(295) Measuring and Reporting Growing Conditions in Controlled Environments

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1009B-1009
Author(s):  
Marc W. van Iersel

Do you accurately measure and report the growing conditions of your controlled environment experiments? Conditions in controlled environment plant growth rooms and chambers should be reported in detail. This is important to allow replication of experiments on plants, to compare results among facilities, and to avoid artefacts due to uncontrolled variables. The International Committee for Controlled Environment Guidelines, with representatives from the U.K. Controlled Environment Users' Group, the North American Committee on Controlled Environment Technology and Use (NCR-101), and Australasian Controlled Environment Working Group (ACEWG), has developed guidlines to report environmental conditions in controlled environment experiments. These guidelines include measurements of light, temperature, humidity, CO2, air speed, and fertility. A brochure with these guidelines and a sample paragraph on how to include this information in a manuscript will be available.

Paleobiology ◽  
2018 ◽  
Vol 44 (4) ◽  
pp. 736-757 ◽  
Author(s):  
Caitlin R. Keating-Bitonti ◽  
Jonathan L. Payne

AbstractEnergy availability influences natural selection on the ontogenetic histories of organisms. However, it remains unclear whether physiological controls on size remain constant throughout ontogeny or instead shift as organisms grow larger. Benthic foraminifera provide an opportunity to quantify and interpret the physicochemical controls on both initial (proloculus) and adult volumes across broad environmental gradients using first principles of cell physiology. Here, we measured proloculus and adult test dimensions of 129 modern rotaliid species from published images of holotype specimens, using holotype size to represent the maximum size of all species’ occurrences across the North American continental margin. We merged size data with mean annual temperature, dissolved oxygen concentration, particulate organic carbon flux, and seawater calcite saturation for 718 unique localities to quantify the relationship between physicochemical variables and among-species adult/proloculus size ratios. We find that correlation of community mean adult/proloculus size ratios with environmental parameters reflects covariation of adult test volume with environmental conditions. Among-species proloculus sizes do not covary identifiably with environmental conditions, consistent with the expectation that environmental constraints on organism size impose stronger selective pressures on adult forms due to lower surface area-to-volume ratios at larger sizes. Among-species adult/proloculus size ratios of foraminifera occurring in resource-limited environments are constrained by the limiting resource in addition to temperature. Identified limiting resources are food in oligotrophic waters and oxygen in oxygen minimum zones. Because among-species variations in adult/proloculus size ratios from the North American continental margin are primarily driven by the local environment’s influence on adult sizes, the evolution of foraminiferal sizes over the Phanerozoic may have been strongly influenced by changing oceanographic conditions. Furthermore, lack of correspondence between among-species proloculus sizes and environmental conditions suggests that offspring sizes in foraminifera are rarely limited by physiological constraints and are more susceptible to selection related to other aspects of fitness.


1977 ◽  
Vol 23 (11) ◽  
pp. 1529-1547 ◽  
Author(s):  
M. Lalonde ◽  
A. Quispel

The inoculation of the European Alnus glutinosa (L.) Gaertn. host plant by a crushed-nodule inoculum, prepared with the North-American Alnus crispa var. mollis Fern, root nodule, was successful. Fluorescein- and ferritin-labelled antibodies, specific against the A. crispa var. mollis root nodule endophyte (Lalonde et al. 1975), demonstrated the identity of this endophyte in the resulting nodules. The nodulation process of this abnormal host–endophyte system was studied by light and electron microscopy. An excretion of host blebs containing electron-dense polysaccharide material, resulting in the formation of exo-encapsulation threads containing presumptive endophytic bacterial cells, was associated with deformed root hairs. Originating from an exoen-capsulation thread, the endophyte penetrates the root hair cell and then migrates as a hypha toward the cortical cells of the root. Its migration in the cortical cells of the primary nodule results in the induction of a lateral root which develops as the true nodule. The ultrastructure of the A. crispa var. mollis endophyte developing in the primary and true nodule of the abnormal A. glutinosa host was similar to the one induced inside its normal A. crispa var. mollis host. The actinomycetal intruder was a branched and septate hypha able to produce septate vesicles. The endophyte was always encapsulated in an electron-dense polysaccharide material surrounded by a host plasma membrane envelope. However, in this abnormal host–endophyte system, the number of primary nodules formed per root system was drastically reduced, and their appearance was delayed by 1 to 2 weeks. The delayed nodules were effective in fixing nitrogen and able to support satisfactory plant growth in a nitrogen-free medium.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 555A-555
Author(s):  
Kimberly Swenson ◽  
Albert H. Markhart

A major limitation to plant growth in spring is low night temperatures. A variety of plant protection systems have been developed to keep the temperatures around the plant warmer than the ambient air. One system that has been developed for use with individual plants is a double walled stiff plastic tent. The space between the walls can be either filled with water or air. The top of the tent can be either open or closed. The objective of this investigation is to quantify the effect of these protection systems under controlled environmental conditions. Two wash-tubs filled with wet soil were placed in a controlled environment growth chamber. One tent was placed on the soil surface of each tub. The chamber was programmed to simulate a cold night. Temperatures started at 20 °C and then decreased to –5 °C at a rate of about 4 °C/h. During this time, ambient air temperature, jacket temperature, soil temperature, and air inside the tent was measured continuously with self-contained data loggers. Water filled tents delayed the time it took for the inside temperature to reach the outside temperature by 2 hours. There was not apparent effect on soil temperature. The effect of water vs. air-filled jackets and the effect of capping the top will also be presented.


2019 ◽  
Vol 10 (2) ◽  
pp. 391-409
Author(s):  
Benjamin D. Neece ◽  
Susan C. Loeb ◽  
David S. Jachowski

Abstract Bats are under threat from habitat loss, energy development, and the disease white-nose syndrome; therefore, an efficient and effective means to monitor bat populations is needed. The North American Bat Monitoring Program (NABat) was initiated in 2015 to provide standardized, large-scale monitoring to benefit bat biologists, managers, and policy makers. Given the recency of this program, our first objective was to determine the efficacy of implementing NABat. Further, because the probability of detecting a bat varies among species and survey conditions, our second objective was to determine factors affecting detection probabilities of bats using NABat acoustic surveys. We conducted surveys across South Carolina from mid-May through July 2015 and 2016. To determine efficacy of NABat, we compared species detections with historical known distributions and predicted distributions based on environmental occupancy models. To determine factors that affected detection probability, we evaluated support for predictive detection models for each species or species grouping. In general, we found that predicted distributions closely matched known distributions. However, we detected some species in ≤50% of cells within their ranges and others outside their ranges, suggesting NABat may also reveal new information about species distributions. Most species had higher detection probabilities at stationary points than mobile transects, but the influence of interrupted surveys, environmental conditions (e.g., temperature, rainfall, and wind) and habitat conditions often varied among species. Overall, our results suggest NABat is an effective and efficient method for monitoring many bat species, but we suggest that future efforts account for species-specific biological and behavioral characteristics influencing detection probability.


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