Root Dry Matter Weight Research Articles

Seed quality, chlorophyll content index and leaf nitrogen levels in maize inoculated withAzospirillum brasilense

The aim of this study was to evaluate differences between maize genotypes in relation to the germination response of the seeds and the growth of seedlings inoculated with Azospirillum brasilense, as well as the effect of inoculation on nitrogen levels and the chlorophyll content index of the leaves. The physiological seeds quality from the single-cross hybrids AG7098 and 2B707, and from the experimental synthetic varieties V2 and V4, inoculated with A. brasilense, was tested for germination, percentage and rate of emergence, and dry matter weight of the shoots and roots. Nitrogen levels and chlorophyll content index were evaluated in leaves of the same four genotypes grown in a greenhouse under different nitrogen supply systems and methods of inoculation with A. brasilense. The genotypes differ with regard to inoculation with A. brasilense. The hybrids were responsive to inoculation with A. brasilense for root dry matter weight. The V2 variety had a lower performance as regards root dry matter weight, with the opposite being seen for the dry matter weight of the shoots. V4 displayed no significant differences when inoculated. The results of the chlorophyll content index were not significant. Each genotype under evaluation displayed a different response for leaf nitrogen levels. It is possible to infer that the hybrids responded better to inoculation with the bacteria, with the greater root development leading to a better utilisation of water and nutrients.

Iron efficiency of different corn hybrids grown in nutrient solution culture

Growing Fe-efficient genotype(s) could be considered as a preferred genetic approach to tackle the widespread constraint of Fe-deficiency-/lime-induced chlorosis in crop grown on alkaline soil. This study aimed to investigate morphological and physiological traits linked to expression of Fe deficiency among four corn (Zea mays) including sweet (Z. mays sacchrata cvs. H403 and H404) and grain (Z. mays indentata cvs. H500 and H700) hybrids grown in nutrient solution using two Fe concentrations (5 and 50 µM Fe-ethylenediaminetetraacetic acid (Fe-EDTA)). Significant variation was found among studied hybrids in their tolerance to Fe-deficiency stress. Sweet corn hybrids were more sensitive to Fe deficiency as compared with grain corn hybrids and greater reduction was observed in their shoot dry matter at the 5 µM Fe-EDTA treatment. The greatest decrease in plant height, leaf area, and root and shoot dry matter weight under Fe-deficiency condition was found for H403 hybrid. No significant correlation was found between shoot and root Fe concentration with crop tolerance to Fe deficiency. Furthermore, different response of corn hybrids to Fe deficiency is an important factor, which has to be considered in Fe fertilizer recommendation as well as breeding programs.

Root Distribution and Nitrogen Fixation Activity of Tropical Forage Legume American Jointvetch (Aeschynomene americanaL.) cv. Glenn under Waterlogging Conditions

We investigated the root distribution and nitrogen fixation activity of American jointvetch (Aeschynomene americanaL.) cv. Glenn, under waterlogging treatment. The plants were grown in pots under three different treatments: no waterlogging (control), 30 days of waterlogging (experiment 1), and 40 days of waterlogging (experiment 2). The plants were subjected to the treatments on day 14 after germination. Root dry matter (DM) weight distribution of waterlogged plants was shallower than controls after day 20 of waterlogging. Throughout the study period, the total root DM weight in waterlogged plants was similar to that in the controls. Enhanced rooting (adventitious roots) and nodule formation at the stem base were observed in waterlogged plants after day 20 of waterlogging. The average DM weight of individual nodules on the region of the stem between the soil surface and water surface of waterlogged plants was similar to that of individual taproot nodules in the controls. Waterlogged plants had slightly greater plant DM weight than the controls after 40 days of treatment. The total nitrogenase activity (TNA) of nodules and nodule DM weight were higher in waterlogged plants than in the controls. Waterlogged American jointvetch had roots with nodules both around the soil surface and in the area between the soil surface and water surface after 20 days of waterlogging, and they maintained high nitrogenase activity and net assimilation rate that resulted in an increased growth rate.

Phytotechnical aspects of rooted stem cuttings of coffee.

