INTRODUCTION TO ASCLEPIAS CALIFORNICA
The terrestrial plant, Asclepias californica, is the primary food source for Monarch butterflies. It can only germinate and produce seeds if provided with the proper environmental influence. The California milkweed’s population is spread out in the southern and coastal areas of California where there are flat lands and grassy slopes. It can also grow up to three feet tall and have clumps consisting of multiple stems that are a couple of feet in width. Unlike the Monarch butterflies, other animals avoid this plant mainly because of its toxic resinoids, alkaloids, and cardiac glycosides. On the contrary, Monarch butterflies ingest the alkaloids contained by this plant for protection from predators such as slugs. Not only is it used by the Monarch butterflies, but humans as well. Its dried and powdered form can be applied onto skin with a spider bite.
And latex contained in the stems and leaves can also make rubber. Like people, seedlings need to grow up nourished and strong to repopulate. Its necessities include the right temperature, amounts of water, season, surrounding air, amount of sunlight, and soil conditions. In addition, a fungus known as mycorrhizae will develop within the roots of this plant and eventually undergo symbioses. Fortunately, these mycorrhizal fungi form mutualistic relationships; which will enable the plant to absorb a sufficient amount of water, consume nutrients from the soil, and prevent pathogens from harming the roots. An experiment on the germination and seed production will be conducted with and without the use of the mycorrhizal fungi to determine its level of influence on the Asclepias californica plant’s progress. The plants will be raised and nursed in a greenhouse. Overall, the healthy seedlings will be given away for donation to the butterfly gardens located in Orange County.
METHOD:
The seedling project was conducted from October 10th, 2012 to November 26th, 2012. We collected 10 pots and labeled all of them with two different group names. Five of the plants that were used in the experiment were exposed to the mycorrhizae and were therefore named “ Group M”. On the other hand, the other half contained fungicide which we named “Group F”. In the first layer, we added one inch of gravel bark into the bottom of each pot, and one inch of soil for the next one. Then we proceeded by adding 10 centimeters cubed of either mycorrhizae or fungicide to the appropriate labels. Furthermore, we added a half inch of soil for all 10 pots to serve as the third layer in the pot. Lastly, three seeds were placed inside each pot and were covered by a half inch of soil. Ultimately, we watered each pot with 100 milliliters of water.
We kept all the pots in the greenhouse where they were watered and checked regularly. On October 17th,2012 , the first two germinated seeds were found in both groups under the pot named M2 for mycorrhizal group and F4 for the fungicide group. The result was unexpected, the surface of the soil seemed to be dried out most probably due to the seed’s lack of water needed for germination. Therefore, we added 100 milliliters of water for each pot again. The following data will show the result for germination after the second visit on October 29th.
GERMINATION RATE
POT NUMBER
GROUP F
GROUP M
1
2
2
2
1
1
3
2
3
4
2
1
5
1
2
According to this chart, there was not much difference between the two groups for germination. We can conclude that the mycorrhizal treatment did not affect germination for the seeds. However, external factors such as water, oxygen, and temperature play an important role in the process. On the other hand, the quality of the seed (dormant seed) was also the reason for its delayed germination. Besides germination, the height and thickness of the stem are very important factors that help us determine the success of the seeding. The data below tracked the height (in cm) of each tree which was measured on November 19th, 2012.
DIFFERENCE IN HEIGHT
POT #
GROUP F
GROUP M
Plant 1
Plant 2
Plant 3
Plant 1
Plant 2
Plant 3
1
5cm
4.3cm
0
8cm
7.8cm
0
2
7cm
0
0
9cm
0
0
3
6cm
6.2cm
0
6cm
4cm
2.5cm
4
4.8cm
4cm
0
4.6cm
0
0
5
6cm
0
0
9cm
7cm
0
In average, the plants under the treatment of mycorrhizal (Group M) were taller than the ones in group F ( Fungicide). We can take the average height of the plants by using the formula: ∆H= total height (cm)/ total number of plants + The average height of the plants in group M: ∆HM = 6.4 cm + The average height of the plants in group F: ∆HF = 5.4 cm
Besides the height of the plant, we also noticed the thickness of the stem. As it grows in length, the stem also grows in width. All the plants we have demonstrated noticeable changes in growth. The stem was thicker after the third visit, but compared to the plants of the other groups in class, they were skinny and scrubby.
We noticed that the soil was wet on the surface in all of the pots which results in a waterlogged soil. Too much water in the soil meant that the plant would lose nutrients, and oxygen absorption will be retarded during respiration which would overall lead to an undeveloped plant. Furthermore, a wet soil was a good environment to promote fungus. On the fourth time visit, four out of five pots of group F had a few fungi growing on the surface of the soil. After two weeks, all the leaves of these plants withered. However, all the plants belonging to group M have not had any signs of fungus infection and still grew taller. In other words, mycorrhizae inside the soil (or on the root ) generally protected the plants from harmful fungi.
CONCLUSION
After one and a half months since planting the seeds, even though the result was not as good as we might have expected (considering it was unsuccessful in seeding). Base on the last record, all the plants were skinny and unhealthy, some were dying. However, we have found some important facts in order to get a successful seedling in the future. These things that are important in a successful seedling is having the correct water amounts, providing enough oxygen, and providing the right temperature. Especially, we had proofs to demonstrate the important roles of mycorrhizae to the plants. As we know , mycorrhizae helps plants obtain nutrients such as nitrogen and phosphorus from the environment and improve water uptake by plant roots. Thus, mycorrhizae did not have any effect on the germination rate of the seed ( “ Germination data”).
According to the data “Difference in height”, most the plans on Mycorrihae group were grown taller than Fungicide group, so we knew mycorrhizae have already worked on the root of the plants we had. The plants on group M absorbed more nutrient and water than group F , so they were taller. Furthermore, we had the most interesting proof which was created by a practical mistake; it proved the pathogenic fungi could do nothing to harm the host plants of mycorrhiae. It meant Mycorrhizae did a good job to protect the plant’s root from pathogenic fungi attack. As we saw on the picture, none harmful fungi grew on group M plants. All the leaves were green and healthy, except the stems were skinny and unhealthy due by lacking of potassium in soil.
Since this seedling project, we have observed so many interesting facts to do gardener. Planting a healthy tree was not as easy as we thought. To be able balance the three external factors :water, oxygen, and temperature is really tough, it requests a lot of times, and gadener experiences. Based on the mistake we did,waterted a young plant with too much water and too fast it caused waterlogged soil and erosion. So the plants could not comletely develop because of over lacking nutrient. Eventhough with the company of mycorrhizal on the root, the plant can only grow in height, not in width.
WORKS CITED
“Medicinal Herbs California Milkweed Asclepias Californica.”
Naturalmedicinalherbs.net. Plants For A Future, n.d. Web. 29 Oct. 2012. “Asclepias Californica.” Wikipedia. Wikimedia Foundation, July 2012. Web. 29 Oct. 2012. .
