The Holly and the Ozone
"Holly may not be celebrating the festive season !!!
This well known plant that was used to keep evil spirits at bay and bring good luck is now facing its own problems, according to two recently published studies (Environmental Pollution vol. 145, pp 171 & 355) by researchers Dr. Jon Ranford & Dr. Kevin Reiling at Staffordshire University.
They have looked at the impact of ozone air pollution over 4 years and have come across some startling results.
After subjecting young holly plants to a typical summer dose of ozone for 28 days they found these plants lost their leaves up to 4 months earlier, lost more water through their stomata and had shorter roots and shoots, than plants subjected to clean air . There were also serious carry-over effects to the plants with the following year's new leaves being lost up to 2 months earlier and significantly lower leaves being produced in the following three years after ozone exposure. A reduction in leaves means the plants will produce less photosynthetic products for growth and repair and may effect how well holly survives in its habitat. The first study also indicated a reduction in frost tolerance with more leaves being lost over the winter period, so the second study using the same method as before, then placed holly plants in special refrigerated cabinets which dropped down to -5/-10/-15 C at night. The plants subjected to ozone had significantly higher loss of electrolytes from their cells at all temperatures and had up to 30 % reduction in winter survival.
Using a technique called Chlorophyll Fluorescence the research also showed the plants were under significantly more stress if they received the ozone and the sub zero temperatures. Dr Ranford says, 'the establishment and survival of holly in the ecosytem may"
This well known plant that was used to keep evil spirits at bay and bring good luck is now facing its own problems, according to two recently published studies (Environmental Pollution vol. 145, pp 171 & 355) by researchers Dr. Jon Ranford & Dr. Kevin Reiling at Staffordshire University.
They have looked at the impact of ozone air pollution over 4 years and have come across some startling results.
After subjecting young holly plants to a typical summer dose of ozone for 28 days they found these plants lost their leaves up to 4 months earlier, lost more water through their stomata and had shorter roots and shoots, than plants subjected to clean air . There were also serious carry-over effects to the plants with the following year's new leaves being lost up to 2 months earlier and significantly lower leaves being produced in the following three years after ozone exposure. A reduction in leaves means the plants will produce less photosynthetic products for growth and repair and may effect how well holly survives in its habitat. The first study also indicated a reduction in frost tolerance with more leaves being lost over the winter period, so the second study using the same method as before, then placed holly plants in special refrigerated cabinets which dropped down to -5/-10/-15 C at night. The plants subjected to ozone had significantly higher loss of electrolytes from their cells at all temperatures and had up to 30 % reduction in winter survival.
Using a technique called Chlorophyll Fluorescence the research also showed the plants were under significantly more stress if they received the ozone and the sub zero temperatures. Dr Ranford says, 'the establishment and survival of holly in the ecosytem may"
posted by joneboy at 9:26 PM
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