Physiological esponses of P. formosanum, F. formosana and M. kusanoi to Salty Smog Stress

• Main Authors: Lin, Chien-Horng, 林建宏
• Other Authors: Lin Jenq-Horng
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/93118802255694551277

碩士 === 國立中興大學 === 植物學系 === 85 === Native seedlings of Palaquium formosanum, Fraxinus formosana and Machiluskusanoi were grown in a greenhouse . The maximum soil water contents were controlled to be 50.4%, 69.6% and 88.8% with automatic watering system using polyvinylformal strips . Periodically, artificial sea water was sprayed evenly on the leaves. Several physiological responses of these seedlings to salty smog was examined. The results showed that the growth of all seedlings were inhibited by salty smog treatment. The extent of growth inhibition was the highest in F. formosana and the lowest in P. formosanum. The degree of inhibition in the measurements of leaf water content, water potential, osmotic potential, turgor pressure and absorption of water was also the highest in F. formosana and the lowest in P. formosanum. During salty smog treatment, the leaf water potential, water content and absorption water of of F. formosana decreased continously and was never recovered, whereas less severe effects were found in P. formosanum and M.kusanoi . In analysis of leaf stomatal conductance and transpiration,we also found that all followed the same trends as the most serious inF. formosana and the slightest in P. formosanum. As for photosynthesis, chlorophyll contents in all seedlings were decreased by salty smog treatment and the degree of decrease was the highest in F. formosana during treatment. The activity of Rubisco was also inhibited significantly in F. formosana. These observations were similar to those of M. kusanoi but the effect was less severe. There were no difference of Rubisco activity between control and salty-smog treatment in P. formosanum. These results showed that P. formosanum has higher tolerance to salty smog. Although M. kusanoi are more sensitive to salty smog, it still can tolerate for short term treatment. And F. formosana is most affected by salty smog treatment. As for osmotic regulation, all three species were accumulated soluble sugars and proline. Betaine was also found to accumulate in P. formosanum. These results showed that P. formosanum can accumulate certain osmolytes for osmotic adjustment and protein under environmental stresses. P. formosanum can also efficiently regulate the content of carbon and nitrogen in order to acclimate salty smog. F. formosana is sensitive to salty smog and the expression of physiological responses are inhibited, and growth is decreased during stress. M. kusanoi has mild-tolerance to salty smog in short term exposure to salty smog, but still develops inhibitory symptoms as stress persisted.