Plant physiology and growth

As all other plants, also lavender does Photosynthesis. It is essential for all plants, algae and certain classes of bacteria to survive. During Photosynthesis, in this case Lavender captures solar energy to make simple sugar molecules. Further, this sugar molecules are used as an energy source for growth and development. Photosynthesis is essential for human survival because it provides food and oxygen.

Figure 1 What is photosynthesis? (eSchooltoday, 2017)

There are different categories of plants we talk about photosynthesis.  There are the C3, C4 and CAM plants. The majority of plants are C3 plants which means that the first compound they for when doing Photosynthesis is a 3 Carbon molecule. The issue with this is, that the plant has to open her stromata to get CO₂ in and O₂ out. While doing this, quite a lot of water is lost to the environment. This can be a big problem for plants in hot regions. Further, the enzyme that traps the CO₂ also reacts with O₂ which leads to a of loss of CO₂ of 50%. If a C3 plant is growing in a mild climate, this won’t affect her negatively (Betts, 2007). C4 plants produce instead of 3 carbon molecules, 4 which means that is does not react with O₂. This means that the plant can be more efficient because the stromata does not have to be opened long. These plants have an advantage in high light, high temperature and low CO₂ regions. Lavender is a C3 plant which is native to the Mediterranean regions. This means that it is losing quite a bit of water when opening the stromata. Further, it is also losing CO₂ because the reaction with O₂ and the responsible enzyme.

Furthermore, lavender is a perennial plant, which means that it lives for more than two years. (National Gardening Association, 2017)

A crop has usually vegetative and reproductive stages. The vegetative stage is usually the period between germination and flowering. In this time, the plant is collecting recourses through photosynthesis. These will be important later during flowering and reproduction. Further, during this period, nutrients are needed to support plant growth. During the reproductive stage, the plant is not growing anymore and is focusing on the production of seeds, flowers and fruits. The reproduction stage can be triggered by different environmental factors like daylength. This is called photoperiod. Lavender is a long day plant which means that it needs a certain amount of long days to flower (Cathy Whitman, 2009).

As all plants, also Lavender needs nitrogen but plants can not take up nitrogen from the air by themselves. Nitrogen from the air gets fixated by symbiotic bacteria in the soil. It is then converted into ammonium which can eventually be absorbed by the plant. Some plants have an advantage because they are nitrogen fixers. They have legume root nodules which can also convert N₂ to ammonium and nitrate because of bacteria called rhizobium. You can see the root nodules in Figure 2. Lavender is not one of these plants, so it depends on the free-living bacteria in the soil. (Unkovich, 2010)  

Figure 2 Clover root nodules from an Oak Tree (Richard, 2015)

If we look at future changes, then we can say that climate change will affect many different crops. The climate will be hotter and drier in many areas. Since lavender is a C3 crop, it will have many disadvantages in hot and dry regions. It will lose water trough evaporation while essential gas exchange at the stroma is happening. Gas exchange is happening in photosynthesis. The plant needs CO₂ and releases oxygen which is essential for humans to survive. 

References

Betts, D. L. (2007). What is the difference between C3 plants and C3 plants. Retrieved from K - Stapte Research and Extension: http://www.midway.k-state.edu/livestock/docs/What%20is%20the%20difference%20between%20C3%20plants%20and%20C4%20plants.pdf

Cathy Whitman, p. (2009). Production Tips for Top Performans. Retrieved from Perennials: http://flor.hrt.msu.edu/assets/Uploads/Lavandulastoechas.pdf

eSchooltoday. (2017). What is photosynthesis? Retrieved from eSchooltoday: http://www.eschooltoday.com/photosynthesis/what-is-photosynthesis.html

National Gardening Association. (2017). What are Perennials? Retrieved from National Gardening Association: https://garden.org/courseweb/perennials/Class1/c1p2.html

Richard. (2015, May). Nitrogen Ficing Clover Nodules. Retrieved from Green Mantle: http://www.green-mantle.com/blog/2015/05/

Unkovich, M. (2010). LEGUMES AND NITROGEN FIXATION. Retrieved from soilquality: https://s3.amazonaws.com/soilquality-production/fact_sheets/87/original/Biol_-_Legumes_and_Nitrogen_Fixation_SA.pdf?1401250204