The cloning of F1 Coffea arabica hybrids may represent a significant decrease in time and resources spent on coffee plant improvement programs. With the objective to obtain a methodology that allows an efficient cloning of C. arabica L. plants through stem cutting, two experiments were carried out in a green house with automatic mist system. In the experiment Rubi cultivars cuttings were used. The efficiency of root bed heating, exogenous sucrose supply (30 g.L-1), and six concentrations of IBA on the rooting of cuttings and formation of seedlings was tested. The evaluations were carried out 45, 90 and 180 days after installation. The results showed that sucrose did not have a positive effect on any of the analyzed variables. The root bed heating was effective for the ‘Rubi’. Bed heating associated with IBA did not increase the total percentage of ‘Rubi’ rooted cuttings. Nevertheless it increased the number of roots, root and shoot dry matter weight.

Improving effects of mycorrhizal symbiosis on sorghum bicolor under four levels of drought stress

This study was conducted to determination the symbiotic effects of arbuscular mycorrhizal (AM) fungi on the shoot and root characteristics and mycorrhiza influence on relationships between minerals (phosphorus and Nitrogen) acquisition and yield components under drought stress in Sorghum bicolor. A pot experiment was carried out in Shiraz, Iran in 2010 growing season. The experiment was conducted using split-plot arrangements in a randomized complete block design (RCBD) with three replications. Treatments were based on drought stress in four levels and mycorrhiza infection stages consisted of mycorrhiza inoculated (M1) and non-mycorrhiza (M0). The results showed that the drought stress had significant influences on root colonization percent, shoot dry matter weight, plant height, leaf area, root dry matter weight, root/shoot ratio, root length and root wet weight. It seems to be that the mycorrhiza had visibly increased the biomass of sorghum by impacts on the root characteristics, such as: root weight, root length, and root/shoot ratio. The cluster analysis indicated that shoot dry matter weight was correlated with root dry matter weight in non-mycorrhizal condition. Plant height and root length traits were also correlated with leaf area and root wet weight. While, these relations changed in mycorrhizal condition and plant height, leaf area, root wet weight and root length were correlated with root colonization percent. Also cluster analysis indicated the great improvement in relations between morphological traits and nutrients absorption and yield components by effects of mycorrhizal inoculation.

Effects of different soil textures on the growth and distribution of root system and yield in peanut

Aims This paper explores soil types to suit the development of root system and improve the yield of peanut (Arachis hypogaea). Methods We used the method of box-planted cultivation to study the effects of different soil textures, i.e., sandy, loam and clay soils, on the development and distribution of root system and yield of peanut. Important findings Root dry matter weight of peanut in sandy and loam soils was higher significantly than in clay soil; however, in the later growth stage, the decrease of root dry matter weight of peanut in clay soil is relative slow compared with peanut in loam and sandy soil. In clay soil, the root system of peanut was mainly distributed in the shallow soil layer, but the decrease of root activity in the upper layers was much slower in the late growth period. Sandy soil was helpful for the root system of peanut to grow to the deeper soil layer, but the decrease of root activity in the surface layers was faster in the later growth period. The effects of loam soil on the spatial and temporal distribution of the development and activity of peanut roots were between sandy and clay soil. Sandy soil favored enlargement of the peanut pod, and the dry matter accumulation of peanut pod in sandy soil was earlier and faster, but the dry matter accumulation in the later growth period was less in sandy soil. In loam soil, the dry matter accumulation of peanut pod was mainly concentrated in middle and later periods, while clay soil was not suitable for the dry matter accumulation of peanut pod in the entire growth period. The pod yield, kernel yield and available pod number were largest in loam soil, second in sandy soil and lowest in clay soil. Results suggested that loam soil, with mid-levels of aeration and water and fertilizer conservation among the three soil textures, was most suitable for the growth and yield of peanut.

