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Author Topic: Reasons for thorns on citrus plant? Does leaves size relate to fruit size?  (Read 305 times)

lavender87

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  I just wonder are there reasons for those thorns on citrus tree? And it seems like the citrus type with more thorns often have sour or bitter taste than others. So is there a relation between tastes and thorns, or just a coincidence?

  I used to think of a relation of thorns and cold hardiness, but that thought went away quicky because lemon has a lot of thorns but the least cold tolerant while poncirus trifoliata has even more thorns but the most hary.

  Oh, and what about leaves size, is it proportional to fruit size?
« Last Edit: January 03, 2019, 10:37:08 AM by lavender87 »

Millet

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Thorns are actually modified leaves.  The tree uses thorns for protection, and as a good method to distribute rain over the entire tree's root area.  Leaf size to fruit size is a question I have not heard before.  I don't think there is a relationship.  Lemons have larger size leaves but rather normal size fruit.  Finger limes have very small leaves but produce fruit quite large in comparison to the size of the leaves.

lavender87

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  So is there a relation between sourness, bitterness and thorns? Citrangequat has significantly less thorns versus Poncirus and was less sour and less bitter. I am not sure if am I right, I think lemon is the most thorny citrus (excluding trifoliate orange) and is the most acidic in taste. 

  The reason I have this question is I am about to do experiments on citrangequat x meiwa kumquat offspring seedlings. I will try to get rid of those seedling with the most thorns as well as trifoliate leaves because I guess the number of thorns and trifoliate leaves does have a link to sourness and bitterness.

  After eliminating seedling with most thorns and trifoliate leaves, the remnants will be tested for the second round outside in winter to eliminate those would die of freezing. I don't have lot of land to wait too long for those junky seedlings to prove themselves worthy to be kept. It might sound cruel but it's how it is.

Thorns are actually modified leaves.  The tree uses thorns for protection, and as a good method to distribute rain over the entire tree's root area.  Leaf size to fruit size is a question I have not heard before.  I don't think there is a relationship.  Lemons have larger size leaves but rather normal size fruit.  Finger limes have very small leaves but produce fruit quite large in comparison to the size of the leaves.

   By comparing the leaves size, I mean to compare leaves of the same sub-family like orange to orange and lemon to lemon. I have not verified this in citrus but it seemed true in some other type of trees like some lines of persimmon and mango. This might not be true in all cases, but I did see some with large leaves, larger fruits.

   
« Last Edit: January 03, 2019, 06:28:39 PM by lavender87 »

Citradia

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Almost all citrus as well as other fruit tree species will be very thorny as seedlings as a means of protection from wildlife. When the tree reaches maturity in 5 to 10 years, it will produce fewer or no thorns and leaf size and shape can change and then that mature growth higher in tree can also produce flowers. Also, if you leave oneóyear old seedling poncirus hybrids outside through the winter in pots in north GA, they will probably all freeze to death. It would be best to keep potted seedlings indoors or protected from freezing for a few years before trying them outdoors planted in ground in spring after last frost. Poncirus hybrids are not hardy like a crabapple or plum seedling; they are very susceptible to freezing temps and will die. Iíve lost flying dragon seedlings left out in pots over winter.

911311

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Oh really, pocirus seedlings die oout due to freezing? Thank you for the info, now I know why there were very few seedlings around the mature Poncirus trees. Probably most of the  could not make it through a normal winter in northern part of GA.

Citradia

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They will be hardy or hardier if roots in ground but not as hardy in a pot. Maybe better chance in pot in north GA depending on elevation, than where I am in western NC. My main point was that citrangequat or a poncirus hybrid yearling will not be hardy in a pot in zone 7 over winter outside.

911311

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  My unknown 7 month-old lemon seedlings (grown in small plastic pots from lemons fruit bought from store) has amazingly survived the previous 25F for 1 night and continued below 32F for several days after then back to 27F, but they only died back about 1/2 top of the the plants on the end of November 2018. They are still alive healthily with no further damage even when the tempt dropped down to 25 again on Dec-06-2018.

  I could not believed they did not die out completely as I thought they should have because I totally forgot to bring them inside on those freezing days. They did not grow or recover with any new leaf but the trunk look fine with about 4 to 5 healthily green leaves left on each seedling. I left those pots outside at a windy site in my backyard with no protection at all.

  I will take pictures probably tomorrow when have time.
« Last Edit: January 05, 2019, 11:48:40 PM by 911311 »

Citradia

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911311, your seedlings saw barely below freezing temps for a few hours each night so yes they were lucky to survive. Iím guessing the pots were on the ground getting some heat from ground that has not frozen yet. Sometimes wind at night helps prevent frost from settling on plants and sometimes high freezing winds will damage citrus more than if protected from wind. If youíre potted seedlings are allowed to be outside for many hours in sub freezing temps especially if the soil and roots in pot freeze, they will die. Weíve been relatively mild winter this season so far here other than a heavy snow storm in mid December, and have not seen freezing temps here for three weeks now. However, itís supposed to get into the low twenties mid week, so I plan on bringing my potted hardy citrus indoors. Iíve lost a lot of young ďhardyĒ varieties to freezing temps over the years. Your seedlings will not get tall enough to bloom in 5-10 years if they keep loosing height to freeze damage every winter. Real lemons are among the least cold hardy citrus. In Atlanta itís too cold to grow lemons outside without protection. If you want fruit off a tree growing in the ground in Atlanta, Iíd suggest getting a grafted satsuma, Meyer lemon, Ichang lemon, Changsha mandarin, sour orange, grafted on flying dragon rootstock so you can keep them dwarfed enough to cover them and heat them with space heaters when temps get below freezing. Citrus fruits during late fall and winter (November/December) and north GA can freeze in those months meaning your fruit still ripening in trees will be damaged if prolonged freeze, so need to be covered anyway. Folks in south GA and the coastal southeast can get away with protection via microsprinklers or just planting a tree on south side of house, but in our more continental climate, the fruit takes longer to ripen, shorter growing season, and prolonged freezing temps sometimes below freezing for days, we must fully cover citrus to have success with fruit production. There are no commercial citrus groves in Atlanta for a reason; too cold. You might get fruit off of citrumelo or ichangensis or maybe Thomasville or other citranges in Atlanta without more than protection from northern winds, if you harvest in November.

 

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