It's kind of a contradicting article, but let's see what you think.
Whats the big deal with carbohydrate and amino acid productsthem these days? Are they being used or misused by growers? We asked Steve Berlow, a research consultant for Florigen Laboratories in BC, Canada to give us his insider perspective on the rise of carbohydrate and amino acid based products in the marketplace in recent years…
So a grower walks into their local store, decides to buy a big bottle of some sugary carb supplement, with the intention of deploying it on his next res change. The notion is that the plants will suck up the carbs and get a boost of ‘pure energy’ without having to go through the hassle of producing them as a product of photosynthesis.
Errrr, sorry to spoil the big carb party, but it’s not actually that straight forward. The carbohydrate supplement is definitely a case where theory got ahead of practice. In theory providing your plants with an array of simple and complex carbohydrates seems like a great idea. We all know that plants, driven by light energy and photosynthesis, produce sugar and starch. The plant uses this for growth and development. So the theory goes – if we supplement our nutrient solution with those very same sugars and starches, then the plant won’t have to make them all for itself and can therefore devote its energy to other things – such as making big flowers and fruits! Alternatively, if the plant is undergoing a period of physical stress (such as flowering or fruiting) then the supplementation of those sugars and starches will enable the plant to grow and develop at warp speed as we have removed a limiting factor. Unfortunately all this seems feasible in a text book but, as usual, these things are rarely as simple in real life.
Why not? Well, put simply, it’s one thing to supplement a plant with carbs in a lab, quite another to do so in vivo (real life – real situation.) You can inject carbs directly into a stem or a leaf, for instance, using laboratory techniques, but surely the crunch question is: can a plant uptake carbohydrates through its roots? I have been involved in research that aimed to determine whether plants could actually uptake and utilize carbohydrates and, if so, what could they uptake and utilize. Carbohydrates range in size from very small, simple structures like glucose or fructose through to enormously large, complex molecules like polysaccharides. So – did I find that plants could uptake simple and complex carbohydrates? Other than some very simple, and small carbohydrates (e.g. plain table sugar or fructose / glucose) plants essentially cannot take up other more complex carbohydrates through their root zone. Why? It’s because of a unique little barrier in the roots called the Casparian strip – complete with his sidekick the endodermis. Essentially the Casparian strip forces everything, and that includes carbohydrates, through the endodermis to be actively selected or rejected for uptake.
Ready For The Science Bit? Introducing The Casparian Strip – Your Plant’s Very Own Homeland Security!
Inside the roots of your plants sits a very innocuous and extremely important band of cells – called the Casparian Strip. I like to think of this as a sort of “security guard” for your plant. It is used to block the passive flow of materials ( travelling between the cells), such as water and solutes into the main water carrying columns of the plant – the xylem and phloem. By doing this it forces everything to actively pass through or be rejected by the endodermis. Once within the epidermis, water passes through the cortex, mainly traveling between the cells. However, in order to enter the stele, it must pass through the cytoplasm of the cells of the endodermis. Once within the stele, water is free again to move between cells as well as through them. For solutes to pass through the endodermis they must be in inorganic, ionic form to be transported across to the stele. As you can see getting water and nutrients inside your plants is no easy process!
An interesting side note for people who grow with organic nutrients.
When you hear of the virtues of organic fertilizers, remember that such materials are unable to meet any nutritional needs of the plant until they have been degraded / converted into inorganic forms. Organic matter does play an important role in making good soil texture and rhizosphere health, but it can only meet the nutritional needs of the plant to the extent that it can yield inorganic ions. Once within the epidermis, only the inorganic ions pass inward from cell to cell.