Development of a Method for Testing Dehydration Tolerance in Rice (Oryza sativa L) and its Application to a Recombinant Inbred Line Population

A recombinant inbred line population derived from Japonica rice cultivar Hyogokithanishiki and Indica rice cultivar Hokuriku-142 is a valuable source for genetic and molecular studies as these two parents have different origins. Characterization of the two parents under different biotic and abiotic stress conditions exploits novel research areas such as QTL analysis. In the present study two parents were evaluated for dehydration tolerance using Petri dish method and nursery box method. Average root length, shoot length, root dry matter and shoot dry matter weight were evaluated in each method. Shoot length in nursery box method gave a significant difference between two cultivars with Hygokithanishiki dehydration tolerant and Hokuriku-142 dehydration susceptible. The method was applied to evaluate 163 recombinant inbred lines (RILs) derived from the two parents for dehydration tolerance. The trait showed a normal distribution in the population with some transgressive lines expressing greater dehydration tolerance than dehydration tolerant parent Hyogokithanishiki. Therefore nursery box method is proposed as a reliable method for the evaluation of dehydration tolerance of rice cultivars and this method is suitable for evaluating germplasm collections and breeding populations for dehydration tolerance in rice breeding. DOI: http://dx.doi.org/10.4038/tare.v14i3.4846 Tropical Agricultural Research & Extension 14(3): 2011 76-82

Effect of Moringa oleifera leaf aqueous extract on growth and yield of rape and cabbage

The potential effect of Moringa oleifera leaf extract on growth and yield of cabbage (Brassica oleracia L. var. capitata) and rape (Brassica napus L. var. Giant rape) was evaluated. In the greenhouse, five treatments were used: the control, where only water was added (M0), second control where ethanol 80% was added (ME), Moringa leaf extract applied once at two weeks from emergence (M1), Moringa leaf extract applied at two and four weeks from emergence (M2), and Moringa extract applied every two weeks to maturity, starting from two weeks from germination (M3). The same treatments were adopted in the field except the ME which was considered unnecessary after observing the results of the greenhouse experiment. Results show that Moringa leaf extract significantly increased above ground dry matter yield (DM), root dry matter weight and plant height for the two crops. Yields obtained at MI, M2 and M3 were increasing in ascending order from M1. Highest DM, root weight, height and crop yields in the greenhouse and field experiments were obtained at M3. The study recommends the application of extract at M3. Key words: Moringa oleifera, dry matter, cabbage, rape, greenhouse.

Effect of planting methods and vine harvesting on shoot and tuberous root yields of sweet potato [Ipomoea batatas (L.) Lam.] in the Afar region of Ethiopia

In the arid pastoralist Afar region of Ethiopia, scarcity of food and fodder owing to recurring droughts is a major problem imperilling livestock and human survival. Therefore, sweet potato production as a dual purpose food-security crop has been steadily increasing in the region. However, there is scarcity of information on agronomic practices that may lead to optimum production of tuberous roots and shoots. Therefore, a field experiment was conducted at Werer Agricultural Research Centre with the objective of evaluating the influence of planting methods and vine harvesting time on yields of tuberous roots and shoots of the crop plant. The treatments consisted of three planting methods (ridge, flat, and sunken), and three vine harvesting times (45, 75 and 105 days after planting including one control treatment without vine harvesting). The experiment was laid out as a randomized complete block design in a factorial arrangement and replicated four times. The results revealed that planting sweet potato on ridges and harvesting the vines 105 days after planting (when about 60% of the growth phase of the plant was completed) led to optimum production of herbage for fodder without compromising yield of tuberous roots. Key words: Planting method, shoot (vine) yield, tuberous root weight, tuberous root dry matter weight, tuberous root number, vine harvesting.

Propagation through cutting technique of species ocurring in the Lower São Francisco River in Sergipe State with different concentrations of indolbutiric acid

The objective of this work was to evaluate the feasibility of vegetative propagation through cutting technique of seven tree species with strong occurrence in the riparian forest of the Lower São Francisco River in Sergipe State, under different concentrations of indolbutiric acid at 0, 2500, and 5000 mg.L-1, for potentialization of its use in soil bioengineering technique. It was used a complete random block design with three replicates, and a total of twenty-one treatments. The evaluation period was 120 days for each species, and the data collection was made in intervals of fifteen days, in a total of eight evaluations for each species. The evaluated parameters were: Survival Rate, callus formation, and Root Dry matter Weight. Among the studied species, Schinus terebinthifolius Raddi presented the best results related to cutting technique mainly under the indolbutiric acid concentration of 2500 mg.L-1.

