Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.

Changes in heated and autoclaved forest soils of S.E. Australia. I. Carbon and nitrogen.

Abstract: The effect of heating and autoclaving on extractable nitrogen, N mineralisation and C metabolism was studied by heating five forest soils in the laboratory, simulating the range of effects of heat due to bushfire. Top soil (0–5 cm) was heated to 60 °C, 120 °C and 250 °C for 30 minutes; unheated soil was taken as a control. Samples of the soil heated to 250 °C were also inoculated with fresh soil to accelerate the recovery of the microbial population. Soil autoclaving was carried out as another heat treatment (moist heat). Soils were analysed immediately after heating and 3 times during seven months of incubation to assess immediate and longer-term effects of heating. Extractable N (organic and mineral forms) increased after heating to 120 °C, but decreased with further heating to 250 °C suggesting the volatilisation of N. N associated with microbial biomass diminished with heating and was barely detectable after the 250 °C treatment. Microbial biomass was an important source of soluble N in heated soils, and only partly recovered during subsequent long incubation. The amount of N mineralised during incubation depended on both soil and temperature. Nitrification did not occur when soils were heated to 250 °C (with or without inoculum), or after autoclaving, demonstrating the high sensitivity of nitrifiers to heat. At the beginning of soil incubation, respiration was enhanced in heated soils (250 °C, 250 °C inoculated) and autoclaved soils, but after 30 days of incubation respiration decreased to values either similar to or lower than those in control. This respiration pattern indicated that a fraction of labile C was released by heating, which was quickly mineralised within 30 days of incubation. These results demonstrate some effects of soil heating on C and N dynamics in forest soils.

Motility of the Turtle Embryo, Chelydra serpentina (Linné)

Abstract: Periodic motility of turtle embryos was observed during their incubation periods (60 ± 5 days). Cyclic activity was first observed between days 10 to 14; it increased to a peak level of 50 percent of the standard observation period on day 30 ± 5, then declined to low levels until hatching activities were initiated. During the first third of the incubation period, motility of the turtles closely resembled that previously described for chick embryos at similar stages of development.

Meeting embryonic requirements of broilers throughout incubation: a review

Abstract: During incubation of chicken embryos, environmental conditions, such as temperature, relative humidity, and CO 2 concentration, must be controlled to meet embryonic requirements that change during the different phases of embryonic development. In the current review, the effects of embryo temperature, egg weight loss, and CO 2 concentration on hatchability, hatchling quality, and subsequent performance are discussed from an embryonic point of view. In addition, new insights related to the incubation process are described. Several studies have shown that a constant eggshell temperature (EST) of 37.5 to 38.0°C throughout incubation results in the highest hatchability, hatchling quality, and subsequent performance. Egg weight loss must be between 6.5 and 14.0% of the initial egg weight, to obtain an adequate air cell size before the embryo internally pips. An increased CO 2 concentration during the developmental phase of incubation (first 10 days) can accelerate embryonic development and hatchability, but the physiological mechanisms of this acceleration are not completely understood. Effects of ar increased CO 2 concentration during late incubation also need further investigation. The preincubation warming profile, thermal manipulation, and in ovo feeding are new insights related to the incubation process and show that the optimal situation for the embryo during incubation highly depends on the conditions of the eggs before (storage duration) and during incubation (environmental conditions) and on the conditions of the chickens after hatching (environmental temperature).

Comparison of direct vs fumigation incubation microbial biomass estimates from ectomycorrhizal mat and non-mat soils

Abstract: Direct estimates of microbial biomass were compared to chloroform fumigation incubation estimates of microbial biomass using samples collected from mesic forest stands. Paired soil samples were collected from ectomycorrhizal mats, which contain visible amounts of fungal material, and from non-mat areas immediately adjacent to the mats but which contain no visible fungal material. As much as 30–50% of the dry wt of soil collected from ectomycorrhizal mats can be comprised of strictly fungal biomass. Direct estimates of microbial biomass from both mat and non-mat soils were 10–300 times higher than biomass estimates obtained using the fumigation incubation method. Fumigation incubation estimates of microbial biomass showed little seasonal variation, while direct estimates revealed that microbial biomass peaked during both the spring and fall when rainfall and temperatures were optimal and were lowest during the dry summer. We compared our values to ones reported for shortgrass prairies and in Jenkinson's original fumigation incubation paper. Fumigation incubation estimates indicated that microbial biomass carbon was the same in both prairie and forest soils, about 0.5 mg C g −1 soil. Direct estimates showed that microbial biomass was actually greater, by factors of 10–300, in these forest soils. Some forest soils, for which fumigation incubation indicated very low microbial biomass, contained visible amounts of fungal hyphae. Our conclusion is that fumigation incubation does not necessarily measure microbial biomass, and that the error can be extremely high when soils contain high quantities of fungal biomass.