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Ontario, Canada.

A quick observation of this weeks mundane weekly work routine has revealed an interesting quirk. On Monday morning I loaded up my lunch in a plastic bag and off I went to work. In the bag I had placed two nice plump yellow bananas that I would enjoy later on that afternoon. At lunch time I opened the bag to find two blackened bananas that had rippened in the bag beyond the comfort level of keeping your food down.

My question is this. Why did they rippen so fast? Was the bag trapping the rippening gas etheylene? The temperatures were much the same. When I returned home I found the other bananas in much the same condition as in the morning with no advanced stage of rippening at all.

Does it have any pumpkin implication? Maybe? Should all ripenning fruit be removed from an area of actively growing fruit? It may sound silly but is was an indication that the collection of gas in the bag may have been affecting the speed of decay of these two fruit.

12/3/2004 7:23:32 AM

Litchfield N. H. 03052

You got it right, at a grocery store the frist thing done to new bananas is to take off their covers and plastic to let them breath.

12/3/2004 8:22:16 AM

Deer Park, WI

That is exactly right, Russ. I think bananas produce a very large amount of ethylene gas, as do cantaloupe. Trapping a banana inside a bag is the quickest way to banana bread that i know of!

Im sure the same process applies to pumpkins, but i dont think they produce nearly the relative quantities of gas as bananas.

12/3/2004 8:53:51 AM

Indiana

also if they get really cold bananas will blacken

12/3/2004 9:03:13 AM

you are right about the ethylene. you basically trapped the "ripening hormone" around the bananas.
we just learned about this in Hort class. info from my notes:
Once fruit mature and start ripening, they reach a respiration climactic (sudden increase in the respiration rate). ethylene induces the resp. clim. and after that it's a snowball effect. one ripening fruit can basically cause all the fruit around it to ripen too.

commercially this is how they ripen bananas. they don't allow them to ripen on the tree so they expose them to ethylene gas to get them to ripen. i could go on about other uses of ethylene (did you know it induces flowering in the Bromelaid family?) but i won't bore y'all. :-)

12/3/2004 12:26:58 PM

Western NY

ok, has anyone sealed up a pumpkin? i had my big one shipped to hong kong this year. instead of keeping it chilled like it said on the outside of the container, they left it out in the sun for a few too many days. when the carver got there, it was barely carvable, and ended up turning to mush a lot quicker than expected. we shipped a replacement within a few days, and had no problem. the second fruit was still cool when it got there, and was promptly opened and carved.

now, mine was probably heated to 90-100F for a couple days before it was opened. would the decay (and this was mush, not necessarily rot. i was told it didn't stink like the typical rotten pumpkin) have been caused by the gas buildup, or was it just some non-smellly type of rot?

something to ponder.

12/3/2004 12:36:31 PM

Garden

Thats how we ripen avocado, but I had no idea why it works. Never crossed my mind to try it with other fruit. Tomatoes?

12/3/2004 12:41:43 PM

Itzetown City

Brigitte is right

http://www.plant-hormones.info/ethylene.htm

12/3/2004 12:54:41 PM

Ontario, Canada.

Thank you Brigitte, I really would like to understand all about this process....now can the rippening response be delayed in anyway.....so the fruit may continue to grow and not produce etheylene.

12/3/2004 1:03:30 PM

david... works with tomatoes too

lots of things can be done to slow the ripening process. lower oxygen, increase CO2. potassium permanganate absorbs ethylene gas. sometimes in the floral industry they put little bags of it in with cut flowers to they don't go bad as fast.
for storing fruit you want to slow respiration which breaks down carbs, and slow down transpiration which causes water loss (not good when you're going for weight like w/ giant pumpkins). a cool temp will slow these down. high humidity slows down transpiration too. obviously you want to control disease as well.

just my opinion and what i learned from class.

12/3/2004 2:11:33 PM

Garden

Very good info. Guess you've actually been paying attention in those classes :)

12/3/2004 2:26:10 PM

Ljubljana, Slovenia

I think that ethylene in the air is not enough concentrated to affect the ripening of a pumpkin. Hmm, what about the cavity? Maybe the ethylene there accumulates and plays a role? Imagine a high-tech sterile ventilation system into the cavity to lower ethylene accumulation.. Oh yeah, the fat in milk should absorb ethylene too! Lol

Anyway, as far the fruit grows the measures that reduce ethylene production, i.e. lowering the respiration and cooling, are not an option. However, they could be important for a prolonged storage of the fruit.

12/3/2004 2:47:21 PM

Itzetown City

More than 90 percent of Ethylen(C2H4)in the air comes from motor vehicles. Is your patch near a highway with a high travel rate? Than it is probably enough to cause your plant. C2H4 causes premature ripening and flowering, on trees leave fall. And consider there are more other harmful substances near streets with high travel rates. SO2, NOx, O3 and VOC

12/3/2004 3:12:56 PM

[email protected]

Potassium permanganate makes a good fire starter too!