Effects of planting dates, fertilization with N and irrigation mode on morphological and phenotypic traits of sugar beet seedlings

In this study we tested the effects of two planting dates, fertilization with N and lack of fertilization, as well as two different irrigation modes on morphological and phenotypic traits of sugar beet seedlings. Well-developed sugar beet seedlings are thought to be cultivated plants whose requests comply with agroecological conditions of the region. We tested number of plants per ha, root diameter, root fresh weight, number of leaves aboveground fresh weight, aboveground dry matter weight, and root dry matter weight. Analysis of variance of a three-factorial trial in three research years showed significant impact of the first planting date on all observed morphological and phenotypic traits of sugar beet seedlings. N fertilization applied before planting provided justified higher difference when compared to control, regarding root fresh weight, aboveground fresh weight and larger root diameter. Different irrigation modes provided significantly higher number of plants and root fresh weight.

Root Exudates and Nitrogen Uptake of Wheat in Wheat/Maize/Soybean Relay Cropping System

Root exudates play a role in adjusting physical and chemical characteristics of soil, improving soil fertility, and facilitating nutrient uptake. Thus, they are used to explaining the mechanism of high nutrient utilization efficiency for plants. In the relay cropping system of wheat/maize/soybean, nitrogen use efficiency appears higher than that in the cropping system of wheat/maize/sweet potato. For explaining the relationship between the high use efficiency of nitrogen and the effects of rhizosphere microenvironment in the wheat/maize/soybean cropping system, the characteristics of wheat root exudates as well as its effects on wheat roots, wheat rhizosphere soil, and nitrogen uptake in wheat were studied in a two-year continuous experiment from 2006 to 2008 with four cropping systems, including two sole cropping systems (wheat–soybean and wheat–sweet potato) and two rely cropping systems (wheat/maize/soybean and wheat/maize/sweet potato). In the wheat/maize/soybean system, the soil moisture, soil pH and soil quick-acting N (NO3?-N and NH4+-N) content at wheat rhizosphere reduced at both flowering and ma-turity stages, and the total nitrogen uptake in shoots, root activity, root dry matter weight and soil total nitrogen content of wheat increased. At flowering stage, the total amount of organic acids and the content of soluble sugar of wheat rhizosphere increased in the wheat/maize/soybean system. The total amount of organic acid and the content of soluble sugar of wheat were higher in relay cropping system than in sole cropping system. In the two sole cropping systems, the wheat–soybean mode had higher amount of organic acid and higher content of soluble sugar than wheat–sweet potato. Wheat plants from fringe rows could exude organic acids and higher soluble sugar content than those from central rows, and the amount of root exudates in fringe rows was the high-est among all the cropping systems. At jointing stage, the content of acetic acid in the sole cropping systems increased, which accounted for 47.8% to 51.6% of the total of organic acid. The content of citric acid in the relay cropping systems increased from 31.7% to 55.1% of total organic acid. At flowering stage, the content of acetic acid in sole and relay cropping systems was also promoted from 33.3% to 78.3% of the total organic acid. The root exudates were in favor of improving root growth condition, activating soil nutrition, enhancing nitrogen uptake and increasing nitrogen use efficiency in the wheat/maize/soybean relay crop-ping system.

Crescimento e micorrização de genótipos de milho em casa de vegetação

O trabalho foi desenvolvido em casa de vegetação com o objetivo de comparar o crescimento e a micorrização por fungos micorrízicos arbusculares (FMA) em nove genótipos de milho, além de verificar o potencial de inóculo de FMA do solo. Coletado de uma área de cerrado sensu stricto ocupada por pastagem degradada, o solo foi adubado, misturado com areia de rio, fumigado e colocado em sacos plásticos (3 kg). Foram semeadas cinco sementes de cada genótipo de milho em 20 sacos, mas apenas 10 receberam cerca de 300 esporos de FMA, coletados do solo de pastagem. Cada saco constituiu-se em uma repetição, com apenas uma planta. As avaliações de altura e diâmetro do caule foram realizadas aos 15, 30, 45 e 60 dias após a emergência, além de massa seca do sistema radicular (MSR) e parte aérea (MSPA), colonização micorrízica (COL) e dependência micorrízica (DM). Concomitantemente, um segundo experimento foi realizado para avaliar o potencial de inóculo de FMA do solo de pastagem, o qual passou por uma diluição seriada de 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20% e 10%, incluindo apenas o solo não esterilizado (100%) e somente solo esterilizado (0%), em sacos plásticos, semeado o híbrido Tractor. Após 60 dias, as raízes foram colhidas para quantificar a colonização micorrízica. A inoculação de FMA acarretou incrementos na produção de matéria seca de forma diferenciada entre genótipos; com Condá, F0, D1 e F8 exibindo os maiores valores de MSPA, enquanto Tractor e D7 os menores valores de MSR. Os genótipos não responsivos ou pouco responsivos quanto à dependência micorrízica tiveram comportamento diferente quanto à COL, com Condá, Sol da Manhã, F0 e D1 proporcionando média de 60%. Verificou-se que a área de pastagem, mesmo degradada, propiciou alto potencial de inóculo, revelado pela alta porcentagem de colonização das raízes por FMA.

