Maximum Root Dry Weight Research Articles

Standardization of size of cutting and IBA concentrations on the multiplication of underutilized leafy vegetables of Assam

An experiment unfolded at the Experimental Farm in the Department of Horticulture, AAU, Jorhat during 2021-22 to analyse the effect of different concentrations of IBA viz., H1: distilled water, H2: 25 ppm, H3: 50 ppm and H4: 75 ppm on three different cutting sizes (N1: 1 node, N2: 3 nodes, N3: 5 nodes) across three underutilized leafy vegetables (Brahmi, Matikanduri, Madhusoleng). In nursery, the experiment (I) was put out in Factorial Randomised Block Design (FRBD) from which the best and the poorest treatment of each crop were planted in the main field for further studies on their growth. In the main field, the experiment (II) was laid out in Randomized Block Design with four replications. The interaction between cutting size and IBA concentration spotlighted N3H4 as the pinnacle treatment in Brahmi displaying superior rooting percentage, longest root length, root diameter, highest root fresh and dry weights, highest root number, and hastening new leaf appearance. In Matikanduri, N3H4 excelled in rooting percentage, root length, root diameter, fresh weight, and root number, whereas N3H3 caused the maximum root dry weight and quickest new leaf emergence. Madhusoleng exhibited optimal results with N3H4, showcasing the highest rooting percentage, longest root length, root diameter, root fresh and dry weights, root number, and minimum time to new leaf appearance. In the main field, Brahmi-survival percentage (99.50%), plant height (21 cm), plant spread (29.25 cm), number of branches (3.75), leaf number (21.25), Matikanduri- survival percentage (98.75%), plant height (40.45 cm), plant spread (68.95 cm), number of branches (38.25), leaf number (330.50), Madhusoleng- survival percentage (98.50%), plant height (82.00 cm), plant spread (102.25 cm), number of branches (31.00), leaf number (378.75) were found to be best in the same treatment combination of N3H4 with maximum BC ratio of 3.31, 4.46, and 5.80, respectively.

Salt stress effects on growth, physiology, and ionic concentrations in hydroponically grown barley genotypes

Soil salinity is a major abiotic stress that severely affects crop production in different regions of the globe. Barley is an essential cereal crop and there is a significant genetic variation among barley varieties for tolerance towards salt stress. Understanding of salinity tolerance mechanisms assists in developing salt tolerant barley varieties in a hydroponics experiment. There were twelve barley varieties and two NaCl stress levels (Control, 100 and 200 mM) in this study. The nursery of barley was seeded in sand and at two-leaf stage; plants were transplanted into hydroponic tubs. The plants were grown under salt stress for 65 days and data regarding several morpho-physiological parameters were collected. The statistical analysis of the collected data was implemented by using completely randomized design (CRD) with factorial arrangement. Exposure to NaCl stress significantly reduced shoot and root growth and relative leaf water contents (RLWC), while increasing Na+ concentration, with B-9006 showing the highest root dry weight (0.39 g) and YSM1 recorded the lowest root dry weight (0.10 g) under 100 mM NaCl. The maximum (232 ppm) Na+ concentration in leaf sap was observed in variety B-15011 (70 % from control) and minimum was observed in B-15018. Maximum K+ mM concentration in leaf sap was found as 72 % in Aia-03 and minimum was observed as 50 % in B-15035. At stress level of 200 mM, highest shoot dry weight (2.52 g) was observed in ZP2 (73 % decreased from control) while minimum shoot dry weight (0.19 g) (96 % decrease from control) was recorded in Franklin genotype. Maximum root dry weight (0.24 g) was observed in B-9006 genotype while minimum root dry weight (0.04 g) was recorded in Gairdner. Maximum K+/Na+ ratio (1.20) was recorded in B-15018 and minimum (0.14) was seen in B-15035. Therefore, based on our results, barley genotypes can be classified into salt-tolerant (B-9006, B-15018, Yerong, Aia-03), salt-sensitive (Gairdner, Franklin, B-15035, B-05011), and moderately tolerant groups at both 100 and 200 mM NaCl levels.

