# Runner bean spiral growth **URL:** \ **Category:** Factual Questions\ **Created:** [August 2, 2001, 9:55pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701 "2001-08-02T21:55:49Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 2, 2001, 9:55pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/1 "2001-08-02T21:55:49Z")
I’ve just been down to my allotment and picked some runner beans (just in case 'runner bean means something else where you are, I’m talking about [this](http://www.dulley.com/plant/a099.shtml)) I noticed that the plants are twining around/up the canes in an anticlockwise direction, the reverse of what I would expect if the twining was simply a case of the motile shoot following the sun, but then I think that runner beans originate in the southern hemisphere. Is this right? do (native)nothern-hemisphere climbers tend to twine in a clockwise direction and vice versa? ---
**Author:** ![Shiva](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shiva](https://boards.straightdope.com/u/Shiva)\ **Post date:** [August 2, 2001, 10:21pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/2 "2001-08-02T22:21:30Z")
I don’t think hemisphere of origin matters. I’ve seen spiraling tendrils on grapes reverse their twist mid-growth. Here are some sites you may find interesting: [http://www.bookrags.com/books/drwnm/PART20.htm](http://www.bookrags.com/books/drwnm/PART20.htm) [http://iubio.bio.indiana.edu/R10247-11630-/news/bionet/plants/9307.newsm](http://iubio.bio.indiana.edu/R10247-11630-/news/bionet/plants/9307.newsm) [http://www.rrz.uni-hamburg.de/biologie/b\_online/e32/32e.htm](http://www.rrz.uni-hamburg.de/biologie/b_online/e32/32e.htm) Try ‘training’ a shoot in the opposite direction and see what happens. I know what runner beans are but what does anti-clockwise mean? 😉 ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 2, 2001, 10:32pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/3 "2001-08-02T22:32:52Z")
I have tried training shoots in the wrong direction; they tend to either revert to twining in an anticlockwise direction, or they actually ‘unwind’ themselves and fall off the cane. BTW, we’re talking about a row of maybe 100 plants of a mixture of three varieties and **every one** is twining this way, so I think there’s obviously something going on… I’m asking because I remember seeing time-lapse films of growing plants and the growing points always seem to follow the sun (gyrating in a clockwise pattern in the nothern hemisphere) - I’d always thought that this would _automatically_ prejudice climbing plants to a clockwise spiral path, but (with runner beans at least) this is not the case; made me wonder of the behaviour became ‘built-in’ at some point. ---
**Author:** ![Shiva](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shiva](https://boards.straightdope.com/u/Shiva)\ **Post date:** [August 2, 2001, 11:26pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/4 "2001-08-02T23:26:18Z")
From: [http://iubio.bio.indiana.edu/R511058-514242-/news/bionet/plants/9612.newsm](http://iubio.bio.indiana.edu/R511058-514242-/news/bionet/plants/9612.newsm) > [@](#): > > Nonsense - the Coriolis effect has nothing to do with it. Looking at some > plants helps: Hop (_Humulus lupulus_) goes clockwise, and the Kidney bean > (_Phaseolus vulgaris_) counterclockwise - wherever you grow them. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 3, 2001, 8:26am UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/5 "2001-08-03T08:26:17Z")
> [@](#): > > \*Originally posted by Shiva \* > \*\*From: [http://iubio.bio.indiana.edu/R511058-514242-/news/bionet/plants/9612.newsm](http://iubio.bio.indiana.edu/R511058-514242-/news/bionet/plants/9612.newsm) > > > [@](#): > > > > Nonsense - the Coriolis effect has nothing to do with it. Looking at some > > plants helps: Hop (_Humulus lupulus_) goes clockwise, and the Kidney bean > > (_Phaseolus vulgaris_) counterclockwise - wherever you grow them. > > \*\* I’m not talking about the coriolis effect, which is all about **forces** caused by the rotattion of the earth, I’m talking about the [apparent]motion of the sun across the sky. Interestingly Hops (Humulus Lupulus), which twine clockwise) are native to the northern hemisphere, kidney beans, which are native to the southern hemisphere twine anticlockwise. So far, this supports my hypothesis. The article that you posted mentions Darwin’s experiments with climbers which didn’t have a preference for twining direction, for the purposes of this discussion, I feel we must exclude species which show no definite and consistent behaviour and confine ourselves to those which always twine in the same direction. (I now shan’t be too surprised if I learn that some of the plants with no preference for twining direction originate in the tropics) Now the article says that kidney beans always twine anti-clockwise, wherever grown, and this is my initial observation (I am growing them in the northern hemisphere) My question really is whether the twining behaviour of climbing plants _might_ originally have been a simple case of the growing shoot tracking the sun, but over time, the twining direction became inherited, rather than simply behavioural (I’m not suggesting that something got ‘written back’ to the plant’s genome - there are a couple of threads going about this subject already - I’m suggesting that maybe the plants that (through some mutation or other) inherently twined in the direction that follows the sun _might_ have some advantage over their cousins that don’t. ---
**Author:** ![ticker](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@ticker](https://boards.straightdope.com/u/ticker)\ **Post date:** [August 3, 2001, 1:54pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/6 "2001-08-03T13:54:38Z")
IIRC from my biology classes, oh so many years ago, plants exhibit _tropic_ and _nastic_ responses. A tropic response is one which relates to the direction of some stimuli such as _phototropism_ where the plant grows towards a light source. What you describe with the bean plants is however a nastic response and does not relate to the directionality of any stimuli. They grow like that to wind around any supporting structure, not to catch more light. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 3, 2001, 1:59pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/7 "2001-08-03T13:59:54Z")
I know it’s not a tropic response **now** (that much is clear because they still twine anticlockwise here in the nothern hemisphere). I’m asking if it might have been derived from a tropic response at some point a long time ago. ---
