crops, including blackberry. The objective of the present study was to assess the impact of cultivar and weed management strategies on the accumulation and loss of plant biomass and nutrients during the first 3 years of establishment when using organic
Renee H. Harkins, Bernadine C. Strik, and David R. Bryla
Emily K. Dixon, Bernadine C. Strik, and David R. Bryla
al., 1999 ), while both stored N and new fertilizer N are allocated to floricane growth and fruit production ( Mohadjer et al., 2001 ). Blackberry has relatively low accumulation of biomass and N compared with other perennial crops due to the low
Christopher J. Currey and Roberto G. Lopez
to increasing the DLI during propagation ( Currey et al., 2012 ; Hutchinson et al., 2012 ; Lopez and Runkle, 2008 ). However, the mechanisms by which cuttings adapt biomass allocation patterns, gas exchange, and starch accumulation in response to
Mark G. Lefsrud, Dean A. Kopsell, Robert M. Augé, and A.J. Both
Consumption of fruit and vegetable crops rich in lutein and β-carotene carotenoids is associated with reduced risk of cancers and aging eye diseases. Kale (Brassica oleracea L. var. acephala D.C.) ranks highest for lutein concentrations and is an excellent source of dietary carotenoids. Kale plants were grown under varied photoperiods to determine changes in the accumulation of fresh and dry biomass, chlorophyll a and b, and lutein and β-carotene carotenoids. The plants were cultured in a controlled environment using nutrient solutions under photoperiod treatments of 6, 12, 16, or 24 hours (continuous). Fresh and dry mass production increased linearly as photoperiod increased, reaching a maximum under the 24-hour photoperiod. Maximum accumulation of lutein, β-carotene, and chlorophyll b occurred under the 24-h photoperiod at 13.5, 10.4, and 58.6 mg/100 g fresh mass, respectively. However, maximum chlorophyll a (235.1 mg/100 g fresh mass) occurred under the 12-hour photoperiod. When β-carotene and lutein were measured on a dry mass basis, the maximum accumulation was shifted to the 16-hour photoperiod. An increase in photoperiod resulted in increased pigment accumulation, but maximum concentrations of pigments were not correlated with maximum biomass production.
Sandra R. Menasha* and Milton E. Tignor
Sweet corn (Zea mays L.) is difficult to transplant due to poor root regeneration. Despite reduced yields, growers are transplanting sweet corn to hasten maturity time to target profitable early markets in the Northeast. Researchers have ascribed the negative impacts on yield to restricted rooting volume. Therefore, the impacts plug cell volume had on sweet corn transplant root architecture and biomass accumulation were investigated. `Temptation' sweet corn was sown in volumes of 15, 19, 14, and 29 mL correlating to transplant plug trays with plug counts of 200, 162, 128, and 72 plugs per tray. Plug cells were exposed to three substrate environments; a dairy manure based organic compost media, a commercial soil-less germination mix, and the soil-less media supplemented 2X with 200 ppm soluble 3-3-3 organic fertilizer. A 4 × 3 factorial randomized complete-block experimental design with two blocks and five replicates per treatment was repeated twice in the greenhouse. For each experiment a total of three center cells were harvested from each replicate for analysis using the WinRhizo Pro root scanning system (Regent Instruments Inc., Montreal). Three cells per treatment were also transplanted into 8-inch pots to stimulate field transplanting. Based on mean separation tests (n = 30), increased cell volume before transplanting significantly increased root surface area, average diameter, and root volume after transplanting (n = 18). Mean root surface area for a 29-mL cell was 30% greater than a 15-mL cell before transplanting and 22% greater after transplanting. Plug cell volume also significantly impacted shoot and root biomass (P <0.0001). A 14-mL increase in cell volume resulted in a root and shoot dry weight increase of about 15%.