Improvement of Seed Germination and Seedling Growth of Faba Bean (Vicia Faba L.) through Seed Priming

In a lab experiment using seed priming, the faba bean (Vicia faba L.) seed germination and seedling development were studied. Twenty different priming techniques were utilized in the study, each comprising varying concentrations of NaOCI, CaCl2, KNO3, Manitol, PEG, KCL, H2O and a control group that received no priming. Four replications of a completely randomized design (CRD) were used in the experiment. Among the three priming treatments, there were substantial differences in the seedling growth metrics and germination rate. When 500 ppm NaOCl was used as a treatment, the highest seed germination percentage (96%) was attained. Although 100 ppm PEG had the greatest germination index (42.92), 10000 ppm NaOCl had the quickest mean germination time (8.27). Additionally, at a concentration of 1500 ppm NaOCl, the greatest seedling vigor index (29.79) and maximum germination coefficient (12.28) were likewise obtained. With H2O treatment, the maximum shoot length (21.09 cm) was observed for seedling growth parameters. The largest root length was produced by a 10000 ppm KNO3 treatment (11.19 cm). With 20000 ppm KNO3, the maximum root dry weight was achieved (88.50 mg), whereas H2O produced the highest shoot dry weight (51.0 mg). Additionally, it was discovered that a treatment with 10000 ppm KNO3 had the best root-shoot ratio (0.72). The research thus supports the possible use of seed priming as a method to improve faba bean seed germination and seedling growth. NaOCl and KNO3 seemed to work best for faba bean seed germination and seedling growth.

Vermicompost as an alternative substrate to peat moss for strawberry (Fragaria ananassa) in soilles culture

BackgroundConsecutive droughts and quantitative and qualitative reduction of surface and underground water resources have caused an increase in greenhouse and hydroponic cultivation for most garden crops, including strawberries, in Iran. On the other hand, most of the inputs of greenhouse crops in Iran are imported. To possibility of replacing vermicompost with peat moss under hydroponic cultivation, an experiment was done in a split plot based on randomized complete blocks design in three replications in Isfahan (Iran) Agricultural and Natural Resources Research Center in 2019. The main treatment was substrate at four levels included different levels of vermicompost (30 and 50%) and peat moss (30 and 50%) in combination with perlite and sub-treatment were Selva and Camarosa cultivars.ResultsThe results showed that Camarosa cultivar and Selva cultivar in (perlite/ peat moss 50:50) and Selva cultivar in (perlite / vermicompost 70:30) had maximum yield.Leaf number and chlorophyll index were maximum in Camarosa cultivar in peat moss substrates. Strawberry cultivars had the highest root fresh weight, the content of vitamin C and total soluble solids (TSS) in substrates containing vermicompost. Camarosa cultivar in (perlite / peat moss50:50) and Selva cultivar in (perlite /vermicompost 50:50) had maximum root dry weight. Also, the highest number of inflorescences was related to substrates containing peat moss and (perlite /vermicompost 70:30). Maximum amount of fresh and dry weight of shoots were observed in (perlite/ peat moss70:30). Selva cultivar had more inflorescences (16.5%) than Camarosa cultivar and Camarosa cultivar produced more fresh and dry weight of shoots (16.5%, 23.01%) than Selva cultivar.ConclusionExpriment results highlighted the importance of considering both main and sub-treatments in agricultural research, as they interacted to influence various growth and yield parameters. 50% vermicompost treatment combined with perlite had a positive impact on plant growth and in quality index such as vitamin C content and TSS was highest. while the choice of cultivar affected different aspects of plant development. Selva cultivar was known to be more tolerant to salinity caused by vermicompost. Vermicompost is local and more economical, also salt resistant cultivars are recommended in a controlled (30%) amount of vermicompost.

Effects of silicon nanoparticles and conventional Si amendments on growth and nutrient accumulation by maize (Zea mays L.) grown in saline-sodic soil

Salinity is one of the major abiotic stresses in arid and semiarid climates which threatens the food security of the world. Present study had been designed to assess the efficacy of different abiogenic sources of silicon (Si) to mitigate the salinity stress on maize crop grown on salt-affected soil. Abiogenic sources of Si including silicic acid (SA), sodium silicate (Na–Si), potassium silicate (K–Si), and nanoparticles of silicon (NPs-Si) were applied in saline-sodic soil. Two consecutive maize crops with different seasons were harvested to evaluate the growth response of maize under salinity stress. Post-harvest soil analysis showed a significant decrease in soil electrical conductivity of soil paste extract (ECe) (−23.0%), sodium adsorption ratio (SAR) (−47.7%) and pH of soil saturated paste (pHs) (−9.5%) by comparing with salt-affected control. Results revealed that the maximum root dry weight was recorded in maize1 by the application of NPs-Si (149.3%) and maize2 (88.6%) over control. The maximum shoot dry weight was observed by the application of NPs-Si in maize1 (42.0%) and maize2 (7.4%) by comparing with control treatment. The physiological parameters like chlorophyll contents (52.5%), photosynthetic rate (84.6%), transpiration (100.2%), stomatal conductance (50.5%), and internal CO2 concentration (61.6%) were increased by NPs-Si in the maize1 crop when compared with the control treatment. The application of an abiogenic source (NPs-Si) of Si significantly increased the concentration of phosphorus (P) in roots (223.4%), shoots (22.3%), and cobs (130.3%) of the first maize crop. The current study concluded that the application of NPs-Si and K–Si improved the plant growth by increasing the availability of nutrients like P and potassium (K), physiological attributes, and by reducing the salts stress and cationic ratios in maize after maize crop rotation..

