra palm, Borassus flabellifer L

Asian palmyra palm (Borassus flabellifer L.) is a multipurpose tree with year round products as food for the dependent society. Besides edible items the tree offers around 801 useful goods which are economically important. Such a plant’s seedling biology has not been fully understood. Hence, the present study was aimed at understanding seedling developmental stages and resource mobilisation in Palmyra palm and further to determine the role of cotyledonary sheath (CS) during entire seedling growth. We investigated the developmental changes throughout growth of seedlings by providing different sets of growth conditions. Artificial seed bed made of coconut coir was compared with that of soil conditions to study germination and establishment of seedlings. Phloem loading dye was used to track the flow of nutrients from embryo to cotyledonary sheath. Seed germination in palmyra palm is hypogeal by forming ligular and tubular structures remotely in soil. Eight new organs differentiate from the seed embryo that includes haustorium, ligule, cotyledonary sheath, cataphyll, eophyll, mesocotyle (junction), primary root and mesocotyl roots during seed germination. Among these the first four are temporary organs and they disintegrate once the seedling is well established. The last four organs are responsible for developing acomplete plantlet at later stages. The seed and seedling organs of Palmyra palm have four major storage reserves to support successful germination and firm establishment of seedling. Palmyra has evolved to control the solubilisation, movement and regulation of food among transient seedling organs and carry out translocation of food to the developing and differentiating organs. Seedlings also have developed physiological functions and strategies to mobilise the stored food without losing them at any point of their growth and developmental stages. Water required for seed germination permeates laterally only viacotyledonary sheath which has spongy tissues and lenticels all over. These tissues are the primary mode of water supply as the seedlings lack major root organs in the early stages of development. Flourescent microscopic and anatomical studies were carried out to observe the transport and storage of food substances required during seedling growth. Histochemical studies of seedling organs have revealed the presence of various type of nutrients such as simple sugars, carbohydrates, proteins, amino acids and lipids.

Morphoanatomy of Serjania communis Cambess. seedling (Sapindaceae) / Morfoanatomia da plântula de Serjania communis Cambess. (Sapindaceae)

Serjania communis Cambess. (Sapindaceae) is a plant with climbing habit and occurs relatively often in Paraná State, Brazil. The fruits were collected at the 'Parque dos Pioneiros' a remnant of subtropical forest in Maringá, Paraná State, Brazil. The seedlings obtained in the greenhouse were described according to traditional techniques in plant morphology. Seedlings were embedded in historesin and sectioned in rotation microtome. The fruit is the samaroid type, the seeds have about 3 mm in length and brown color. Seedlings are epigeal phanerocotylar. The seedlings have a hairy hypocotyl, foliaceous cotyledons, reduced epicotyl, and two opposite eophylls. The root is diarch, the hypocotyl shows root-stem transition structure, stem epicotyl, and dorsiventral and hypostomatous cotyledons and eophylls. 'Tirodendros' with 45 days of age do not develop cambial variant.

Serjania communis Cambess. (Sapindaceae) é uma planta de hábito lianescente e ocorre com relativa frequência no Estado do Paraná, Brasil. A coleta dos frutos para a obtenção de sementes foi realizada no parque florestal dos Pioneiros (bosque II), um remanescente de floresta subtropical de Maringá, Estado do Paraná, Brasil. As plântulas, obtidas em casa de vegetação foram descritas conforme técnicas usuais em morfologia vegetal. Após a germinação, as plântulas foram descritas morfoanatomicamente e também foi verificada se ocorria a instalação de variante cambial nesta fase inicial de desenvolvimento. O fruto é do tipo samaroide. As sementes têm cerca de 3 mm de comprimento, de cor marrom e com germinação epigeia e as plântulas são fanerocotiledonares. As plântulas foram emblocadas em historresina e secionadas em micrótomo de rotação. As plântulas apresentam o hipocótilo piloso, cotilédones foliáceos, o epicótilo é reduzido, os dois primeiros eofilos são opostos e os demais eofilos apresentam filotaxia alterna helicoidal. A raiz é diarca. O hipocótilo é uma região de transição raiz-caule. O epicótilo tem estrutura caulinar eustélica. Os cotilédones e os eofilos são hipostomáticos e dorsiventrais. Tirodendros com 45 dias de idade não desenvolvem variante cambial.