Alterações em algumas propriedades de um latossolo degradado com uso de lodo de esgoto e resíduos orgânicos

A recuperação de áreas muito impactadas, como as oriundas da construção de hidrelétricas, é um processo lento e, usualmente, requer a adição de resíduos orgânicos, como fonte de matéria orgânica, e de nutrientes, como condicionador das propriedades do solo. O objetivo deste trabalho foi verificar o efeito da adição de lodo de esgoto e resíduos orgânicos (maravalha e torta de filtro de cana-de-açúcar) sobre o crescimento de duas espécies arbóreas de Cerrado na recuperação de um subsolo de uma área degradada pela construção da Usina Hidrelétrica de Ilha Solteira, localizada em Selvíria - MS. O experimento foi conduzido em casa de vegetação em delineamento experimental inteiramente casualizado, com oito tratamentos, seis repetições e uma planta por repetição, para cada planta-teste. Cada repetição (saco plástico) teve 3,3 L e as proporções em volume da mistura de cada resíduo foram de: 30 % de lodo de esgoto, 20 % de torta de filtro e 10 % de maravalha de madeira. Foram mensuradas a fertilidade, a micorrização, a atividade microbiana (C-CO2 liberado) do subsolo, a massa do sistema radicular e parte aérea e a altura de plantas de duas espécies nativas do Cerrado [monjoleiro (Acacia polyphylla DC.) e jatobá-do-Cerrado (Hymenaea stigonocarpa Mart)]. Os tratamentos com lodo de esgoto proporcionaram maior atividade microbiana no substrato e maior crescimento para as duas espécies arbóreas. A presença do lodo de esgoto promoveu melhora na fertilidade do subsolo, com aumento dos teores de matéria orgânica, P, K, Ca e Mg. A matéria orgânica e o P tiveram seus teores elevados nos tratamentos com mistura de lodo de esgoto e demais resíduos. Os resultados permitem concluir que as misturas contendo lodo associado a resíduos promoveram melhores incrementos na qualidade do subsolo, com perspectivas de sua recuperação.

EFFECTS OF LATITUDE IN MORPHOLOGICAL AND PHYSIOLOGIC PARAMETERS AND PLANT HARVEST INDEX IN FRESH PLANTS OF STRAWBERRY CV. 'CAMAROSA'

The production of early strawberries in Argentina is situated in the north of the country under a humid subtropical regime. Fresh plants are being grown at nurseries located both at high and low latitudes. The purpose of this study was to determine the effect of latitude on plant development and Plant Harvest Index (PHI) = (dry weight root + dry weight crown)/(total dry weight) x 100 strawberry cv. 'Camarosa'. The nurseries were located in low latitude (Tafi of Valley, 2200 m a.s.l.) and high latitude (Esquel, 789 m a.s.l., 42°56'S.L., and Los Antiguos 46°35'20S.L). The plants were grown in 2005/2006 and were harvested in the first week of April 2006. Under low latitude conditions dry matter weight, petiole and leaflet were higher; PHI was higher (49.223; 47.314) in high latitude compared with low latitude (34.877). Latitude had no effect on crown dry wt expressed as % of total plant dry wt, but root dry wt expressed as % of total plant dry wt was significantly reduced (24.1%) at the low latitude site compared to either high latitude site (37.5% and 35.7%), respectively to low latitude (24.1%). A correlation was found between PHI and root dry matter weight. A non-significant correlation was found with the dry matter weight in the crowns. These results suggest that factors such as photoperiod and temperature are determining the physiological maturity of the plants. The study revealed that the latitude, existing out of the temperature and photoperiod component, contributes significantly to the increase in dry matter in the roots.

