Leaf spectrum

Week 12: Your plant and the Leaf Economic Spectrum. Note: this assignment will be due Tuesday, April 22.

Look back at the research presentation (April 3) and find the slides about the leaf economic spectrum (LES; slides 9 and 10). Look at the information you have gathered on your plant. Where do you think it falls on the LES? What do you base this on? I am attaching a manuscript (Wright et al 2004) that explains the LES in a bit more detail. While you likely will not know the specific traits of your leaves (such as leaf %N or dark respiration rate), you should have a pretty good idea based on the ecology of the plant whether this is a plant that invest heavily in resource acquisition (live fast, die young) or resource retention (slow and steady) at the leaf level.

We focus on six key features of leaves that together capture many essentials of leaf economics. (1) Leafmass per area (LMA) measures the leaf dry-mass investment per unit of light-intercepting leaf area deployed. Species with high LMA have a thicker leaf blade or denser tissue, or both. (2) Photosynthetic assimilation rates measured under high light, ample soil moisture and ambient CO2 are here called photosynthetic capacity (Amass) for brevity. Photosynthetic capacity is influenced both by stomatal conductance and by the drawdown of CO2 concentration inside the leaf (carboxylation capacity). (3) Leaf nitrogen (N) is integral to the proteins of photosynthetic machinery, especially Rubisco8,13. The photosyn- theticmachineryisresponsiblefordrawdownofCO2 insidetheleaf, a process also affected by leaf structure14,15. (4) Leaf phosphorus (P) is found in nucleic acids, lipid membranes and bioenergetic mol- ecules such as ATP. Phosphorus derives from weathering of soil minerals at a site, in contrast to nitrogen, much of which may be fixed from the atmosphere by plants. (5) Dark respiration rate (Rmass) reflects metabolic expenditure of photosynthate in the leaf, especially protein turnover and phloem-loading of photo- synthates16. (6) Leaf lifespan (LL) describes the average duration of the revenue stream from each leaf constructed. Long LL requires
((Wright et al 2004)

Focusing on these different types, it is percieved that this plant is leaning towards the conservitive sides. There are lots of secondary compounds put into the plant. But the leaves only last two years, making it not as concervitive as say the pine.
I have writen a lot about these secondary compounds in earlier posts.
I do not know about the dray mass of the leaves, nitrogen efficiency, photosynthetic rates, or dark respritation rates.

Who's Eating Me?

Of the mullein plant, the entire plant is well defended against being eaten, with the exception of the pollen and nector, which the plant wants eaten for pollination. 

Mullein is full of lots of chemicals. It uses these chemicals as toxins to prevent it's leaves from being eaten. The toxins that can be found in the leaves are rotenone, a common pesticide, and anodyne, which is known for painkilling properties. Assumably either of these chemicals taken in high doses to a small insect if fatal. 

 rotenone

The seeds contains saponins, which was discussed in an earlier blog. According to Wikipedia saponins are soap-like forming acting as a effective pesticide and fungicide. The seeds are also bitter to the taste becase of the chemical. The seeds contain this to prevent animals and insects from eating and consuming the seeds.

Saponin

Mullein also has some biological defenses. It has thick hairs which prevent easy access to the leaves. It has very thick and coarse stems which are not easily digestible to mammals. 

This plant puts a lot of effort into its self to prevent being eaten. The irony is that because it is so full of othese chemicals, humans have been growing this plant to use it's leaves and seeds for teas and for other herbal remidies. There are many wife-tales about the benefits of this plant. To prevent repetition I have discussed the different uses humans have found for this plant in earlier blog posts.

Flowers

http://upload.wikimedia.org/wikipedia/commons/f/f4/Verbascum_thapsus_'Aaron's_Rod'_(Scrophulariaceae)_flower.JPG

Mullein flowers grow on large towers during the plant's second year. The flowers are small (1-2 inches) and yellow. Judging from the picture above: the flowers are perfect having both the female stamen/ovary and the male pollen producing anthers.

The flowers have 5 peddles, 5 anthers on 5 filaments, and one stigma. The anthers are very fuzzy to catch pollen onto any insect that passes. The stigma moves from the side to being in the middle as the flower ages. This is to prevent self-fertilization by having the anthers and stigma mature at different times.

http://www.thehealersbible.com/uploads/1/2/9/0/12907633/3563566_orig.jpg

V. Thapsus attracts generalized pollenates. Pictured below are small beetles and a honey bee pollenating the mullein flowers. The flower gives nectar and pollen as a reward for pollination. These flowers tend to grow abundantly in prairies and meadows so the changes of the generalized pollinator finding another mullein plant is likely.

http://cityjungle.files.wordpress.com/2013/07/img_1206.jpg?w=440&h=300&crop=1

http://1.bp.blogspot.com/-UEtrOOeh9qA/ThmMVCIc5iI/AAAAAAAAEds/tuW8q8kisgE/s1600/Great+Mullein+04.jpg

I also found on a highly biased and unreliable site, herbcraft.org, the flower oil from mullein can treat ear infections, remove excess wax from ears, clean infected piercings, treat ear mites in animals, used as an antiseptic, can stop swelling when combined with garlic oil, and when ground ivy is added to it the combo can cure Meniere's disease..  