Didn't anyone ever wonder why a fan blowing in the patch help keep splits from going down? It's not just for drying. It dispels the ethylene gas. Thus we should also collect & remove any "other vegetable" fruit that falls from the vine near the patch.

12/3/2004 3:16:49 PM

Ljubljana, Slovenia

So some more info on ethylene:

It is produced in all plant parts when they are ageing or even under stress. So, when there are a lot of ageing leaves in the patch the concentration of ethylene might be high enough to affect fruit ripening.

One more interesting thing about ethylene is that its precursor is synthesized in water logged (oxygen deprived) roots and then transported by the veins to the green parts. There it is converted (oxidized) to ethylene, which then causes all sorts of ageing process.

PS: sometimes I get a feeling that I might be regarded as a smartass. Well, you never know but most of all I am enthusiastic about the physiology of plants. And lucky it is my job too.. so far.. you never know when the pumpkin fever strikes seriously! :-) Jernej

12/3/2004 3:31:38 PM

Long Island,New York

Its simple.....do not put your giant pumpkin in a zip-lock sandwich bag.......G

12/3/2004 5:00:11 PM

Ontario, Canada.

Brigitte, Do you have any info on cytokinins which can delay senescence and promote nutrient uptake. Has anyone tried this?

http://www.esf.edu/efb/course/EFB530/lectures/cytokini.htm

2) cytokinins (together with auxin) may regulate tissue morphogenesis, since the ratio of auxin : cytokinin in tissue culture medium determines root or shoot production

high auxin : cytokinin = root production
intermediate auxin : cytokinin = callus growth
low auxin : cytokinin (high cytokinin) = shoot production
3) cytokinins delay senescence and promote nutrient uptake

application of cytokinin to a leaf on an aging plant can allow that leaf to stay green, while the others yellow and die
cytokinin application to lateral buds can promote their growth
some pathogens produce cytokinins that attract nutrients to that tissue or cause extensive growth of laterals buds (leads to witch's broom)[Rhodococcus fascians]
4) cytokinins promote chloroplast maturation and cell enlargement in leafy cotyledons

cytokinin application promotes development of chloroplasts from etioplasts
sections of leafy cotyledons enlarge when treated with cytokinin (but not acid growth)
Cytokinin receptors

12/3/2004 5:11:54 PM

Garden

Another question-
Is this ethylene transferred to the fruit via the vine, or is it airborn, or both? Basically I'm wondering if dying leaves should be promptly removed or is good air circulation in the patch sufficient to remove this element?

12/3/2004 5:58:43 PM

Cologne / Germany

Since I never stored 2 potential main vine keeper pumpkins side by side in a plastic bag on the patch ethylene related problems never occured...:)

12/3/2004 6:23:16 PM

Ontario, Canada.

Floh, we are talking about proof of continued life here for want of a better term. The plastic bag was only an example of what etheylene can do. The key we are searching for is a delaying mechanisim to halt senesence.

12/3/2004 6:27:06 PM

ENGLAND

10 miles from where i live there is a MASSIVE Warehouse, about the size of 6 Soccer Pitches, where newly imported Green Bananas, and other Green Fruits, are stored and ripened on a supply and demand basis. I have seen large gas tankers going into the warehouse yard and i presume that these tankers may contain the gasses used for the controll of the ripening of the fruits in the warehouse.

12/4/2004 7:20:57 AM

Colorado Hail, CO. Elev. 5,900 FT

Russ;
I've been doing some self education on this since you first brought it up. There is much to learn about how ethylene affects plants. What I cannot seem to find is information about how long the plant "stores" the gas.
Yes....stores.
It has been said the as the plant builds up the gas, it signals the plant that it's existence is in danger, and to hurry its ass up with producing offspring. One would figure then, that the build up within the plant of high ethylene gasses would simply cause the plant to eventually pass away due to "old age". This does not occur though. During the course of the cloning experiments, I've discovered the plants all revert totally back to the initial growing cycles they exhibited when they first were "born". This is why I've even set fruits on cloned plants when they first were brought inside. Late in the winter months, right before spring, its all but impossible to get even a single female on the plant, let alone a fruit set! This must indicate the plant is only "storing" the gasses, and the gas does dissapate from the plant via respiration. If this is not the case, then the plant must transfer it to storage units on the plant ( the fruit areas). Any thoughts on this? If the cloned plants revert back to normal growth patterns, then it is not possible that higher concentrations of ethylene stay throughout the entire plant system.

