Search Results

You are looking at 131 - 140 of 648 items for :

Clear All

Seed from six species of the Apiaceae and six parsley (Petroselinum crispum L.) cultivars with three seed lots of each parsley cultivar were tested for the presence of germination inhibiting substances. Aqueous leachate from seed of all six species inhibited germination of lettuce (Lactuca sativa L.) and radish (Raphanus sativus L.). Leachate from root parsley seeds (P. crispum tuberosum) were least inhibitory, while leachate from celery and celeriac (both Apium graveolens L.) seeds were most inhibitory. Inhibitory concentrations in leachate varied by seed lot within a cultivar. Aqueous leachate of seeds from the primary umbels caused less inhibition of germination than did leachate from tertiary umbels. Washing parsley seeds in aerated water for 3 hours or more removed some of the germination inhibitory substance as indicated by the germination bioassay. An aqueous extract prepared from seedcoat tissue, removed during mechanical scarification, inhibited radish seed germination; inhibition was proportional to the duration of scarification and the amount of seedcoat tissue extracted. Parsley seeds scarified ≤60 minutes germinated at rates comparable to washed seeds, but longer scarification time reduced germination. Washing seeds of Apiaceae prior to commercial drying and cleaning may be a practical solution for removal of inhibitors.

Free access

sucrose from soilless growing medium leachate were Bacillus spp. ( Table 2 , Fig. 8 ). Biofilm production by Curtobacterium pussillum , Paenibacillus lautus , and Brevundimonas is less common than in Bacillus spp., which are common biofilm

Free access

; Plant Products, Brampton, ON, Canada). Measurements. Shoot dry weight was measured at the end of the experiment to assess plant growth over each respective trial period. In addition, biweekly EC and pH measurements of growing mix leachate were collected

Free access

(EC) and accelerated aging for determining seed vigor ( ISTA, 2010 ); however, seed companies use a variety of vigor-testing methods ( Copeland and McDonald, 2001 ). Imbibitional damage of pea cotyledons resulted in higher EC of leachate when the

Free access

`Lynwood Gold' forsythia and `Jessica' chrysanthemum were grown for 12 weeks in a nursery mix consisting of 5 parts composted pine bark, 1 part composted hardwood bark and 1 part sand. Fertilization was by topdress applications of composted poultry manure at rates of 1, 2 and 3 g N per container, resin coated slow release fertilizer at 3 g N per container, or with constant liquid fertilization at 200 mg N per liter. Leachate samples were collected weekly and nitrate, nitrite, ammonium and total nitrogen determined. At 12 weeks, plant dry weight and the amount of nitrogen in the plant, media and leachate determined. Total nitrogen loss in the leachate for the compost was rapid during the first three weeks and then fell to low levels. The resin coated fertilizer released a higher and constant nitrogen flux during the study than the composted manure but total nitrogen loss over the 12 week period was lower than for compost. The leachate nitrogen in the constant liquid fertilization treatment increased during the study. The relative proportion of nitrogen in the medium, compost and leachate will be discussed.

Free access

Seeds of two shrunken-2 (sh2) sweet corn (Zea mays L.) cultivars, Crisp N' Sweet 711 and How Sweet It Is were used to analyze seed quality factor differences between the cultivars. Negative correlations occurred among germination percentage and imbibition, electric conductivity, potassium concentration and total soluble sugars of the seed leachate. Imbibition and total soluble sugar in the leachate significantly increased as imbibition temperature increased from 5°C to 25°C in both cultivars. A significant increase in conductivity of the leachate also occurred in `Crisp N' Sweet 711' when temperature increased. Cracks in the seed coat were more frequent in `How Sweet It Is' than `Crisp N' Sweet 711'. The higher concentrations of soluble sugars in the seed, greater imbibition rate, leakage conductivity, potassium and sugar concentration in the leachate may have been directly related to the poorer seed quality of `How Sweet It Is'. The alteration in cell membrane structure caused by a rapid water uptake in `How Sweet It Is' may have led to the high concentration of electrolytes in the seed leachate. This, in turn, might provide a greater nutritive subtrate for fungi development.

Free access

`Barbados' New Guinea impatiens were grown in 500 cm3 pots under drip irrigation and fertilized with solutions containing either 6, 12 or 18 mM N at two leaching fractions (0 and 30-50%). Soil moisture within the pots was characterized and controlled using electronic microtensiometers. The 0% leachate plants were automatically irrigated to container capacity when the soil tension in the pot reached 4.5 kPa, while the 30-50% leachate plants were irrigated for five minutes at a time whenever the soil tension was at or slightly greater than 4.5 kPa. After 6 weeks, there was only a slight effect of fertilizer concentration on height, width, or leaf number of the plants. Plants grown under 0% leachate did not differ significantly in overall growth and performance than those that were leached at every irrigation. Electrical conductivity of the potting media was highest in the 0% leachate treatments (highest readings in upper one-third of the pot) and increased as fertilizer concentration increased. After 6 weeks of production, total volume of irrigation solution leached per pot range6 from 2.2 to 3.6 liters for plants grown under the 30-50% leachate treatment.

Free access

as needed, and plots were hand-weeded as needed. Soil water leachates were collected using suction cup lysimeters (Soil Moisture Equipment Co., Santa Barbara, CA) 0.6 m long and 5.1 cm in diameter with a ceramic cap 7.6 cm long and 5.1 cm wide. Four

Free access

The potential mechanism of susceptibility of apple (Malus ×domestica Borkh.) fruit to sooty blotch due to carbohydrate leachates was examined. Fruit received applications of 0.5% apple juice to the fruit cuticle in order to mimic leachates. Nine cultivars of apple were selected from a variety block of potentially disease resistant breeding stock. Intact fruit on selected limbs received 0.5% apple juice applications on eight evenly spaced occasions during development. Trees received a minimal fungicide program only. Leachate samples from the fruit cuticles were collected monthly by immersion of whole, detached fruit in dH2O for 60 min. At harvest, fruit were evaluated for skin roughness, fruit rots, sooty blotch, sooty mold, flyspeck, and insect injury. Despite drought conditions, sooty blotch and sooty mold showed strong increases in disease intensity ratings, while flyspeck and skin texture damage showed moderate increases in intensity due to the dilute juice applications. Fruit rots and insect damage were unaffected by the juice applications.

Free access

A study was conducted to develop and demonstrate a practical and accurate method of applying the Pour-Through nutrient extraction procedure to bedding flats and plug trays. The Pour-Through technique involves pouring a known volume of water on previously saturated medium, and collecting the leachate which is pushed out the bottom of the container. The volume of applied water necessary to conduct a bedding flat or plug tray Pour-Through was determined based on leachate pH and conductivity. The sensitivity of the Pour-Through technique when applied to bedding flats and plug trays was determined using varying rates of lime incorporated media and fertilizer. The leachate was analyzed for pH and conductivity. Results indicate that the technique can be used effectively on bedding flats and plug trays.

Free access