Growth

V. Thapsus is a biennial. The plant grows its leaves out wide and the roots thick and deep the first year. The second year the plant uses the stored energy from the previous year to grow tall and produce flowers and thereby seeds.

The plant has no secondary growth.
There are no growth rings because the leaves (Which makes up the entirety of the above ground portion of the plant) die with the frost, and is completely regrown each spring. That is why the plant stores it's provision of energy where the frost cannot steal it - in the roots. No newly grown foliage lasts to the next year.

Because of this growth pattern and looking at the picture I posted on the last blog, that the plant has a basal meristem that exists just below/at ground level that produces the next years foliage.

First year growth:

http://4.bp.blogspot.com/-jR679MFCd8w/TbIuG8VI4pI/AAAAAAAADlI/AuEenOIlIVI/s1600/mullein%2B1.JPG

Second year growth:


http://www.ifa.hawaii.edu/info/vis/uploads/images/flora_fauna/mullein.jpg

I could not find any information on secondary growth in the roots, or if the roots die after the two years.

Roots

I feel I covered a lot of root describing in the last post. I shall sum it up. 

The plant is a prairie plant. Prairies are low in water. The plants must have long roots to access the deep water tables. V. Thapsus is one of those plants with long, deep roots. No body has been able to measure the length of the tap root. The most people usually get is a couple feet down before they get impatient and snap it off. Here is a picture of V. Thapsus' tap root. As seen it is thick. 

On a side note you can see that the plant has it's growth center not above ground, but under/at ground level.  (Like the quiescent center but for the upward growth)This helps when a forest fire of herbivores eat/destroy the top of the plant. The V. Thapsus is able to regenerate new leaves quickly and is able to continue photosynthesizing. The stem on the plant is very small and the leaves are the main mass of the plant. 

This plant does have lateral roots, although they are not as main as the tap root. There are significantly less lateral roots.  

As for mycorrhize, I have not found any information. I looked at several different web sites which all talk about germinating and planing this plant, and they don't say anything about making sure there is the right species of mycorrhize. Their plants do well. I would assume that this means the plant uses a generic species of mycorrhize that can be found in the prairies. Most likely an arbuscular mycorrhize The mycorrhize would help with lack of lateral roots. The fungi would help the plants have enough nutrients, and in turn the plants would give the mycorrhize carbon or sugars or what ever it would need. The fungi would also help in collecting rain water and delivering it to the plant. 

Water Issues of Mullein

Water is factor is V. Thapsus. The plant has adapted for it by creating a deep root system that in the first year is significantly larger than the plant mass above ground. The first year of this plant the root system is the main priority, the leaves stay flat and spread out horizontally. The second year the storage in the roots is used to grow the plant up  wards and to produce flowers. The tap root is shown in the below picture.

The leaves are also adapted for reducing water loss. The leaves are hairy which, as we learned in class reduce airflow over the stomata, this decreases the water evaporation. The plant's petiole is relatively thick, and hairy as well. The thickness is due to large xylem and vascular tissues to transport the water to the leaves for evaporation. They are hairy to avoid excess evaporation with respirating. The entire plant is very well adapted for the low moisture of the prairie.

The light color of the hairs reflects light, keeping the plant cool t also prevent excess water loss.

Leaves

http://fireflyforest.net/images/firefly/2005/July/Verbascum-thapsus-2.jpg

Through my own observations I've found that the leaves are fuzzy, having light colored hairs on the leaves. This helps prevent the leaves from drying out as well as assisting in keeping herbivores away. The leaves are large, and relatively smooth on the edges. The underside is not nearly as hairy as the top. It is still fuzzy however. The leaves are relatively thick with all the hair. The leaves as shown in the picture above spiral around the stock this is during the plants second - and last year. During the first year of this plant the plant is low to the ground, but still has that spiraling structure. The leaves on the bottom of the plant are larger in both width and length. The size tapers to allow light to hit those lower plants. Self-shading is a big issue for this plant, and this is the strategy it utilizes to overcome that issue.

The leaves are the most identifying structure on this plant, after which are the flowers. All that I have mentioned above I have self observed looking at these pictures posted here and through my own experience among them.

http://www.missouriplants.com/Yellowalt/Verbascum_thaspus_leaf2.jpg

Some things I found out about the plants are some of the medicinal uses of the leaves. I cannot vouch for these herbal remedies, botanical.com says people do this.

"The dried leaves are sometimes smoked in an ordinary tobacco pipe to relieve the irritation of the respiratory mucus membranes, and will completely control, it is said, the hacking cough of consumption. They can be employed with equal benefit when made into cigarettes, for asthma and spasmodic coughs in general" 

(http://www.botanical.com/botanical/mgmh/m/mulgre63.html#med).

I personally doubt adding smoke to your lungs - no matter the plant- would not be beneficial to your health. I will not be trying this method of healing a hacking cough.

Try it if you dare.