Third Of Stem Research Articles

English

The sesame fruits present differences on maturity due to their position on the plant stem. Thus, the objective of this paper is to evaluate the physiological quality of sesame seeds from three fruits locations on the plant stem (lower, middle and upper thirds) due to fertilizing with cattle manure (0, 20, 40 and 60 t.ha-1). We evaluated the germination percentage, first germination count, germination speed index, average germination time, accelerated-aged seeds germination and electrical conductivity of seeds. In addition, to evaluate seedling establishment we observed emergence percentage, emergence speed index, and average emergence time, as well as length and dry mass of seedlings. The experimental arrange used was entirely randomized in a factorial scheme (3×4) with four repetitions, and means were compared through the Tukey test at 5% probability. The fruits position on the plant stem influenced the sesame seeds quality. The yellowish green fruits from middle third of stem, as well as yellowish ones from lower third of stem showed best results for most variables evaluated. Seed vigor was positively influenced by cattle manure application in the soil; however, fertilizing did not have any effect on seeds germination. Key words: Sesamum indicum L., germination, organic agriculture, seed maturation, seeds vigor.

A Comparative Study of Alfalfa and Medicago truncatula Stem Traits: Morphology, Chemical Composition, and Ruminal Digestibility

Alfalfa (Medicago sativa L.) is an agronomically important forage, but digestibility of stem cell wall material is low. Because the tetraploid genome of alfalfa complicates genetic dissection of complex pathways, the diploid M. truncatula Gaertn. could serve as a model for stem cell wall development in alfalfa. We compared stem morphology, chemical composition (protein, soluble carbohydrates, cell wall polysaccharides, and lignin), and in vitro ruminal cell wall polysaccharide digestibility of two alfalfa clones (Regen‐SY27 and 718) and four M. truncatula inbred lines (A17, A20, DZA315.16, and R108) in a replicated growth chamber experiment. Stem tissue development and cell wall lignification observed by light microscopy were similar between the species. While differences in stem morphology, composition, and digestibility were observed among the germplasms, there was overlap between the alfalfa and M. truncatula germplasms for all traits except protein concentration, which was greater for the two alfalfa clones. Younger stem internodes (top third of the stem) of both species had a higher protein concentration and greater cell wall polysaccharide digestibility, and lower cell wall concentration than older internodes (bottom third of stem). Based on the data presented here, it appears that M. truncatula is a suitable model for stem development, composition, and digestibility of alfalfa.