Identification of Cutting Types for the Successful Regeneration of Two Plum (Prunus salicina Lindl) Rootstock Varieties

This study was initiated to identify the best type of cutting for the successful regeneration of two plum rootstock varieties. Three stem cutting types (hardwood, semi-hardwood and softwood) were collected from two plum rootstock varieties (Mariana GF 8-1 and Myrobalan 29C) and have been evaluated for root, shoot and leaf traits. The result revealed that semi-hardwood cuttings of Myrobalan 29C received the earliest (15 days) sprouting while the number of shoots (3.13-3.98) and length (13.63 cm) were higher in Mariana GF 8-1. The highest sprouting (93.33-96.67%) were recorded from both hardwood and semi-hardwood cuttings of Mariana GF 8-1. Hardwood and softwood cuttings of Mariana GF 8-1 had also obtained better shoot fresh (12.89-13.26 g) and dry weight (2.67-3.33 g), respectively, while leaf number was higher (43.07) in the hardwood cuttings. The widest (2.34-2.51 cm) and longest (4.80-4.81) leaves were obtained from Myrobalan 29C cuttings of all types while the maximum number of roots (37.67), root grade (7.63) and root length (12.62 cm) were recorded from semi-hardwood and hardwood Myrobalan 29C cuttings, consecutively. The highest rooting percentage (100.00%) was observed in the semi-hardwood Mariana GF 8-1 cuttings. Hardwood and softwood Myrobalan 29C plus hardwood and semi-hardwood Mariana GF 8-1 cuttings had received statistically similar and highest roots fresh weights (14.11-14.33 g). However, hardwood Mariana GF 8-1 cuttings alone had recorded the maximum root dry weight (4.00 g). Overall, cutting type particularly hardwood cutting could be considered for successful regeneration of both varieties though Mariana GF 8-1 had succeeded Myrobalan 29C in most of the parameters. Key words :Cutting, leaf, plum, root, rootstocks, shoot DOI: 10.7176/ALST/85-04 Publication date: January 31 st 2021

An Investigation of a Root Zone Heating System and Its Effects on the Morphology of Winter-Grown Green Peppers

The winter season in Nanjing is from December to February, with extremely low temperature and high humidity due to seasonal snowfall. During these extreme cold climatic conditions, plants have to survive severe heat stress conditions, even if they are being kept in greenhouses. The objective of this study was to investigate a heating system that can provide heat directly to the root zone instead of heating the entire greenhouse, which is a viable option to reduce energy consumption. Root zone heating could be an effective alternative for the sustainable development of plants during the winter. A novel type of root zone heating system was applied to evaluate the energy consumption during different greenhouse ambient temperature conditions, the effects of root zone heating systems on pepper plant morphology, and heat transfer rates to plant canopy in the greenhouse. The temperature treatments in root zone heating system were T-15, T-20, T-25, T-30, and a control treatment (TC) at 15 °C, 20 °C, 25 °C, and 30 °C, respectively, while TC received no heat. A simulation study was carried out to validate the root zone temperature. The results of the current investigation revealed that energy consumption has an inverse relationship to the ambient temperature of the greenhouse, while temperature gradients to the plant canopy observed from the lower to the upper part of the plant and the upper canopy experienced less temperature fluctuation as compared to the lower part of the plant. The results also showed that treatment T-20 had the maximum in terms of the leaf dry weight, stem diameter, and the number of leaves, while T-25 showed the maximum root dry weight and stem dry weight; T-30 and T-15 had minimum dry weights of plant segments among all treatments. Control treatment (TC) showed a minimum dry mass of plant. The root zone heating with optimal root zone temperature was found to be a viable and adaptable option as this leads to improved energy consumption patterns for the sustainable growth and development of plants in greenhouses during extremely low temperatures.