Produção de mudas de mamoeiro utilizando Bokashi e Lithothamnium

O trabalho teve o objetivo avaliar o crescimento de mudas de mamoeiro do grupo Solo, sob diferentes doses dos fertilizantes naturais bokashi e pó de algas marinhas (Lithothamnium sp). O substrato utilizado foi a mistura de terra, areia e composto orgânico (3:2:1, v/v). Os tratamentos consistiram de quatro doses do fertilizante bokashi (0; 3; 6; 10%, v/v) e quatro doses do fertilizante lithothamnium (0; 3; 6; 10 g L-1), adicionados ao substrato, antes do enchimento das sacolas. Utilizou-se o delineamento experimental em blocos inteiramente casualizados, em esquema fatorial 4x4, com quatro repetições e cinco plantas por parcela experimental. Foram realizadas avaliações aos 15; 30; 60 e 100 dias após a semeadura, sendo elas: emergência (%), número de folhas, comprimento da parte aérea e da raiz (cm), massa seca da parte aérea, da raiz e total (mg). Houve interação significativa dos fatores testados para o comprimento da parte aérea, aos sessenta e cem dias após a semeadura; efeito isolado do bokashi para todas as variáveis analisadas, exceto na emergência, comprimento da parte aérea e número de folhas aos trinta dias após a semeadura. O uso conjugado dos fertilizantes mostrou efeito positivo na precocidade e altura da planta, podendo ser recomendado na formulação de substratos para a produção de mudas de mamoeiro do grupo Solo.

Utilização de água residuária de suinocultura na produção de mudas de maracujazeiro-azedo cv Redondo Amarelo

O aproveitamento de água residuária de suinocultura, além de servir como fonte de nutrientes, constitui-se numa prática de reutilização da água, evitando a poluição de água e do solo. Com esse intuito, foi instalado e conduzido um experimento aproveitando a água residuária de suinocultura para o desenvolvimento de mudas de maracujazeiro-azedo visando a suprir a necessidade de fertilizantes comerciais. Foi utilizado o esquema fatorial 5 x 2, no delineamento de blocos casualizados, sendo os fatores: as concentrações de água residuária de suinocultura (0; 25; 50; 75 e 100%) e os tipos de substrato (comercial e a mistura de terra+areia, na proporção v/v de 2:1), com 4 repetições e sete plantas por parcela. Após 60 dias, foram avaliadas as seguintes características: comprimento da parte aérea e do sistema radicular (cm), número de folhas, área foliar (cm²), matéria seca da parte aérea e do sistema radicular (mg) e análise foliar e de fertilidade do substrato terra+areia. O melhor desenvolvimento das mudas de maracujazeiro-azedo ocorreu com a aplicação da água residuária de suinocultura na concentração de 100%. A utilização da água residuária supriu a demanda nutricional de mudas de maracujazeiro-azedo na fase inicial, sem o fornecimento de fertilizantes comerciais. A utilização de substratos mais porosos, como o Plantmax, favoreceu o desenvolvimento de mudas de maracujazeiro-azedo.

Parâmetros morfológicos de mudas de Sesbania virgata (Caz.) Pers e de Anadenanthera peregrina (L.) cultivadas em substrato fertilizado com composto de lixo urbano

Objetivou-se avaliar o efeito do composto de lixo urbano nos parâmetros morfológicos de mudas de sesbânia e de angico. Os substratos de cultivo tiveram as seguintes proporções de composto e de amostras de subsolo de Neossolo Quartzarênico ou de Latossolo Vermelho-Amarelo (%): 0:100; 20:80; 40:60; 60:40 e 80:20, sem a utilização de fertilização mineral. As sementes de sesbânia foram inoculadas com a estirpe recomendada BR 5401. Os parâmetros morfológicos das mudas de sesbânia e angico, suas relações e índice de qualidade de Dickson (IQD) foram determinados aos 56 e 120 dias após a semeadura, respectivamente para cada espécie. Os efeitos dos substratos nos parâmetros morfológicos das mudas de sesbânia e angico variaram de acordo com as proporções do substrato. Para o angico, a adição do composto proporcionou aumento na altura da parte aérea, razão entre massa seca de parte aérea por massa seca de raiz e IQD. Para sesbânia, a adição do composto de lixo ao substrato proporcionou aumento na altura da parte aérea, diâmetro do coleto, massa seca de raiz, da parte aérea e total, razão entre massa seca da parte aérea por massa seca de raiz, IQD e número de nódulos. A obtenção de máxima produção de matéria seca total, diâmetro do coleto e IQD foi de 57:43, sendo, portanto, esta a proporção composta de lixo:solo recomendada para a produção de mudas de sesbânia.

