Maturity and Plant Reproduction
Location: Outside U.S.
Country: Trinidad and Tobago
Date: Summer 2011
I was told that a plant does not need to be mature in
order to produce. If this is true then explain how can it reproduce
if it is not mature?
In fact, plants DO need to be "ready" before they are able to reproduce. For flowering plants, this means they need to be able to produce flowers, and any seed that develops from the flower, inside a fruit of some kind, needs to be able to fully ripen and mature. Seeds from that mature fruit need to be "viable", that means "alive" and able to start the plant's life cycle once again.
One example is an apple tree. An apple tree might grow for several years before it produces flowers. The apple tree flower is the way the apple reproduces. If there are no flowers, no apples will be produced, and no seeds will be produced, for that year. Sometimes it takes 5 years of growth before the apple tree will produce its first flowers. When flowers ARE produced, and if the flowers are successfully fertilized, typically by insects or wind-blowing of pollen, the flower will produce seeds encased inside what we call an apple.
Sometimes people will take cuttings of branches from apple trees that have already produced flowers, and they will use chemicals or other artificial means to get those branches to produce roots. Such a method could have a very small (by not very young) new "tree" produce flowers and fruit. It is important to remember, though, that the branch is already old enough to produce flowers.
Different plants have different time requirements for reproduction. Some plants live only 1 year, so they need to quickly mature and reproduce before they die. Others live several or many years, and there is more time for the maturation to occur. Again, different plants will be able to reproduce at different ages, depending usually upon what is natural for that plant.
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I think your main problem here is understanding the term 'mature'
In many animals, we consider an individual mature when they have reached their final growth size. For many animals this is necessary before they can reproduce. For many mammals however, including humans, it turns out that they can reproduce before they are mature. You only have to think about 14 year old boys to understand what I am saying.
In the plant kingdom however, the situation is even more complicated. Plants in general do not stop growing - but continue to get larger throughout their lives. It is not possible then to say that a plant is mature when it stops growing - as we can with many animals. Some plants - the annuals that only live above ground for a season and then die - will grow for the first part of their lives. They then almost stop their growth as they put all their energies into flowers and seeds, and then they die. This is not the case with long lived plants such as trees. They can flower and produce seeds hundreds of times in their lifetime. In fact many plants are already producing flowers and seeds well before they are fully grown.
Lab Technician Barkly College - Secondary
Tennant Creek, Northern Territory
When plants bear fruit/seeds they are mature. Many plants also reproduce vegetatively by rhizomes, underground stems, etc. The following may be helpful:
Also, it is possible for scientists to use tissue culture methods to clone/reproduce/multiply plants.
Anthony R. Brach, PhD
Missouri Botanical Garden
Harvard University Herbaria
It depends on the kind of reproduction. Plants can reproduce asexually. Grass produces tillers; strawberries have runners; potato has stolons. All of the structures are ways to reproduce an independent plant that is genetically identical to the parent and can happen before the plant is mature.
I think the confusion stems from the fact that “maturity” comes in two flavors – economic and physiological. A crop does not necessarily have to be physiologically mature to produce (i.e. be harvested and sold at a growth stage with economic value). A distinction needs to be made between “produce” and “reproduce”.
It all depends on what plant part is marketable. For instance, lettuce is optimally harvested and sold in the vegetative stage, well before reaching physiological (reproductive) maturity. A lettuce plant that has gone to seed is typically bitter and unpalatable. The seed stalk also makes it aesthetically unpleasing at the point of sale, even if removed. Bottom line for lettuce: it’s harvested while still physiologically juvenile but economically mature. The flip side would be something like cotton. Cotton bolls are the product of a bloom (the apex of maturity) and would be harvested at the physiologically mature stage. In this case, physiological and economic maturity happen to coincide.
Ultimately, we are the ultimate arbiter of what is mature. Economics always prevails over physiology. Humans have devised a number of maturity indices for different crops, such as: % moisture, size, color, % soluble solids (sugars) % acidity, etc. Some of these are rather arbitrary (qualitative), while others are measurable with instrumentation (quantitative).
Dr. Tim Durham
Instructor, Office of Curriculum and Instruction
Department of Biological Sciences
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Update: June 2012