Root growth, nutrient uptake and use efficiency by roots of tropical legume cover crops as influenced by phosphorus fertilization

ABSTRACTThe root is an important organ which supplies water and nutrients to growing plants. Data related to root growth and nutrient uptake by tropical legume cover crops are limited. The objective of this study was to evaluate root growth of tropical legume cover crops and nutrient uptake and use efficiency under different phosphorus (P) levels. The P levels used were 0 (low), 100 (medium) and 200 (high) mg kg−1 of soil and 5 cover crops were evaluated. Root dry weight, maximum root length, specific root length were significantly influenced by P and cover crop treatments. Maximum values of these root growth parameters were achieved with the addition of 100 mg P kg−1 soil. The P X cover crops interaction for all the macro and micronutrients, except manganese (Mn) was significant, indicating variation in uptake pattern of these nutrients by cover crops with the variation in P rates. Overall, uptake pattern of macronutrients was in the order of nitrogen>calcium>potassium>magnesium>phosphorus (N > Ca > K > Mg > P) and micronutrient uptake pattern was in the order of iron>manganese>zinc>copper (Fe > Mn > Zn > Cu). Cover crops which produced maximum root dry weight also accumulated higher amount of nutrients, including N compared to cover crops which produced lower root dry weight. Higher uptake of N compared to other nutrients by cover crops indicated that use of cover crops in the cropping systems can reduce loss of nitrate (NO3−) from soil-plant systems. Increase in root length and root dry weight with the addition of P can improve nutrient uptake from the soil and less loss of macro and micronutrients from the soil-plant systems.

Potassium Requirements of Lowland Rice

Rice is a staple food for about 50 percent of the world’s population. Potassium (K) is absorbed in large amounts by rice plants and adequate amounts of this element are fundamental to improve productivity and maintain sustainability of the cropping systems. A greenhouse experiment was conducted to determine the adequate rate of K for lowland rice grown on a Brazilian Inceptisol. The K rates used were 0, 50, 100, 200, 400, and 600 mg K kg−1 soil. Most of the growth, yield, and yield components were significantly and quadratically increased with increasing K levels. Based on a quadratic equation, maximum grain yield was obtained with the addition of 371 mg K kg−1 soil. Maximum plant height and shoot dry weight were obtained at 414 and 398 mg K kg−1 soil, respectively. Root growth (maximum length and dry weight) was also significantly increased in a quadratic fashion with the increasing K rate in the growth medium. Maximum root length was achieved at 58 mg K kg−1 whereas maximum root dry weight was obtained with the addition of 394 mg K kg−1 soil. Plant height, shoot dry weight, 1000-grain weight, root length, and root dry weight were significantly associated with grain yield. Hence, manipulation of these growth and yield components with the addition of K fertilizer can improve yield of lowland rice in varzea soils of central part of Brazil. Potassium uptake increased significantly in a quadratic fashion with increasing K rate. However, K-use efficiency (mg grain per mg K applied) decreased significantly with increasing K rate in a quadratic fashion. Maximum grain yield was obtained with 117 mg kg−1 Mehlich 1–extractable K, base saturation of 53 percent, Mg saturation of 9 percent, K saturation of 2 percent, and Ca/Mg ratio of 4.

Molybdenum Requirements of Dry Bean with and without Liming

Molybdenum (Mo) is an essential micronutrient for crop plants, and its deficiency has been reported in many parts of the world. Two greenhouse experiments were conducted with the objective to determine Mo requirements of dry bean (Phaseolus vulgaris L.) grown on a Brazilian Oxisol with and without liming. The Mo treatments were 0, 5, 10, 15, and 20 mg kg−1. In one experiment dolomitic lime was added at the rate of 2.5 g per kg of soil before the application of Mo treatments and incubated 5 weeks before sowing. In other experiments, Mo treatments were same as the lime-added experiment but no lime was added. Most of the growth, yield, and yield components were significantly increased with the addition of Mo in both the experiment. Growth, yield, and yield components were increased in a quadratic fashion when Mo was applied in the range of 0 to 20 mg kg−1. Maximum shoot dry weight was obtained with the addition of 17 mg Mo kg−1 in the experiment with Mo rates without lime and 9.69 mg Mo kg−1 in the experiment of Mo rates with lime application. Maximum seed yield was obtained with the application of 10.48 mg Mo kg−1 in the experiment that did not receive lime along with Mo treatments and 10.28 mg Mo kg−1 in the experiment that received lime along with Mo treatments. Similarly, the maximum number of pods per plant was obtained with the addition of 9.33 mg Mo kg−1 in the experiment that did not receive lime and 8.83 mg Mo kg−1 in the experiment that did receive lime. Maximum root length was obtained with the addition of 12.38 Mo kg−1 in the experiment that did not receive lime and 9.75 mg Mo kg−1 in the experiment that received lime. Maximum root dry weight was obtained with the addition of 11.67 mg Mo kg−1 in the experiment that did not receive lime and 9.28 mg Mo in the experiment that received lime. Soil properties determined after harvest of dry bean plants were not influenced significantly with the addition of Mo in the Oxisol under investigation.

