Discoveries from the natural world
Nandini Dholepat
After our last meeting, during which we had talked about ferns and fungi, the children started posting photos of different types of ferns they came across in our Backyard Discovery WhatsApp group. Their observation had improved. They noticed the different types of leaves, branching structures, and sporangium.
Sujatha saw a photograph I posted and asked, “Did you see the tip? Why is it folding like a question mark?”
“This is Dhekiasaag fern. In ferns, leaves with long stalks are called ‘fronds’. The curling of the frond is called ‘circinate vernation’. A tightly coiled growing tip protects the tender leaves. The structure resembles the head of the violin. So it is also called ‘fiddlehead’. Excellent observation dear,” I replied in the group.
“Ferns are also used as vegetables?”Anand asked.
I replied that some ferns are used to make curries, Dhekiasaag, for instance, is commonly used in hilly regions as a vegetable. It helps ease bowel movements. It is tasty too. But, you should be careful about eating ferns as some of them have sharp needle-like outgrowths called ‘trichome’, which cause an allergy when you touch them.”
“Why do they possess such trichomes?” Vivan asked.
“It is a defence mechanism to survive from herbivores, and they also help reduce water loss from the surface,” I replied.
Madhavi posted a picture with a riddle, “I am not date or coconut, who am I?”
While the other group members posted surprise emojis in response, I said, “This is cycas. It belongs to the non-flowering ‘gymnosperm’ group and is similar to a pine tree. We can see big naked seeds on this tree.”
“Oh! But pine and cycas look very different from each other,” Rini wrote.
“Pine trees are generally found in cold regions. Their long needle-like leaves help to withstand extreme cold. Cycas trees are found in rainforests and semi-dry forests. The thick cuticle prevents water loss. The pine and cycas have adapted to different environmental conditions,” I wrote.
“Variations help to adjust to local conditions,” Anand commented.
“Let’s meet this Saturday in my house,” Madhavi messaged. Everyone agreed.
The next weekend everyone gathered at Madhavi’s house. She offered us some halva.
“It is tasty, texture is also good,” Sujatha said.
“This is made from China grass and milk,” Madhavi replied.
“China grass? What is that? Can you show me?” Sujatha asked.
Madhavi brought out a packet to show. “See this is light and transparent. Available in grocery stores.”
“On the label, it is written ‘agar agar’, 100% vegetarian, carbohydrate, fiber, calcium, iron, and many other things,” Shilpa read aloud.
“Yes, agar agar is a seaweed. It is a kind of algae. It is also used to make the jelly in ice creams,” I said.
“I like the coloured jelly with ice cream,” Rini screamed.
“I never knew this. So, agar-agar is a plant-based food,” Sujatha said.
“Shalini and I found a few more such items in the market. We got this ‘Kallu huvu’ from the spice store. The shopkeeper told us that it is used in the preparation of ‘pulav’ and ‘biryani’. This looks like it was picked recently. You can see a few green pieces and also the tree bark on which it grew.” Madhavi pointed.
“Good job. What else have you discovered?” I asked.
“Look, this is a traditionally made ‘yeast cake’, we can use a small quantity of this when baking, or add it to dosa or idli batter especially in winter when it takes longer to rise. Yeast helps speed up the process of fermentation,” said Madhavi enthusiastically.
“We got some green medicine also, see this bottle. The shopkeeper recommended this too. He said these tablets are good for health. This is also pure vegetarian. We bought this to give it to grandmother as she feels tired often,” Shalini showed the green tablets.
“What is this? How do you believe all this?” Sujatha asked.
I took the bottle to read the label. “This is made from spirulina, again it is an algae. It is microscopic and looks like a spring, so it is called spirulina. It grows in water. It has blue-green pigments, which help in photosynthesis. Let’s check this on the internet.”
Anand opened pages on spirulina and started reading. “It is highly nutritious. Many micro and macronutrients, high protein, etc. Astronauts also carry spirulina.”
“It is a dietary supplement, not a medicine,” I said.
“This is popular. Spirulina juice, laddu, oh! someone has called the laddu ‘green bomb’, so funny,” Anand laughed.
“Where does it grow? How is it collected?” Rini asked.
“Spirulina is cultivated in large tanks so that it can be harvested regularly, dried, and supplied to manufacturing units. You can also try growing it in an aquarium,” I replied.
“Can we use these tablets to grow some spirulina at home?” Rini asked.
“Dear, this is processed. You need live cells. We can get pure culture to grow spirulina from Central Food Technological Research Institute (CFTRI), Mysuru, or any other such centers,” I said.
“What other such plants are cultivated for commercial use?” Madhavi asked.
“Azolla is also grown commercially. It is a fern, a small plant floating on water. It is used as a biofertilizer and animal feed. There is an interesting fact here. Do you remember what I told you about two different organisms living together?” I asked.
“I remember. It is symbiosis,” Anand replied.
“Azolla leaves float on water with freely hanging roots. They double their biomass within two days. ‘Anabaena’ is a blue-green algae that lives with Azolla and helps to fix atmospheric nitrogen. That is how Azolla is used as a biofertilizer,” I explained.
“How to see the green algae attached to Azolla?” Vivan asked.
“If we cut the thin section of the leaf, we can see it under a microscope,” I said.
“I know, nitrogen, phosphorus, and potassium (NPK) are very important for plant growth. We got a packet of fertilizer too. I saw Azospirillum written on it. Is it a combination of Azolla and spirulina?” Madhavi asked.
“Azospirillum is bacteria. It helps fix the atmospheric nitrogen. That’s why it is recommended to mix with soil to grow plants,” I replied.
“Can we see the bacteria attached to plant roots in the lab?” Vivan asked.
“Yes, you can. Similarly, cycas tree roots are also associated with Anabaena. These roots are called ‘coralloid’ roots,” I said.
“There are a lot of symbiotic relationships in Nature. We are all living in symbiotic relations, helping each other and enjoying every weekend with our discoveries,” Anand stated.
“This is what we learn from Nature,” Madhavi added.
“By the way, I got a call from Prof. Reshma saying we could coordinate with one of her research scholars, Raja. She said he is pursuing research on lichens in South India. He is the right person to respond to our queries. I messaged Raja to discuss our visit. He asked us to visit him next Sunday so that he can spend time with us. In the first half, we should visit the arboretum and later we can go to the lab. I felt his suggestion was appropriate as the children can see live specimens first and then observe the lab work.”
1. What are the uses of algae?
2. Draw a tree diagram of life forms from simple to complex.
References
https://www.medicalnewstoday.com/articles/324027#metabolism
https://cftri.res.in/technologies/PSP/spi.pdf
The author is a botanist. She has been involved in teaching and research for more than 25 years. Currently, she is involved as a consultant for Intellectual Property Rights with the Karnataka State Council for Science and Technology (KSCST) and is a visiting faculty member at RIWATCH, Roing, Arunachal Pradesh. She can be reached at nandinidholepat@gamil.com.
