Zinc and Plant Growth: What Is The Function Of Zinc?
The importance of zinc in plants is well known. Zinc plays a vital role in many processes, including cell growth, protein synthesis, DNA replication and repair, enzyme activity and regulation and other functions. The primary function of zinc is to serve as a cofactor for enzymes involved in various metabolic reactions. These include amino acid biosynthesis (e.g. methionine synthase), fatty acid biosynthesis (e.g. linoleic acid decarboxylase) and nucleotide biosynthesis (e.g. ribulose bisphosphate carboxylase).
In addition to its roles in these metabolic reactions, zinc is required for several essential biochemical pathways that are not directly related to metabolism. For example, it is necessary for the synthesis of hemoglobin and erythrocytes, which are needed during blood clotting; it is also required for the production of glutathione peroxidases and catalase. Glutathione peroxidases catalyze the oxidation of free radicals such as hydrogen peroxide.
Catalase catalyzes the decomposition of hydrogen peroxide into water and oxygen.
Zinc also plays an important role in signal transduction and gene expression. It is involved in the proper transcription (reading) of DNA to mRNA (messenger RNA), and it is also involved in the translation of mRNA to produce proteins.
Zinc is an essential trace element required by all living organisms, from the simplest bacteria to humans. In plants, its main functions concern growth and development. It is also involved in many metabolic reactions, such as the synthesis of proteins and nucleic acids, and plays an important role in the synthesis of chlorophyll.
Zinc plays a primary role in the absorption of nutrients from the soil and its deficiency can severely hamper a plant’s growth. In animals, zinc is necessary for protein synthesis and helps in the healing of wounds and the production of DNA.
Zinc deficiency can be seen in a number of ways:
Slow growth, especially stunting.
Yellowing of leaves (chlorosis) mainly in the veins.
Distortion and mutations in leaves, stem and roots.
Delay of flowering time.
In animals there is a loss of taste and smell.
Zinc is absorbed into the root tissues and transported to growing areas of the plant such as the stem and leaves, where it is incorporated into certain enzymes, plays a role in protein synthesis and DNA synthesis. It is also stored in the roots, primarily in the clravicles, which are specialized cells that support the epidermis of the roots.
Minerals are vital to plants just like they are to humans. They are both essential for life. However, just like humans, too much of a good thing can be bad.
Zinc is no exception. Zinc can interfere with the uptake of copper in plants. This is why it is important to keep the levels balanced. TOO MUCH ZINC CAN BE AS BAD OR WORSE THAN TOO LITTLE!
Zinc toxicity is probably less common than zinc deficiency, but it still happens sometimes. As with zinc deficiency, the appearance of the plants will let you know if something is wrong.
Zinc Toxicity Symptoms:
Yellowing of leaves (chlorosis) of the bottom half of the plant.
Soft hollow stems that are bumpy and swollen. These are caused by “hollow stem” bacteria.
Itching or burning of the plant at the site of injection when applying fertilizer into the soil. This is caused by phytotoxic reactions to fertilizers containing zinc.
The primary reason that plants require zinc is for proper growth. If there isn’t enough zinc present in the soil, or if the plant cannot take up the zinc due to a disease or other problem, then it may display one or more of the above symptoms. The key thing to remember is that Zinc is a GOOD thing, and is necessary for good healthy growth.
So if you think your plant may not have enough, it probably doesn’t hurt to give it a little extra!
So if you’re wondering where you can get some of this Zinc stuff, well it is probably already in your soil! However, most soil types tend to have less than optimal levels of zinc for plants, so you may need to add it to the soil. It’s also a good idea to check with your supplier if you are unsure about your specific needs.
The most common form of zinc used as a fertilizer is Zinc Sulphate. This is the form of zinc that is most readily taken up by plants. It may also be listed as a Zn (sulfate).
ZnO = Zinc (Oxide) This is another common form of zinc. It’s not water soluble, so it must be used in some sort of gel or liquid medium for plants to be able to take up the nutrient.
Another less common, but still available source of Zinc is in the form of cereal husks. These are the thin outer layers of grain plants that we humans eat, but are usually removed before processing into food for us. They are ground up and sold as a fertilizer.
These are probably the least common, but also the cheapest if you can find a place that sells them in your area.
Zinc Fertilizer Notes:
Zinc is not mobile in plants, so it is not leached by water, or taken up by the roots. It stays in the soil around the roots, so extra zinc doesn’t just wash away.
It is best applied as a soil drench because it is not taken up through the roots like N-P-K.
Zinc Deficiency Symptoms to Watch For:
If you suspect a zinc deficiency, here is a list of signs to watch for:
Yellowing of older leaves (preventing vigor).
Stunted Growth (marijuana).
Reduced leaf size.
Interrupted bud development.
Reduced anthocyanin production (red & purple colours).
Reduced chlorophyll production.
Delayed flowering time.
Zinc toxicity is pretty uncommon. If you feel you need to add more, just make sure not to overdue it!
In sufficiently high concentrations zinc is actually toxic to plant life. Since most plants require only tiny amounts, zinc is generally non-toxic when used in the recommended dosages. Zinc deficiencies are much more common than overdoses.
One important thing to remember about zinc is that it is not very water-soluble, so make sure you apply the zinc sulfate according to the recommendations in the section above. If you do decide to use a water-soluble form of zinc, please note that too high dosages can still be toxic to your plants. In any case, watch your plant for responses after applying the nutrient and adjust the amount you’re using accordingly.
Cal-Mag Plus (also called Cal-Mag Complex) is a mixture of the three most common nutrients: nitrogen(N), potassium(K), and calcium(Ca). These three nutrients are collectively referred to as macronutrients. Because these three are such common elements, you really don’t need to add anything else to your soil or nutrient solution to have healthy plants, as long as you’re giving them everything in relatively equal amounts.
Cal-Mag Plus is often used as a substitute for potassium and calcium in nutrient solutions. While nitrate and sulphate are the most common forms of nitrogen and sulfur, Cal-Mag Plus is usually in the form of potassium nitrate and calcium hydroxide.
Cal-Mag Plus is most easily applied to the soil, but it can also be applied to the plant’s leaves.
Cal-Mag Plus is typically recommended at the rate of 1 tablespoon per gallon of water for soil application, or 1 teaspoon per gallon of water for foliar application.
Remember to adjust these rates according to the nutrient demands of your plants.
While Cal-Mag Plus contains all three macronutrients, it is missing several essential micronutrients. Therefore, using Cal-Mag Plus without any other nutrients will likely eventually lead to a nutrient deficiency.
Cal-Mag Plus is most effective when used in conjunction with Advanced nutrients, especially for flowering.
The Advanced Nutrients line of products includes:
Advanced Nutes Micro (Part A): Good for vegging and early flowering.
Advanced Nutes Macro (Part B): Good for mid to late flowering.
Bloom (Part C): Use during last two weeks of flower.
Micro Plus (Part B): Use anytime, but best after first two weeks of flower.
Thanks for checking out the thread and I hope this helps you take your garden to the next level!
This list is by no means complete, so please feel free to suggest other nutrients that work well.
Edited by KiLL3rK1LL3r, 05 January 2016 – 08:44 PM.