Root Growth, Nutrient Uptake, and Nutrient-Use Efficiency by Roots of Tropical Legume Cover Crops as Influenced by Phosphorus Fertilization

Roots are important organs that supply water and nutrients to growing plants. Data related to root growth and nutrient uptake by tropical legume cover crops are limited. The objective of this study was to evaluate root growth of tropical legume cover crops and nutrient uptake and use efficiency under different phosphorus (P) levels. The P levels used were 0 (low), 100 (medium), and 200 (high) mg kg−1 of soil, and five cover crops were evaluated. Root dry weight, maximum root length, and specific root length were significantly influenced by P and cover crop treatments. Maximum values of these root growth parameters were achieved with the addition of 100 mg P kg−1 soil. The P × cover crops interactions for all the macro- and micronutrients, except manganese (Mn), were significant, indicating variation in uptake pattern of these nutrients by cover crops with the variation in P rates. Overall, uptake pattern of macronutrients was in the order of nitrogen (N) > calcium (Ca) > potassium (K) > magnesium (Mg) > P and micronutrient uptake pattern was in the order of iron (Fe) > Mn > zinc (Zn) > copper (Cu). Cover crops which produced maximum root dry weight also accumulated greater amount of nutrients, including N, compared to cover crops, which produced lower root dry weight. Greater uptake of N compared to other nutrients by cover crops indicated that use of cover crops in the cropping systems could reduce loss of nitrate (NO3 −) from soil–plant systems. Increase in root length and root dry weight with the addition of P can improve nutrient uptake from the soil and lessen loss of macro- and micronutrients from the soil–plant systems.

Evaluation of Tropical Legume Cover Crops for Copper Use Efficiency

Cover crops are important components of cropping systems due to their role in improving soil quality. Lack of adequate levels of soil micronutrients prevents the success of cover crops in highly weathered tropical soils. A greenhouse experiment was conducted with the objective to evaluate copper use efficiency of nine tropical legume cover crops. The copper levels used were 0, 5, 10 and 20 mg Cu kg-1 of soil. Shoot dry weight, maximum root length and root dry weight significantly increased in a quadratic fashion with increasing soil Cu levels in the range of 0 to 20 mg kg-1 soil. Cu x cover crops interactions for shoot dry weight, root dry weight, maximum root length and contribution of root to the total dry weight were significant, indicating different responses of cover crops with the variation in soil Cu levels. Overall, maximum shoot dry weight was obtained with the application of 13 mg Cu kg-1. Similarly, maximum root dry weight and maximum root length were obtained with the application of 12 and 14 mg Cu kg-1 of soil. Root dry weight and maximum root length were significantly and positively related to shoot dry weight, indicating that a vigorous root system is important for improving productivity of cover crops grown on Brazilian Oxisols, especially where deficiency of micronutrients such as Cu exists. The Cu concentration in the plant tissue decreased in a quadratic fashion whereas, Cu uptake increased with increasing Cu application rate from 0 to 20 mg kg-1 soil. There was a significant variation observed in Cu use efficiency among cover crop species. Increasing applied Cu levels significantly increased soil pH and Mehlich 1 extractable soil Cu, Zn, Mn and Fe concentrations in the soil solution.