12/4/2004 2:10:44 PM

Colorado Hail, CO. Elev. 5,900 FT

Too much or too little of anything is bad for any life form, be it humans or plants. Plants require some trace of ethylene gas to be able to set fruits. More amounts are required to ripen fruits. Too much and fruits ripen early or rot. It seems the best practice then is to have a higher amount of decomposing plant wastes in and around newly growing plants in spring, and little to none once the fruit is starting it's bulk growth.
Root rot would then be a huge factor causing fruit splits after heavy puddling rainfall. The plant has an abundance of water to distribute to the fruit, oxygen at root levels is replaced with more hydrogen gas than oxygen {H2O is Two units of hydrogen, one unit of oxygen}, and anerobic bacteria populations increase quickly decomposing roots. The plant has plenty of H2O to give the plant and the fruit, plenty of nitrogen {highly water soluable}, and then weather conditions stimulating high growth. The result = Less roots rather than enlongating roots, which are needed to supply enough minerals to developing plant cells. The excessive nitrogen only speeds up the super fast growth rate. Add in any amount of ethylene gasses produced from
rotting roots, and the plant tries to hard getting through it's life cycle all within a few day period. Throw in plant or fruit cells affected by colder weather which cannot move calcium efficiently and you get.............. KA- BOOM!
This is the closest theory I have to why these things split, rot, or mature too early. It does make sense. Comments? I've really set myself up here, huh? LOL!

12/4/2004 2:11:05 PM

Colorado Hail, CO. Elev. 5,900 FT

Now about ethylene in the fruit... I did an experiment before with a fruit that split open a timy hole into the fruit cavity. I discovered it early in the morning and acted quickly. I took about two or three grams of iodine and pushed it into the cavity, then cut a piece of fruit from a sucker fruit, then "grafted" it into the area where the hole was. The iodine prevented the graft from taking the first time, but I did it again, and the second graft took. This lasted and fruit kept growing until heavy rains and very cold temps caused the fruit to split again. The second time the split wasn't at the location of the first split. It was at a new area, the "repaired" area held together until the split eventually ripped up to that area. Even then, the tissue tore next to the repaired hole and did not tear where the graft was made. I cut the fruit off, and did a quick patch graft job, mainly to keep out bugs. The patch wasn't sterilized or cut to perfection, but it lasted for two weeks. When it began failing, I cut open the fruit to perform the autopsy. Amazingly, there was no signs of decomposing inside at all. The iodine, which becomes airborn once in contact with oxygen, had killed off any airborn pathogens and displaced any oxygen which filtered inside. The result: This fruit was the last one after halloween to be chopped up and put in the compost since it decomposed slower than all the non splitting fruits.
I have not had the luxury of growing another splitter since to test this out more and research more. I was not aware of ethylene gas at the time, and I'm not sure if iodine interacts or counteracts its effects as it does with oxygen, but it's something to look into more.

12/4/2004 2:37:11 PM

Ontario, Canada.

Marc....I Love it. Makes a lot of sense to me. Lets find some studuies the indicate this.

Through in the suberization of those shortened roots and its a wonder the darn things survive until Labour Day. I remember I heard someone say awhile back about reducing water to the roots to "force them to hunt a bit"(BEECHY or WELTY)...

Now we need Steve or Bidgitte to supply us with an anti-aging mixture of synthetic cytokinins and a smidgen of auxins and we have an elixir of growth hormones. A fountain of youth for pumpkins

12/4/2004 2:44:17 PM

Jackson Twp, Ohio

Marc,

What type of iodine did you try crystals or standard pharmacy soultion iodine?

I too tried plugging a fruit, it was moderately successful but i couldn't get the plug to grow on all sides, not enough sap flow.

As for ethylene reduction, i believe that there is a commercially produced PGR that is used in apples to control ripening through ethylene reduction. If i recall the spray is called retain. I looked into it for trying on a few plants but dosing would be problematic at best to determine times frequency and rates of application. I think an ounce or something per acre is needed for apples not very practical on a 1000sq ft pumpkin plant.

Cytokinin and auxin dosage presents an interesting possibility. I do know however that the auxin end of things through unfortunate experience can cause incredible damage. For example 2,4-D a common yard and agricultural weed control can cause damage when plants are exposed to ppm concentrations maybe less. Christy's grandparents sprayed their yard or the field accross the street with 2,4-d and she ended up without any pumpkins that year. This is drift over >100 yards. She had incredibly fast growing healthy plants but the plant couldn't break down the synthetic auxin and therefore couldn't transfer from a growth to a fruiting stage. (initially they showed mutated growth for about a month) She could set fruit but they would abort at about 50lbs or less. Something to be aware of.

I have also noticed that fruit set indoors at the end of the winter seems almost impossible, perhaps there is some ethylene buildup in the plant. I have always blindly attributed that to a lack of light nutrients etc though.

Nick H

12/5/2004 12:08:47 PM