Variation Laws of Anthocyanin Content in Roots and Their Relationships with Major Economic Traits in Purple-Fleshed Sweetpotato [ Ipomoea batatas (L.) Lam

Variation laws of anthocyanin content in root during the development and among the varieties, and their relationships with major economic traits in purple-fleshed sweetpotato [ Ipomoea batatas (L.) Lam] were studied in the present article. The dynamics of 20 economic traits in 13 purple-fleshed sweetpotato varieties at 20, 40, 60, 80, 100, 120, and 140 d after their transplanting were investigated, and these traits included anthocyanin content in root, length of the longest vine, number of base branches, root number, dry matter contents in stem, foliage and root, fresh/dry weight of root, fresh/dry weight of stem, fresh/dry weight of foliage, fresh/dry weight of stem and foliage, fresh/dry weight of whole plant, and rations of photosynthate to root, stem, and foliage. The correlations between the variations of anthocyanin content and the other 19 economic traits among varieties and during the whole developing stages, and the correlations of daily increase of anthocyanin content with other 10 kinds of yields were analyzed. The results showed that: (1) During the whole development, the anthocyanin content had three variation types, i.e. a slow-increase type, a fluctuating-change type, and a deviousrising type, and had different responses to the growth of length of the longest vine, number of base branches, fresh/dry yield of root, and photosynthate allotments. (2) The anthocyanin contents among 13 varieties began to have significant difference after 20 d, and showed completed differentiation during 40–100 d, which had significantly negative correlationships with the number of base branches, fresh/dry yield of root, photosynthate allotment ratio to root, and had significant positive correlationships with dry matter content of root, length of the longest vine, fresh/dry yield of stem, dry yield of whole plant and photosynthate allotment ratio to foliage. (3) Because of the significantly negative correlation between daily increase of anthocyanin content and dry matter weight of root, the anthocyanin accumulation competed with dry matter accumulation for photosynthate in root, and the competitive relation was resolved in different ways in different purple-fleshed sweetpotato (PFSP) varieties. So, there had three variation types of anthocyanin content among PFSP varieties during their development, and had different correlations between these variations of anthocyanin content and the major economic traits.

Avaliação da especificidade de rizobactérias isoladas de diferentes espécies de Pinus sp.

Testou-se a especificidade das rizobactérias promotoras de crescimento em mudas de P. taeda L., P. oocarpa, P. elliottii Engelm. e P. caribaea var. hondurensis. Os isolados de rizobactérias UFV-AL9, UFV-AM5, UFV-AM2, UFV-F3, UFV-G2, UFV-G4, UFV-Z1, UFV-F6 e UFV-X2 foram inoculados por meio da aplicação de inóculo de rizobactérias em substrato de produção de mudas. Aos 150 dias de semeadura, avaliou-se o peso de matéria seca de raízes e da parte aérea das mudas, bem como o índice de qualidade de Dickson. Foram constatadas interações significativas dos isolados e das diferentes espécies de pinus. Os incrementos da biomassa da parte aérea e do sistema radicular variaram conforme o isolado e a espécie de pinus, porém, de modo geral, foram observados maiores médias das mudas de P. taeda. As mudas de P. taeda, inoculadas com os isolados UFV-Z1 e UFV-AM5, apresentaram ganhos significativos de biomassa da parte aérea, do sistema radicular e do índice de qualidade de Dickson, em relação à testemunha. Nas mudas de P. elliottii, observou-se também aumento significativo da biomassa da parte aérea, quando inoculadas com o isolado UFV-AM5 e do sistema radicular com os isolados UFV-X2, UFV-G2 e UFV-AM5. O isolado UFV-AM5 não se mostrou específico para essas variáveis, nas duas das quatro espécies estudadas (P. taeda e P. elliottii).