Zinc Requirements of Tropical Legume Cover Crops

Tropical soils are deficient in essential plant nutrients, including zinc (Zn). Using cover crops in cropping systems is an important option to improve soil fertility for sustainable crop production. However, success of cover crops in highly weathered tropical infertile acid soils is greatly influenced by adequate levels of available soil micronutrients. A greenhouse experiment was conducted to evaluate the Zn requirements of ten major tropical legume cover crops. The Zn levels used were 0, 10, 20 and 40 mg·kg-1 soil. Overall, shoot and root dry weight and maximum root length increased significantly in a quadratic fashion with increasing Zn rates in the range of 0 to 40 mg·kg-1. The Zn × cover crops interactions for shoot and root dry weight, maximum root length, Zn concentration (content per unit dry weight), Zn uptake (concentration × dry weight) and Zn use efficiency (dry weight per unit Zn uptake) were significant, indicating variation in these traits with the change in soil Zn levels. Collectively, maximum shoot dry weight was achieved with the application of 22 mg Zn·kg-1 of soil. Similarly, maximum root dry weight and root length were obtained with the addition of 22 and 17 mg Zn·kg-1 soil, respectively. Overall, Zn concentration and Zn uptake were significantly increased in a quadratic manner with the increase in the soil Zn levels in the range of 0 to 40 mg·kg-1. However, Zn use efficiency (dry weight per unit Zn uptake) decreased in a quadratic fashion with the increasing soil Zn levels from 0 to 40 mg·kg-1. Jack bean, black velvet bean, pueraria, and gray velvet bean with high Zn use efficiency appear to be suitable cover crops for low Zn soils.

NOTA TECNICA: RESPOSTA DA INOCULAÇÃO DE FUNGOS MICORRÍZICOS E RIZÓBIO NO CRESCIMENTO INICIAL DE Acacia mangium EM SOLO DE MINERAÇÃO NO ESTADO DE GOIÁS

Este estudo teve como objetivo avaliar o crescimento de Acacia mangium em solo degradado por mineração no Sudoeste do estado de Goiás. As sementes de A. mangium foram germinadas em câmara de germinação a 26 ºC, por três dias. As mudas foram inoculadas com fungos micorrízicos arbusculares (FMAs) isolados da rizosfera de milho e/ou rizóbio no momento do plantio. Os tratamentos rizóbio, FMAs, FMAs+rizóbio e controle foram avaliados em casa de vegetação por 120 dias. Foi observado aumento no peso seco de caules e folhas entre os tratamentos inoculados com FMAs e/ou rizóbio, sendo o tratamento com rizóbio superior aos demais. O maior peso seco de raiz foi observado no tratamento FMAs/rizóbio, devido à densa formação de raízes laterais. Não houve diferença significativa de comprimento de raiz entre os tratamentos rizóbio, FMAs e FMAs/rizóbio. A colonização micorrízica influenciou a formação de nódulos por rizóbio nativo no solo no tratamento com FMAs, não havendo diferença significativa entre os tratamentos FMAs e rizóbio. A inoculação com FMAs e rizóbio pode ser uma alternativa viável para o desenvolvimento de programas de recuperação de áreas degradadas por mineração, devido ao melhor desenvolvimento do sistema radicular e foliar.

Day/Night Temperatures Influence Growth and Photosynthesis During Containerized Production of Selected Species of Helleborus (Hellebores)

Abstract Containerized seedlings of Helleborus foetidus L. (stinking hellebore), H. niger L. (Christmas rose), and H. ×hybridus L. (Lenten rose) were grown under long-day conditions in controlled-environment chambers for 95 days with 9-hr days of 14, 18, 22, 26, or 30C (57, 64, 72, 79, or 86F) in factorial combination with 15-hr nights of 10, 14, 18, 22, or 26C (50, 57, 64, 72, or 79F). Long-day conditions were provided by a 3-hr night interruption. Growth of each species responded differently to day and night temperatures. Calculated maximum root, top, and total dry weight, and leaf area of H. foetidus occurred with days/nights of 20/15, 18/13, 19/14, and 18/15C (68/59, 65/55, 66/57, and 65/59F), respectively. While night temperature (NT) had no effect on root:top ratio [RTR (root dry weight ÷ top dry weight)], RTR was greatest (0.65) with days of 22C (72F). Helleborus niger had calculated maximum root dry weight and total dry weight with days of 14C (57F) and nights of 16 and 13C (60 and 55F), respectively. Top growth of H. niger decreased linearly as NTs increased for days of 14 or 22C (57 or 72F). Day temperatures (DTs) had no effect on RTR, whereas RTR responded quadratically as NT increased with a calculated maximum RTR at nights of 19C (66F). Leaf area was maximized at days/nights of 14/10C (57/50F). At days of 22 or 26C (72 or 79F), top growth of H. ×hybridus responded quadratically as NT increased with maxima occurring at nights of 18 or 17C (64 or 63F). Root dry weight responded quadratically at days of 14, 22, or 26C (57, 72, or 79F) and calculated maxima occurred with nights of 18C (64F). At days of 22 or 26C (72 or 79F), there were quadratic responses in total dry weight with calculated maximum growth of H. ×hybridus at nights of 18 or 17C (64 or 63F), respectively. For days of 14, 22, or 30C (57, 72, or 86F), there were quadratic responses in RTR with greatest RTR calculated at nights of 15, 18, or 16C (59, 64, or 60F), respectively. There were quadratic responses at days of 22 or 26C (72 or 79F) for leaf area with calculated maxima at nights of 18 or 17C (64 or 63F), respectively. As DTs increased from 14 to 30C (57 to 86F) net CO2 assimilation (PN) of H. ×hybridus also increased linearly whereas increased NTs had no effect on PN. In contrast, stomatal conductance was not impacted by DT or NT.

