Just a quick question

[Jerry Sem]

my tank is about 6 weeks old now and well planted. I noticed on one of my Amazom Sword Plants that 2 of the origonal 8 outside leaves have slowly rotted (couldn't find a better word) and had to be snipped off. About a week apart. The other 6 outside leaves are as healthy as can be, the inside leaves are good also. There are 4-5 new leaves growing from the center, all good there too. I dose 2 weekly with Easy Green and have incerted SeaChem Root Tabs as instructed. My substrate is ECO Complete. Is this ok to lose a few outside leaves here and there ?

 

[GaryE]

Yes. Transplanting often does that to plants.

 

[Byron]

I would suggest that the issue is likely the transition from emersed to submersed growth. Echinodorus plants (sword plants are in the genus Echinodorus) are marsh or bog plants botanically speaking, and many species in South America spend half of the year in water, but the other half (the dry season) as terrestrial plants. Nurseries grow the plants in the emersed stage, the roots in wet substrate but the leaves develop in air, because it is easier to fertilize them and they develop faster which lowers the cost to the nursery. The plant produces different leaves depending upon the environment, meaning either in the air or under water. So the plants the nursery sells to fish stores will have been grown emersed and thus have thicker and stronger leaves. If you then plant them in an aquarium where they are submersed, the plant knows and will produce submersed leaves from the centre of the crown. As this occurs, the plant will use the nutrients in the older leaves to help grow the new leaves, and the older outer leaves will slowly die.

Don't be quick to remove the outer leaves when you see them yellowing. It may not look aesthetically nice. but the plant is using certain of the nutrients by moving them from the old leaf to the new leaves. These nutrients are referred to as mobile nutrients. They are nitrogen, phosphorus and potassium; potassium especially is very mobile. Two micronutrients are also mobile, chlorine and nickel. Obviously as the plant moves these nutrients, the leaves show the deficiency. I always left the outer leaves until the base of the stem at the crown is brown; once this occurs, the plant can no longer transfer nutrients because all the veins are broken, and you can remove the leaf. Echinodorus plants are extremely adept at doing this. They really are wonderful plants for the aquarium, in my opinion anyway.