Growth and physiological characteristics of the weed false johnsongrass ( Sorghum arundinaceum (Desv.) Stapf)

Abstract

RESUMOSubmitted on 03/27/2014 and approved on 10/20/2015 Sorghum arundinaceum (Desv.) Stapf a weed that belongs to the Poaceae family and is widespread throughout Brazil. Despite the frequent occurrence, infesting cultivated areas, there is little research concerning the biology and physiology of this species. The objective of this research was to evaluate the growth, carbon partitioning and physiological characteristics of the weed Sorghum arundinaceum in greenhouse. Plants were collected at regular intervals of seven days, from 22 to 113 days after transplanting (DAT). In each sample, we determined plant height, root volume, leaf area and dry matter, and subsequently we performed the growth analysis. We have determined the dry matter partitioning among organs, the accumulation of dry matter, the specific leaf area, the relative growth rate and leaf weight ratio. At 36, 78 and 113 DAT, the photosynthetic and transpiration rates, stomatal conductance, CO 2 concentration and chlorophyll fluorescence were evaluated. The Sorghum arundinaceum reached 1.91 m in height, with slow initial growth and allocated much of the biomass in the roots. The photosynthetic rate and the maximum quantum yield of FSII are similar throughout the growth cycle. At maturity the Sorghum arundinaceum presents higher values of transpiration rate, stomatal conductance and non-photochemical quenching coefficient (NPQ).Key words: growth analysis, gas exchange, chlorophyll a fluorescence. Crescimento e características fisiológicas da planta daninha falso-massambará (Sorghum arundinaceum (Desv.) Stapf) Sorghum arundinaceum (Desv.) Stapf é uma planta daninha pertencente à família Poaceae e encontra-se disseminada em todo o território brasileiro. Apesar da ocorrência frequente, infestando áreas cultivadas, são poucas as pesquisas concernentes à biologia e à fisiologia desta espécie. Objetivou-se com esta pesquisa avaliar o crescimento, a partição de fotoassimilados e as características fisiológicas da planta daninha Sorghum arundinaceum, em casa de vegetação. As plantas foram coletadas em intervalos regulares de sete dias, a partir de 22 e até 113 dias após o transplantio (DAT). Em cada coleta, determinaram-se altura de plantas, volume de raiz, área foliar e massa seca e, posteriormente, aplicou-se a análise de crescimento, sendo calculada a partição de massa seca entre os órgãos, o acúmulo de massa seca, a área foliar específica, a taxa de crescimento relativo e a razão de peso foliar. Aos 36, 78 e 113 DAT foram avaliadas as taxas fotossintética e transpiratória, a condutância estomática, a relação entre a concentração 17 Growth and physiological characteristics of the weed false johnsongrass (Sorghum arundinaceum... Deborah Amorim Martins

O manejo de cortes modifica o filocrono, o crescimento e a produção do sorgo forrageiro sob ambiente de temperatura amena

“…The crop was favored by high temperature weather conditions. This result corroborates with Houx and Fritschi (2015) and Martins et al (2016).…”

“…FWR had similar behavior with LAR ( Figure 2G), and represents that as the plant grows, it stops investing so much in the leaves and reduces the photosynthetic area useful for export to the other drains. These results corroborate with Zuffo et al (2016); Martins et al (2016). As mentioned above, the plants of the uncut treatment also had its FWR diminished and the other treatments increased this rate after each cut, with the development of the new leaves.…”

Growth Analysis of Chloris elata

“…C. elata, in another study, also presented a slow initial growth and development, as well as a remarkable final dry matter accumulation (Carvalho et al, 2005a). The same result was observed for plants of Digitaria insularis and Sorghum arundinaceum, both perennial species from the family Poaceae, which also showed a slow initial growth until the 45th and 57th days after transplanting, respectively (Machado et al, 2006;Martins et al, 2016).…”

“…Growth analysis is an accessible and accurate method to infer the contribution of different physiological processes to the behavior of plants; around 90% of the dry matter accumulated by plants along their growth comes from photosynthetic activity, and the rest results from the absorption of mineral nutrients (Benincasa, 2003). In addition, growth analysis represents the initial reference in the analysis of the production of plant species, and its use requires information that can be obtained without the need for sophisticated equipment (Machado et al, 2006), making it possible to understand the physiological responses and morphological characteristics of plants, in relation to environmental factors and their effects on the ecological niche (Martins et al, 2016).…”

Fitossociologia Em Pomares De Mangueira Irrigados Por Gotejamento E Microaspersão Em Condições Semiáridas

“…De acordo com Martins et al (2016) o S. arundinaceum possui características fisiológicas e de crescimento semelhantes a outras gramíneas invasoras que apresentam metabolismo de C4, requerendo assim, atenção no manejo desta invasora especialmente em cultivos de verão e nos estágios iniciais de estabelecimento das culturas. As demais espécies encontradas no pomar irrigado por microaspersão foram Ipomoea purpurea, Chloris barbata, Crotalaria sp.…”