Transporte de boro no solo e sua absorção por eucalipto

O mecanismo e a magnitude do transporte de B até as raízes das plantas dependem da umidade e do teor do nutriente no solo. As contribuições do fluxo de massa e da difusão para o transporte de B até as raízes de eucalipto foram avaliadas em resposta ao potencial de água do solo e às doses do nutriente. No ensaio, foram utilizados dois potenciais de água do solo (-10 e -40 kPa) e seis doses de B (0, 0,5, 1, 2, 3 e 5 mg dm-3 de B). As plantas foram cultivadas em vasos com capacidade de 2,5 dm³ em casa de vegetação. O controle do potencial da água do solo foi efetuado pelo uso de um tensiômetro por vaso, e o ajuste por acréscimo de água destilada. A máxima produção de matéria seca de raízes foi obtida nas doses correspondentes a 0,98 e 2,38 mg dm-3 de B nos potenciais de água de -10 e -40 kPa, respectivamente. A máxima produção de matéria seca de parte aérea foi obtida nas doses correspondentes a 0,96 e 1,82 mg dm-3 de B nos potenciais de água de -10 e -40 kPa, respectivamente. Foram observadas relações positivas e altamente significativas (p < 0,01) entre as doses de B aplicadas, o B extraível do solo, o B na solução do solo e o conteúdo de B na planta, para ambos os potenciais de água. O fluxo de massa foi o mecanismo predominante no transporte de B, chegando a suprir 100 % das necessidades das plantas nas doses mais elevadas do nutriente. O fluxo difusivo foi o mecanismo complementar de maior importância relativa no solo com baixo teor de B e com déficit hídrico.

Morphological attributes of oriental spruce [ Picea orientalis (L.) Link.] seedlings grown in peat-based media amended with natural zeolite

This study was designed to investigate the influence of growth media consisting of different components on the morphological attributes of oriental spruce seedlings. Eighteen different combinations of Barma peat (BP), tea residue compost (CTR), fine pumice (FP), coarse pumice (CP), perlite (P) and zeolite (Z) were prepared as growth media.The growth medium components did not significantly affect the shoot height (SH), root collar diameter (RCD), shoot:root ratio or dry root percentage (DRP) of 2-year-old seedlings. However, the root dry weight (RDW) and shoot dry weight (SDW) showed significant differences between the different growth media. The maximum SDW (3.244 g) was determined for a mixture of BP (0.5) + CTR (0.2) + CP (0.2) + Z (0.1), while a mixture of BP (0.6) + P (0.2) + Z (0.2) resulted in minimum SDW (1.593 g). In addition, the maximum RDW (1.824 g) was determined for the BP (0.5) + CTR (0.2) + CP (0.2) + Z (0.1) medium, while the BP (0.6) + CP (0.2) + Z (0.2) medium resulted in the lowest RDW (1.013 g). The addition of zeolite to the growth media increased the SDW and RDW of oriental spruce seedlings, so natural zeolite could be used as a substrate to replace pumice and perlite in nurseries in Turkey. Since Turkey has 45.8 billion tonnes of zeolite, its use in nurseries could reduce the costs significantly.