Morphology and anatomy of the seedling and the tirodendro of Calophyllum brasiliense Cambess. (Clusiaceae) / Morfoanatomia da plântula e do tirodendro de Calophyllum brasiliense Cambess. (Clusiaceae)

Calophyllum brasiliense Cambess. is a tree species that is presented as an alternative to replace endangered species of hardwood. The morphology and anatomy of the seedling of this species is the object of the present study. Seedlings at different stages of development were obtained in greenhouse and analyzed fresh and fixed in FAA (Formalin- Acetic-Alcohol) 50. The anatomical analysis was done by the freehand and microtome sections, according to standard techniques in plant anatomy. The seedling and/or tirodendro is cryptocotylar and hypogeal, has cataphylls, and presents eophylls and metaphylls simple with venation pinnate craspedodromous simple. The root is polyarch, the hypocotyl is very short, the cotyledons have an oily and starchy reserve, the epicotyl has stem structure, and eophylls and metaphylls are dorsiventral. The seedling may be classified in the Horsfieldia type/subtype.

Calophyllum brasiliense Cambess. é uma planta arbórea que se apresenta como possível alternativa para substituir espécies em extinção com madeira nobre. A morfologia e anatomia da plântula desta espécie é objeto do presente trabalho. As plântulas, em diferentes fases de desenvolvimento, foram obtidas em casa de vegetação e analisadas a fresco e fixadas em FAA 50. A análise anatômica foi feita mediante seções a mão livre e microtômicas, de acordo com técnicas usuais em anatomia vegetal. A plântula e/ou tirodendro é criptocotiledonar e hipogeia, possui catafilos, e apresenta eófilos e metafilos simples de venação pinada craspedódroma simples. A raiz é poliarca, o hipocótilo é muito reduzido, os cotilédones possuem reserva amilácea e oleaginosa, o epicótilo tem natureza caulinar e os eofilos e metafilos são dorsiventrais. A plântula enquadra-se no tipo e subtipo Horsfieldia.

Effect of soil contaminated by diesel oil on the germination of seeds and the growth of Schinus terebinthifolius Raddi (Anacardiaceae) Seedlings

The effect of soil polluted by diesel oil on the germination of seeds and the growth of Schinus terebinthifolius Raddi seedlings was analyzed at different times after contamination of the soil. The experiments were conducted under greenhouse conditions, with four treatments and five repetitions. The four treatments included: soil contaminated 30 (T30), 90 (T90) or 180 (T180) days before planting as well as a non-polluted soil (T0) (control). Soil saturated to 50 percent of its maximum retention capacity (MRC) was contaminated with diesel oil at a rate of 92.4 mL per kg. The germination rate and germination speed index (GSI) were significantly affected only in T30. The development of the plants was affected significantly in all the treatments, with reductions of biomass and eophyll area. It could be concluded that diesel oil significantly affected the germination, GSI and seedling growth of S. terebinthifolius, but the toxic effect decreased over the time.

Semi-hypogeal germination in Pachyrhizus ahipa (Wedd.) parodi (Fabaceae: Phaseoleae): seedling and sapling morphology

The aim of this work was to describe the morphology of seedlings and saplings of Pachyrhizus ahipa, a cultivated species of Phaseoleae (Fabaceae), analysing the seedling type and characterizing the structure of cotyledons, eophylls and metaphylls. It was observed that the seedling was semi-hypogeal, a germination type not yet recorded for the Phaseoleae tribe. It formed two opposite and unifoliated eophylls with an evident pair of stipels. Metaphylls were trifoliolate and had alternate phyllotaxis. Both eophylls and metaphylls were pinnate, camptodromous, and brochidodromous.

É de conhecimento geral que existe grande escassez de estudos referentes às fases juvenis das plantas, importantes como subsídio para diversos trabalhos ecológicos, taxonômicos e filogenéticos. Com base nesse pressuposto, descreveram-se morfologicamente plântulas e plantas jovens de Pachyrhizus ahipa, espécie cultivada de Phaseoleae (Fabaceae), analisando-se o tipo de plântula e caracterizando estruturalmente os cotilédones, eofilos e metafilos. Verificou-se que a plântula é semi-hipógea, tipo de germinação até então não registrado para a tribo Phaseoleae. A plântula forma dois eofilos unifoliolados e opostos, acompanhados por evidente par de estipelas. Os metafilos são trifoliolados, de filotaxia alterna. Tanto eofilos quanto metafilos são pinados, camptódromos e broquidódromos.