| Summary: | 碩士 === 國立屏東科技大學 === 森林系所 === 95 === Typhoon Haitang, which hit the southern Taiwan in July, 2005, badly damaged the branches and leaves of the west coast forest in the Kenting National Park. Consequently, the solar radiation in the forest increased, and that caused the seedlings of Aritolochia zollingerana to greatly germinate. The study started from October, 2005 through March, 2007, monitored the dynamic of the survival, growth, and mortality the Aristolochia zollingerana seedlings in Eluanbi Park, and explored the environmental and biological factors that affected the death of the seedling groups. In addition, the study tested the photosynthesis of the plants of Aristolochia zollingerana in the experimental place, and with man-made shade, the researcher observed their responses of growth and biological activities in conditions of various light quantities so as to understand their tolerance range to light quantity.
The study located 14 small places in Eluanbi Park, set a sample area covering one square meter in each place, recorded the light quantities and the survival, death, or rebirth of the seedlings every other week, and as well, recorded the growth of the seedlings by their height. In October, 2005, the total numbers of the seedlings were 558. The range in each sample area was from 9 to 129. At most, there were 10 to 19 plants, including 4 sample areas. Still there were three sample areas, where there were 50 to 59 plants. Until February and April, 2006, the survival rates of the original seedlings were respectively 62% and 40%, and as one year past, the rate was only 7%. The number of the newborn seedling groups decreased as time went by. The strong wind and salt accompanying the typhoon brought about the damage of the branches and leaves of the canopy in the experimental place. The relative light quantity under the forest was 12% in the beginning of the study in October, 2005, and four months later, it became 7%, and when the time was December, 2006, it went down to 1.2%. During the first three months, the survival rate of the seedlings in each sample area showed significantly positive relativity to light quantity. After February, 2006, however, the decrease of the survival rate was not significantly relative to the light quantity of the sample areas. In February, 2006, the plants of Aristolochia zollingerana still grew higher, but in April, 2006, there appeared a great number of the larvae of Pachliopta aristolochiae interpositus Fruhstorfer gnawing the plants, which made the net height growth of the plants turn negative. The study found out that within three months after being gnawing by the larvae of Pachliopta aristolochiae interpositus Fruhstorfer for the first time, the death rates of the plants in lower light quantity sample areas were up to more than 50%, but those in L10-20 sample areas were only 10%.
In Eluanbi Park, the light saturated photosynthetic of the adult sun-leaves of Aristolochia zollingerana was 6.38 μmol m-2s-1, which was significantly higher than 2.61μmol m-2s-1of their shade-leaves. By testing the daily change of biological activities, the researcher learned that the net photosynthesis of the sun-leaves of Aristolochia zollingerana tended to descend when the light quantity was more than 1200 μmol m-2s-1. The average net photosynthesis of the sun-leaves was 3.7 μmol m-2s-1, higher than 0.8 μmol m-2s-1 of shade-leaves.
In order to understand the plants’ responses of growth and biological activities in conditions of various light quantities, the researcher cultivated one-year-old plants of Aristolochia zollingerana under four shade arrangements for nine months. As a result, it showed that the performances of the plants of Aristolochia zollingerana , including biomass, plant height, and total leaf area, were not significantly different among 49%, 23%, and 2% light quantities, but their performances were all significantly higher than those of full light plants. As for biological activities, the light saturated photosynthetic of full light plants was higher, significantly higher than those of the plants under the other three shade arrangements.
In conclusion, the survival rate of the newborn seedlings of Aristolochia zollingerana was only 1.8% after 17 months. From October, 2005 through February, 2006, the survival rate of the newborn seedlings of Aristolochia zollingerana was positively relative to the light quantity in the sample areas. But from March through October, 2006, the survival rate decreased because of the gnawing of the larvae of Pachliopta aristolochiae interpositus Fruhstorfer. In man-made shade conditions, the performances of the plants of Aristolochia zollingerana under full light would significantly lower than those of plants under shade arrangements. In terms of biological characters, Aristolochia zollingerana’s photosynthesis would show the phenomenon of photoinhibition under high light quantity. Therefore, the seedlings of Aristolochia zollingerana don’t need full light to grow; they can grow well in partly shaded environment.
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