Adubação orgânica na produção de pimentão

Com o objetivo de avaliar os efeitos da adubação orgânica na produção de pimentão (Capsicum annuum L.), cultivar Nacional AG 506, foram conduzidos dois experimentos: um em casa-de-vegetação e outro a campo na área experimental do Centro Agropecuário da UFES em Alegre (ES), no período de março a outubro de 1994. Em casa-de-vegetação foram avaliados seis níveis de vermicomposto (0, 200, 400, 600, 800 e 1000 g por vaso) associados à ausência e presença de adubação química. O delineamento experimental utilizado foi o inteiramente casualizado com cinco repetições de uma planta por vaso. Após 45 dias foram avaliados o peso da matéria seca da parte aérea e da raiz. No campo, 12 t/ha de vermicomposto (600 g/cova) foram comparados com 20 t/ha (1000 g/cova) de esterco de curral, na ausência e presença de adubação química. Os tratamentos foram distribuídos em blocos ao acaso com quatro repetições de dez plantas por parcela. Por meio de regressão linear, determinou-se que em casa-de-vegetação, a máxima produção de matéria seca da parte aérea foi obtida com a aplicação de 561,9 g/vaso de vermicomposto e das raízes com 323,1 g/vaso, ocorrendo pequenos decréscimos em doses mais elevadas. No experimento de campo a adubação orgânica aumentou a produção em 7,0 t/ha em relação à testemunha adubada apenas com adubo químico. Não houve diferenças significativas entre as fontes de matéria orgânica (vermicomposto e esterco de curral).

Effects of Soil Calcium and pH on Seed Germination and Subsequent Growth of Large Crabgrass (Digitaria sanguinalis)

Large crabgrass is a problem weed in horticultural crops, particularly in turfgrass in the southeastern United States. If growth of large crabgrass could be suppressed via soil pH or calcium levels, control of this weed in turfgrass might be improved while minimizing herbicide usage. To determine the effect of soil calcium and pH on germination and growth of large crabgrass, seeds were sown in a loamy sand soil amended with calcium carbonate (CaCO3) or magnesium carbonate (MgCO3) that established a range of soil pH from 4.8 to 7.8. Seeds were also sown in soil amended similarly with calcium sulfate (CaSO4), which does not affect pH, that established a range of exchangeable Ca levels corresponding to the Ca range in CaCO3from pH 4.8 to 7.8. Seed germination of large crabgrass was unaffected by pH when soil was amended with CaCO3, whereas seed germination decreased with increasing pH when soil was amended with MgCO3. Crabgrass germination was not affected by Ca (CaSO4) independent of pH changes. Increasing soil pH reduced shoot and root dry weights of seedlings regardless of material used to raise pH. Maximum shoot dry weights occurred at pH 4.8 in the unamended soil, whereas maximum root dry weights occurred at ranges from pH 5.8 to 6.3 for CaCO3and pH 5.3 to 5.8 for MgCO3. Shoot and root dry weights were not affected by Ca when soil was amended with CaSO4. By raising soil pH levels, the growth of large crabgrass and its ability to compete with turfgrass may be reduced. Raising exchangeable Ca does not appear to be an effective management tool for control of this weed species.

Differences between Location in Root System of Potato Plants

Differences between locations in potato root system were studied with four varieties. Climatic conditions in two locations were almost same, though soil types were different: Soil of Sapporo and Shimamatsu were alluvial clay loam and volcanic ash sandy loam, respectively. Root dry weight of surface soil (depth to 30 cm), leaf area and tuber dry weight were measured biweekly during the growing season. Growth rate, duration of increase, maximum value and duration of root DW and LAI were calculated from quadratic regression curves fitted to raw data. Maximum values in root DW and LAI were greater in Sapporo than in Shimamatsu. Two values showed highly significant correlation (r=0.951). Diffcrences were also found in morphological characteristics of root and shoot. Root diameter, stem diameter and stem length were significantly greater in Sapporo. Number of root per stem, however, were greater in Shimamatsu. Differences in maximum root dry weight between locations were based on root growth rate in early varieties, and on root growth rate and duration of root increase in late varieties. On the other hand, differences in maximum LAI were attributable not to growth rate but to duration of leaf increase which was longer than duration of root increase. Greater maximum root dry weight in Sapporo delayed leaf senescence, and root dry weight duration during tuber bulking period was coerrelated with leaf area duration. Greater root dry weight duration and leaf area duration in Sapporo did not increase tuber bulking rate, but prolonged duration of tuber bulking and increased tuber yield. If root system increases rapidly or longer, then leaf growth also continues longer, thus leaf senescence might be delayed. It should result in long maintenance of tuber bulking and increase of tuber yield.