Sara Arscott and Irwin Goldman
accumulation in a rapid-cycling Brassica oleracea population responds to increasing sodium selenate concentrations J. Plant Nutr. 22 927 937 Lefsrud, M.G. Kopsell, D.A. Kopsell, D.E. Randle, W.M. 2006 Kale carotenoids are unaffected by, whereas biomass
Mark G. Lefsrud, Dean A. Kopsell, David E. Kopsell, and Joanne Curran-Celentano
Crop plants are adversely affected by a variety of environmental factors, with air temperature being one of the most influential. Plants have developed a number of methods in the adaptation to air temperature variations. However, there is limited research to determine what impact air temperature has on the production of secondary plant compounds, such as carotenoid pigments. Kale (Brassica oleracea L.) and spinach (Spinacia oleracea L.) have high concentrations of lutein and β-carotene carotenoids. The objectives of this study were to determine the effects of different growing air temperatures on plant biomass production and the accumulation of elemental nutrients, lutein, β-carotene, and chlorophyll pigments in the leaves of kale and spinach. Plants were grown in nutrient solutions in growth chambers at air temperatures of 15, 20, 25, and 30 °C for `Winterbor' kale and 10, 15, 20, and 25 °C for `Melody' spinach. Maximum tissue lutein and β-carotene concentration occurred at 30 °C for kale and 10 °C for spinach. Highest carotenoid accumulations were 16.1 and 11.2 mg/100 g fresh mass for lutein and 13.0 and 10.9 mg/100 g fresh mass for β-carotene for the kale and spinach, respectively. Lutein and β-carotene concentration increased linearly with increasing air temperatures for kale, but the same pigments showed a linear decrease in concentration for increasing air temperatures for spinach. Quantifying the effects of air temperature on carotenoid accumulation in kale and spinach, expressed on a fresh mass basis, is important for growers producing these crops for fresh markets.
M. Pilar Bañados, Bernadine C. Strik, David R. Bryla, and Timothy L. Righetti
biomass of 1057 kg·ha −1 DW ( Fig. 1A ). In 0N plants, net biomass accumulation from planting to the beginning of the second growing season (after pruning in Feb. 2003) was 474 kg·ha −1 with losses of 119 kg·ha −1 in senescing leaves and 101 kg·ha −1
Jon R. Johnson
`Vates' collard (Brassica oleracea L. Acephala Group) was more susceptible to tipburn than `Blue Max' or “Heavi Crop' in field and nutrient solution culture experiments. The root system of Vates' was smaller than that of `Blue Max' in all experiments. Because of its smaller root system, `Vates' may be more susceptible to moisture stress than `Blue Max' when grown under high-temperature conditions on sandy soils, thus increasing susceptibility to tipburn. Root system size, however, did not influence Ca accumulation or Ca concentration in the plants. Calcium accumulation rate was higher for `Blue Max' and `Heavi Crop' than for Yates' during the 3rd through the 5th weeks of culture, in a nutrient solution that contained 5 mM Ca. Calcium efficiency ratio (CaER, milligrams of dry matter produced per milligram of Ca in tissue) for young leaves was higher for `Blue Max' and `Heavi Crop' than “for `Vates' when plants were grown with 1 mM Ca, which may partly explain the greater susceptibility of `Vates' to tipburn. `Heavi Crop' had a higher total plant CaER than `Blue Max' when grown with 5 mM Ca.
Mark G. Lefsrud and Dean A. Kopsell
Plant growing systems have consistently utilized the standard Earth day as the radiation cycle for plant growth. However, the radiation cycle can easily be controlled by using automated systems to regulate the exact amount of time plants are exposed to irradiation (and darkness). This experiment investigated the influence of different radiation cycles on plant growth, chlorophyll and carotenoid pigment accumulation in kale (Brassica oleracea L. var. acephala D.C). Kale plants were grown in growth chambers in nutrient solution culture under radiation cycle treatments of 2, 12, 24, and 48 h, with 50% irradiance and 50% darkness during each time period. Total irradiation throughout the experiment was the same for each treatment. Radiation cycle treatments significantly affected kale fresh mass, dry mass, chlorophyll a and b, lutein, and beta-carotene. Maximum fresh mass occurred under the 2-h radiation cycle treatment. The maximum dry mass occurred under the 12-h radiation cycle treatment, which coincided with the maximum accumulation of lutein, beta-carotene, and chlorophyll a, expressed on a fresh mass basis. The minimum fresh mass occurred during the 24 h radiation cycle treatment, which coincided with the largest chlorophyll b accumulation. Increased levels of chlorophyll, lutein and beta-carotene were not required to achieve maximum fresh mass production. Environmental manipulation of carotenoid production in kale is possible. Increases in carotenoid concentrations would be expected to increase their nutritional contribution to the diet.