). The compound has recently been referred to as "karrikinolide" ( Commander et al., 2008 ). The action of smoke in promoting seed germination in many species is attributed to the presence of this compound ( Soos et al., 2009 ). Dixon and Roche (1995
Jenjira Chumpookam, Huey-Ling Lin, and Ching-Chang Shiesh
Kun Jia, Michelle DaCosta, and J. Scott Ebdon
adequate density and uniformity for play ( Green et al., 2018 ). Adverse conditions such as cold soil temperatures (≈10 °C) typical of early spring plantings in temperate areas of the northeastern United States can delay seed germination and diminish
Mohamad-Hossein Sheikh-Mohamadi, Nematollah Etemadi, Ali Nikbakht, Mostafa Farajpour, Mostafa Arab, and Mohammad Mahdi Majidi
becoming a main environmental factor limiting seed germination and seedling growth in arid and semiarid regions ( Sekmen et al., 2012 ). Different levels of salinity stress can affect turfgrass adversely. These may include a series of morphological
Tyler Hoskins and Ryan N. Contreras
durations to evaluate the effects on seed germination, 2) to evaluate growth effects from various treatments, and 3) to determine whether the relative frequency of polyembryony is affected by EMS treatment. Materials and Methods Plant material and experiment
Andrew P. Vovides and Carlos G. Iglesias
K. E. Cushman, H. B. Pemberton, B. G. Cobb, and W. E. Roberson
Viola tricolor seed were exposed to aerated solutions of water or 300 or 400 mM NaCl for 0, 2, 4, 6, or 8 days. After priming treatments, seed were air dried, placed on moist filter paper in petri dishes, and set in dark growth chambers at 18 or 30°C for germination. priming for 6 days in water increased germination of `Crystal Bowl Yellow' seed from 80 to 88% when germinated at 30 °. Untreated seed germination was 92% at 18°. Priming for 6 days in 300 mM NaCl improved germination of `Majestic Giant Blue' seed from 57 to 76% when germinated at 30°. Untreated seed germination was 80% at 18°. These data indicate that seed priming could be used to improve summer germination of a cool season annual. Priming increased germination at the higher than optimum temperature (30°) to levels similar to that for the optimum temperature (18°). However, the best priming solution depended on the cultivar.
A local ground orchid, Spathoglottis plicata Blume, and coconut, Cocos nucifera L., were used in the classroom to teach seed germination. S. plicata, a common orchid on Guam, was utilized to demonstrate the aseptic culture of seeds under non-sterile conditions. The procedures were done in the classroom without a laminar air-flow cabinet. Nonsterile seeds were sown on growing media which were prepared without autoclaving, but by incorporating sodium hypochlorite into the media. Students had a high rate of success in germinating the orchid seeds without contamination by spraying sodium hypochlorite on the seeds. Different stages of coconut seed development were presented to students by simply cutting coconut in half. Unique features and botanical terms of coconut seed development can be taught throughout the year. Teaching materials on seed germination of the two tropical plants are being developed by print-on-demand methods.
Wayne L. Schrader
Three trials were conducted in 1989 to evaluate the effects of chilling, freezing, growth regulator, and acid scarification treatments on the seed germination of two artichoke varieties. Soaking seed in a 500, 1000, or 2000 ppm ethephon solution for 5 minutes significantly increased the rate and uniformity of germination. Chilling, freezing, gibberellin, and cytokinin treatments did not affect germination rate. Freezing moistened seed and acid scarification significantly delayed germination. Ethephon treatments did not affect subsequent seedling development.
Bing-Rui Ni and Kent J. Bradford
Cell growth models were applied to characterize the response of seed germination, based upon the timing of radicle emergence, to y and ABA. Using probit analysis, three basic parameters can be derived to describe the population characteristics of seed lots. In the response of seed germination to osmotic stress, these three parameters are the “hydrotime constant” (q H), the mean base water potential (y b), and the standard deviation (s b) population. In the response to ABA, they are the “ABA-time constant” (q ABA), the mean base ABA concentration (ABAb), and the standard deviation (s ABAb) of the seed population. Using only these three parameters, germination time courses can be predicted at any corresponding medium y or ABA concentration. In the presence of both ABA and osmotic stress, the same parameters can be used to predict seed germination time courses with any combination of y and ABA concentration. The water relations model and the ABA model were additive and it appeared that the two factors slowed down germination independently. Effects of osmotic stress and ABA on the parameters in Lockhart equation are also discussed.
S.M. Hum-Musser, T.E. Morelock, J.B. Murphy, and R.L. Henry
Seed germination of spinach (Spinacia oleracea L.) is partially inhibited by a high germination temperature (35 °C). Tolerance of high germination temperatures varies widely depending on the variety used. We ascertained that seed germination of these spinach varieties was thermoinhibited at 35 °C and secondary dormancy was not induced as seeds germinated when transferred to optimum germination conditions (20 °C). Treatment with 99% oxygen and 10 ppm kinetin significantly increased germination of thermoinhibited varieties at 35 °C. During heat stress, all organisms produce heat shock proteins (HSPs), which may function as molecular chaperons, are possibly required for the development of thermotolerance, and may be crucial for cell survival during heat stress. Western blotting of SDS-PAGE gels using antibodies to various heat shock proteins indicated that spinach varieties with the highest degree of thermotolerance have higher levels of HSP expression than varieties with the lowest degree of thermotolerance during germination. These results suggest that thermotolerance could be further improved, either through a breeding program or possibly by genetic engineering.