**Author:** ![ticker](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@ticker](https://boards.straightdope.com/u/ticker)\ **Post date:** [August 3, 2001, 2:05pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/8 "2001-08-03T14:05:20Z")
Would that not be a bit Lamarkian? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 3, 2001, 3:19pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/9 "2001-08-03T15:19:43Z")
Not at all: > [@](#): > > _Originall posted by Mangetout_ > **My question really is whether the twining behaviour of climbing plants might originally have been a simple case of the growing shoot tracking the sun, but over time, the twining direction became inherited, rather than simply behavioural (I’m not suggesting that something got ‘written back’ to the plant’s genome - there are a couple of threads going about this subject already - I’m suggesting that maybe the plants that (through some mutation or other) inherently twined in the direction that follows the sun might have some advantage over their cousins that don’t.** ---
**Author:** ![ticker](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@ticker](https://boards.straightdope.com/u/ticker)\ **Post date:** [August 3, 2001, 3:55pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/10 "2001-08-03T15:55:56Z")
> [@](#): > > \*\* but over time, the twining direction became inherited, rather than simply behavioural\*\* Like I said, is that not a bit Lamarkian? ---
**Author:** ![Shiva](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shiva](https://boards.straightdope.com/u/Shiva)\ **Post date:** [August 3, 2001, 4:01pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/11 "2001-08-03T16:01:13Z")
Not definitive, but interesting: [http://iubio.bio.indiana.edu/R394390-396222-/news/bionet/plants/9505.newsm](http://iubio.bio.indiana.edu/R394390-396222-/news/bionet/plants/9505.newsm) Anyone keep back issues of Scientific American? And from Darwin again: [http://www.blackmask.com/books17c/cplnt.htm](http://www.blackmask.com/books17c/cplnt.htm) > [@](#): > > The case of another Asclepiadaceous plant, viz., Ceropegia Gardnerii, is worth briefly giving. I allowed the top to grow out almost horizontally to the length of 31 inches; this now consisted of three long internodes, terminated by two short ones. **The whole revolved in a course opposed to the sun** (the reverse of that of the Hop), at rates between 5 hrs. 15 m. and 6 hrs. 45 m. for each revolution. Bolding mine. Ceropegia is a tropical vine with, apparently a marked preference for it’s direction of twining. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 3, 2001, 8:42pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/12 "2001-08-03T20:42:20Z")
> [@](#): > > \*Originally posted by ticker \* > \*\* > > > [@](#): > > > > \*\* but over time, the twining direction became inherited, rather than simply behavioural\*\* > > Like I said, is that not a bit Lamarkian? \*\* NO! - perhaps I should put it this way; suppose there are two populations of closely related twining climbers, both derived from a common ancestor with no particular preference for direction of spiralling, some **completely random** mutation has disposed one population to twine in a direction that follows the sun, the other in the opposite direction (OK, I know that two such mutations at the same time would be unlikely, but stay with me) - suppose twining in the same direction as the sun’s travel confers the tiniest advantage (or twining in the opposite direction confers a tiny disadvantage); the mutant with the advantage is going to win out in the end. but actually that’s not strictly tropic behaviour turning into inherited behaviour I suppose (it’s too easy to look at those time-lapse films of gyrating seedlings and imagine that this is the only possible origin of twining behaviour); I should rework my question, thus; Is there any significant statistical correlation between the direction of twining (of plants that show a marked and consistent preference, despite where they are grown) and their hemisphere of origin? ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [August 3, 2001, 9:03pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/13 "2001-08-03T21:03:20Z")
Twining (or more generally, circumnutation) chirality is indeed genetic. Witness this mutant left-handed Arabidopsis plant. Marinelli, B et al. 1997. A pleiotropic _Arabidopsis thaliana_ mutant with inverted root chirality. Planta 202:196-205. > [@](#): > > Circumnutation is an oscillating movement of a growing plant organ that is believed to result from an endogenous rhythmic process intrinsic to growth. Circumnutating organs, as they extend, describe a helical trace. In Arabidopsis thaliana circumnutation is particularly evident in primary roots and occurs, as in most plants, in a right-handed direction when viewed from above in the direction of the growing tips. A pleiotropic mutant of Arabidopsis with left-handed root circumnutation was discovered and characterized. Major abnormalities of the mutant are: a reduced size of all organs, mainly due to a defect in cell elongation or expansion; a zigzagging pattern of stem pith cells, reminiscent of the erectoides phenotype of the lk mutant of Pisum; and gravitropic roots, which as they grow, form tight, left-handed coils. Genetically, the mutant depends on the presence of two independent monogenic recessive factors acting additively. The mutant alleles of both factors alter the growth of the aerial organs in a similar manner but differ at the root level: one mainly produces non-circumnutating roots, the other changes the direction of circumnutation from right to left hand. The mechanism described by **Mangetout** sound plausible, but I can’t find any data correlating handedness to geography. Note that the abstract says that most plants are right-handed. ---
**Author:** ![Shiva](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shiva](https://boards.straightdope.com/u/Shiva)\ **Post date:** [August 3, 2001, 9:27pm UTC](https://boards.straightdope.com/t/runner-bean-spiral-growth/74701/14 "2001-08-03T21:27:05Z")
Looks like they’re still working on that question: > [@](#): > > Historical factors, such as the possible genetic fixation of growth direction when some twining plants originated in a different hemisphere than the one in which they grow today should also be considered (E. H. Rapoport 1992 pers. comm.). from: [http://www.ots.duke.edu/tropibiojnl/TROPIWEB/BOTANICA/TWINER.HTM](http://www.ots.duke.edu/tropibiojnl/TROPIWEB/BOTANICA/TWINER.HTM)