Fruit & Veg.. Why?

[Ouroboros]

Yesterday I was sowing tomato seeds and came up with a few fundamental questions.. Apologies if they are indeed stupid questions.

 

Firstly, why am I buying seeds? -Surely I could just plant a whole tomato or its fresh seeds? If indeed the seeds do need to be dried before planting, why? Surely this doesn't happen naturally..

 

Secondly, what is the purpose of fruit pulp? -I always presumed that it was to give the seeds the necessary nutrients to start growing (when the fruit has fallen to the ground). I know that some fruit are 'designed' to be eaten so that the seeds travel with a host and is relocated (..along with lots of fertiliser). But surely thats not the case for say.. mangos.

 

Thirdly, how can a seed be dried and then kick start into life several years later? I've heard of seeds (found in Egypt) that will still grow after hundreds (possibly thousands) of years after being dried. I believe some Arthropod eggs share this property?

[vordhosbn]

If you intend to sow the seed, you need to prepare them first. After collecting them, along with some pulp, you must set them aside, so they begin to ferment. When mold is formed, they are ready and you can wash and then dry and store them.

[Moontanman]

Yesterday I was sowing tomato seeds and came up with a few fundamental questions.. Apologies if they are indeed stupid questions.

 

Firstly, why am I buying seeds? -Surely I could just plant a whole tomato or its fresh seeds? If indeed the seeds do need to be dried before planting, why? Surely this doesn't happen naturally..

 

Actually yes this does happen naturally, why would you think it wouldn't? It's important to remember the wild variety of tomatoes is nothing like the plant you are growing in your garden, this plant is totally man made via selective breeding over many years.

 

 

Secondly, what is the purpose of fruit pulp? -I always presumed that it was to give the seeds the necessary nutrients to start growing (when the fruit has fallen to the ground). I know that some fruit are 'designed' to be eaten so that the seeds travel with a host and is relocated (..along with lots of fertiliser). But surely thats not the case for say.. mangos.

 

 

Fruits are all different, most are meant to be eaten along with the seeds and the seeds are later excreted in the animals stool. Often the action of the digestive juices are necessary for the seeds to sprout. It is possible that mangoes were originally eaten by a very large animal like an elephant but it is equally likely the plant has a method of seed dispersal that isn't obvious as being spread in another animals excrement. Some seeds such as lotus seeds depend on being chewed by an animal to break the seeds husk to allow them to sprout.

 

 

Thirdly, how can a seed be dried and then kick start into life several years later? I've heard of seeds (found in Egypt) that will still grow after hundreds (possibly thousands) of years after being dried. I believe some Arthropod eggs share this property?

 

The key is in the husk or shell of the seed or egg, how well this husk protects the seeds or eggs and how much water is necessary to keep the embryo alive. Sometimes the embryo is actually dried completely and absorbs water before it can grow. Brine shrimp eggs would be a good example of this. Many seeds vary widely in how long they can lie dormant and still germinate. I doubt there are many seeds that can survive the 1000's of years mark but the few that can do so due to evolved traits that enhance their ability to survive drought and other hostile weather patterns.

[Ouroboros]

Actually yes this does happen naturally, why would you think it wouldn't?

 

I couldn't imagine seeds would naturally become completely dehydrated. Most climates would oppose this.

So osmosis is responsible for kick starting growth by breaking the seed husk..?

[Moontanman]

I couldn't imagine seeds would naturally become completely dehydrated. Most climates would oppose this.

So osmosis is responsible for kick starting growth by breaking the seed husk..?

 

Again, i have to say that tomatoes that we grow do not resemble wild types very closely at all. Our cultivars of the tomato pretty much depend on humans to spread their seeds. I can say how ever i have seen tomatoes come up after large numbers of tomatoes rotted and eventually dried out on the ground but it was in the late fall and the tomatoes had no chance of survival. Yes i would have to say that absorbing water does help the seed to germinate.

 

http://en.wikipedia.org/wiki/Tomato

[skyhook]

I haven't grown any tomato plant. The last time I buried some fresh seeds with the pulp still covering the seeds, nothing came out of the soil. It seems by getting rid of the pulp and dry it, the seeds have a higher chance of sprouting. but I'll have to try it again.

Mangoes can be eaten and dispersed by fruit bats or flying foxes. Monkeys too. They just don't eat the hard seeds.

[Moontanman]

There are few seeds that will grow out of the fruit that contains them, most require an initial drying at least. Being spread in the excrement of animals is a common method of seed dispersal. Digestive juices allow the husk of the seeds to be penetrated by the embryo. Some fruits with large seeds were at one time undoubtedly spread by larger animals.

 

Swallowing a mango seed would require a rather large animal. I often hunt for dewberry vines in the spring by looking for areas where birds roost. The vines almost always grow under areas where birds rest after eating the berries. Under power lines are a common place for dewberries to grow, one side of the road will be bare but the side under power lines will be over grown with the vines.

[StringJunky]

Some crop seeds and fruit seeds need vernalizing to break their dormancy...they need to be put in a moist medium and chilled for a couple of weeks or so.

 

Just a guess, but I think many Northern Hemisphere seeds have evolved to stay dormant until after a period of frost so they don't start growth in adverse conditions reducing there chances of completing their lifecycle.

[Mr Skeptic]

Firstly, why am I buying seeds? -Surely I could just plant a whole tomato or its fresh seeds? If indeed the seeds do need to be dried before planting, why? Surely this doesn't happen naturally..

 

There's two reasons to buy seeds. One that has been mentioned is that some seeds require certain triggers before they will germinate. Another is that some of the seeds you buy are hybrid seeds. If you know Mendelian genetics, the way it works is the seed suppliers have homogeneous two plants, one AABBCCDD and the other aabbccdd, and they cross those to get heterogeneous offspring that are AaBbCcDd (where the letters stand for two variants of four genes, presumably ones that are important for food production). Heterogeneous organisms are frequently better than the homogeneous ones. However the setup I described uses some homogeneous plants but guarantees heterogeneous seeds. If you let your plants breed, it is very unlikely that you'd get heterogeneous ones, so your seed would be more wild type.

 

Secondly, what is the purpose of fruit pulp? -I always presumed that it was to give the seeds the necessary nutrients to start growing (when the fruit has fallen to the ground). I know that some fruit are 'designed' to be eaten so that the seeds travel with a host and is relocated (..along with lots of fertiliser). But surely thats not the case for say.. mangos.

 

The pulp is not nutritive for the plant; it is a bribe to get us animals to spread their seeds. Plants are perfectly capable of having huge seeds if they want to nourish their young.

 

Thirdly, how can a seed be dried and then kick start into life several years later? I've heard of seeds (found in Egypt) that will still grow after hundreds (possibly thousands) of years after being dried. I believe some Arthropod eggs share this property?

 

The dirty little secret is that "life" and "death" are actually rather poorly defined words. In a dry state, the seeds go into some sort of suspended animation, where they use little or no energy to live but have limited or no self-repair. Fortunately, the seeds components seem to be designed to tolerate dry conditions without breaking or decomposing or receiving much damage.