Not enough water, or too much?

For maybe two weeks now three of the Baobab seedlings have been looking, to varying degrees, a bit under the weather. As you can see from the picture, some of the leaves have gone yellow, and are very soft and floppy. The rest of the plant has also stopped growing.

Now yellow leaves usually mean that something's wrong in the water department; either the plant is getting too much, or not enough. The only thing that has happened in the past couple of weeks water wise was that Morag, who is in the office all week and looks after the watering, was off on leave for a week. Now as we know, our seedlings are dryland plants, and so one might think that they would manage ok with missing a watering. The thing that is more strange is that only these three plants have been affected, whilst there are the five healthy Baobabs that I potted up last week, and two of the delicate looking Neems still going strong.

Two of the seedlings do look pretty much past saving, but the third might be salvageable. It'll be a case now of making sure that these do get enough water, seen as that seems to be the most likely thing to have changed, which could either be the kill or cure. What's really interesting to me is that plants that are ultimately treated in the same way have different success rates - a fantastic example of the 'survival of the fittest' principle and evolution in constant progress!

Bigger Baobabs and Blue Peter pots

It's been a good few weeks since the last repotting of the Baobabs, and they've been growing well, doubling in size really. Having seen last time that the roots went so deep relative to the height of the plant I thought it was time to give them a bit more space again.

Based on the roots I needed to make sure that the depth of the pot was prioritised over the width. Now very tall and narrow pots do exist, but they're not easy to find and not necessarily worth the outlay. Especially when people have wonderful ideas for reusing day to day items instead! The environmentally and financially considered idea of using empty juice and milk cartons seemed like the best and most colourful way forward.

After cutting the very tops off the cartons (carefully!) I made five holes in the bottom - just big enough to push a pea through. This round of repotting showed that the roots hadn't grown as much as I might have expected, and were just a bit longer than they had been before, and are now only half the size of the rest of the plant. There were also far more lateral roots, although they're very delicate and short.

I think the cartons look quite good in their different colours, and the Baobabs themselves are looking quite good too really, with new leaf growth. The Neems are doing well with leaf growth too, and I think look really pretty with their feathery leaves. We'll see how they go in the next few weeks, and maybe get them out in the sunshine!

On the importance of leaves

As promised last week I've done some looking into leaves, why they are different across diferent types of trees and plants, and what makes our Baobab and Neem leaves specially adapted to the hot dry conditions of countries like Burkina Faso and Ghana.

It would seem that something sticks in the mind from school days biology, as most of us know that the most important thing a leaf does is produce food for the rest of the tree through the process of photosynthesis. Importantly for us, in this they also produce oxygen and use up carbon dioxide. For plants like Neems, their leaves shown below, it's also important to know that because leaves have a large surface area for maximum reciept of carbon dioxide and sunlight, they also lose water through a process called transpiration.

For trees growing in drylands Africa, water is hard to come by and much of the year is spent with very little rainfall, whereas there is plenty of sunlight. This means that the leaves can generate lots of food, but also risk losing a lot of water. One thing that trees in such areas can do is lose their leaves during the dry season, which means that trees such as the Baobab can avoid losing too much precious water through transpiration. The leaves can also be shaped in a way to take advantage of all that sunshine, and so are flat and thin, unlike say pine needles.

Leaves are the food factories for our Baobab and Neem seedlings, but they can be used as food for people too. As we say at TREE AID, 'not just a tree'. I've got lots of fascinating facts on the things that people in Africa use our Baobabs and Neems for when they grow to full size in the wild, and will blog about them soon!

Neems!

Having been away for about a week I've come back to lots of fresh growth on the Baobabs and, more excitingly, two Neem germinations! This is really good stuff, as we hadn't seen any signs of life amongst so much Baobab activity, and I had been beginning to loose hope that any might germinate.

The two Neem seedlings have germinated in pots marked 1 and 3, which would suggest that they are equally happy being soaked for 24 hours, or 15 minutes prior to sowing, or in fact anything in between. They've also gone from seeds to seedlings with a full set of 'true' leaves and another one on the way in what feels like quite a short space of time, certainly relative to the Baobabs anyway.

As you can see, the Neems have very different leaves to the Baobabs. Rather than having large, oval leaves with their pointed tips and smooth edges, they have three or four smaller, serrated leaves branching from a central point to make up a more feathery looking leaf. Also, whereas the cotyledon and 'true' leaves of the Baobab looked quite similar in the end, the difference between the two on the Neem could hardly be greater. The cotyledon leaves look very much like half a green peanut; small, thick, and with none of the serration or featheriness that you can see in their 'true' leaves.

I'm intrigued as to why the leaves of the two plants are so different. Tony Hill, our Programmes Director and general tree knowledge man, says that even young leaves that aren't cotyledons can look quite different to adult leaves, and so the Neem leaves will end up being larger and a bit more sturdy. It will be interesting to see if I can find out how these leaves are best adapted and suited to the conditions of drylands Africa.

Almost a forest

I haven't been disappointed - in the last week another two Baobabs have germinated, and one pot in particular is looking rather densely canopied!

One seedling has arrived in one of the pots marked '3' in the propagator, and I found the seed case actually lying on top of the soil next to it. When the seeds sprout it seems that they put down a root, and then push up the stalk with the cotyledon leaves and the seed case still around them, which is shed as they unfurl.

Most of the action however is still in the pot marked '2' that the first seedling germinated in. Four out of the five seeds I planted in the pot have now germinated, and the big cotyledon leaves are making it look quite crowded. In a couple of the seedlings you can just see the first pair of 'true' leaves, which is quite exciting. They are quite hard to photograph at such close range, so I've done a sketch to try and give a clearer picture of what's going on.

I think the next task will be to separate out the seedlings in this pot. As dryland trees I would imagine their roots will go down, rather than out, to search out the deep water reserves that they would survive from in the desert plains of Africa. So whilst I'm not too worried about their roots becoming tightly tangled together at this stage, I am interested to see how deep they are relative to the height of the seedline, and to make sure they have enough room to keep going!

More shoots, and leaves too!

It's been about another week, and there are three more shoots, and the first one has leaves now. The new shoots are both Baobabs as far as I can tell, and two are in the same pot as the first shoot, but surprise surprise, the other one has germinated outside of the propagator.

When I planted the seeds I ended up with ten pots in all, only eight of which would fit in the propagator, so I left two just out on the windowsill to see how they'd get on. This new shoot is also from the batch that was soaked for the longest; that is about 24 hours. So I wasn't necessarily expecting one of them to have germinated so soon, if at all - especially seen as the building certainly isn't over heated. Perhaps the heat from the sun in the past week has been enough to keep the soil temperature suitably high.

It's also really interesting seeing the first leaves of the Baobab shoot, which are called cotyledons. The cotyledons are not 'true' leaves, but are formed from part of the seed of the plant. This means that they often look quite different from the leaves that develop afterwards, and can cause havoc in pots and gardens when it comes to identifying intended seedlings and weed seedlings, and knowing which to remove! The Baobab shoot has two of these 'leaves', each about the sixe of a two pence piece, which means they are called dicotyledenous.

Still no news on the Neem seeds then, but really good progress with the Boababs; good to be seeing leaves, and watching how they're developing. It is certainly a learning curve, a return to basic biology, and after the last two weeks I'm expecting big things over the next one!