cloning in the dark

Thursly said:

I may be setting myself up for crap here but..
Don’t you want to stop photosynthesis for rooting?
I hope it works out man I would be thrilled so I don’t have to keep moving these little gals to and fro

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HindukushMaster said:

still lookin SUPER lush and healthy, day 3 or 4.. Ive been lettin the let sit on em maybe a couple hours a day if anything but not much. lets hope this works boys!

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HindukushMaster said:

Possible? Was gonna do an experiment to see if these 4 cuts i have will root in total darkness

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Etiolation occurs when plants are grown in either partial or complete absence of light, and is characterized by long, weak stems; smaller, sparser leaves due to longer internodes; and a pale yellow color (chlorosis). This is a mechanism to increase the likeliness that a plant will reach a light source, often from under leaf litter or underneath shade from competing plants. The growing tips are strongly attracted to light and will elongate towards it.

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

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Much research has been done to explain the action of various treatment methods and it has been reported that etiolation of stems causes anatomical and physiological changes. Lack of chlorophyll, increase of internode length, increased succulence and decreased mechanical strength of stem tissues that generate roots are some of the etiolation effects (Maynard and Bassuk, 1988). Etiolation promotes adventitious root formation on stem cuttings of many wood species (Anderson, 1981; Bassuk et al., 1984). It is well known that the environmental factors which influence the rooting of cuttings include light quality, intensity and duration (Andersen, 1986). Cuttings from etiolated stems usually root better than those obtained from green ones (Magdalene, 1998; Xuebo and Brewbaker, 2006).

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Etiolation reduces total phenolic, anthocyanin, chl a, chl b, carotenoids, carbohydrate contents and antioxidant activity but enhances root formation. Etiolation may be used as effective pretreatment step to improve root formation.

http://www.scialert.net/fulltext/?doi=ajps.2007.839.843

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smokinshogun said:

So all that is pretty much saying my idea is a decent one. By intentionally stretching the branches with Far-red light before taking them as clones they will root faster AND have more stem for roots to form.

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Title: The role of light and polar auxin transport in root regeneration from hypocotyls of tomato seedling cuttings.
Personal Authors: Tyburski, J., Tretyn, A.
Author Affiliation: Department of Biotechnology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100 Torun´, Poland.
Editors: No editors
Document Title: Plant Growth Regulation

Abstract:
A relationship between light conditions, auxin transport and adventitious root formation by hypocotyls of tomato seedling cuttings was demonstrated. Effective rooting of tomato seedling cuttings was observed under continuous white light (WL) irradiation. However, root formation was reduced in darkness or under red (RL) or blue light (BL). At least 3/4-day-long irradiation treatment with (WL) was necessary to increase the number of roots formed in comparison with control cuttings grown in darkness. Light was most effective if applied during the first half of the 13-day-long rooting period. The role of photoreceptor-dependent light perception in the light-regulation of rooting was tested using tomato photomorphogenic mutants: aurea (au) and high pigment (hp). When exposed to WL both mutants generated fewer roots then their isogenic wild type (WT). In darkness or under BL and RL less roots were formed on all plants and no difference was observed between mutants and WT plants. TIBA (2,3,5-triiodobenzoic acid) inhibited rooting in a dose-dependent manner both in darkness and under WL. However, although rooting was suppressed by 0.75 µM TIBA in the dark, 8 µM TIBA was necessary to block root formation in continuous WL. Inhibition of rooting by TIBA was most efficient when applied at the initial period of rooting, a 1-day-long treatment with TIBA being sufficient to suppress rooting if given during the first 2 days of culture. Later treatment had much less effect on the root formation.

http://www.cababstractsplus.org/abstracts/Abstract.aspx?AcNo=20043045097

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Title: Studies on photosynthesis in cuttings during propagation. II. Changes in the rate of apparent photosynthesis in hardwood cuttings of grapevines after planting.

Personal Authors: Ooishi, A., Machida, H., Hosoi, T., Shiobara, Y.
Author Affiliation: Shizuoka University, Shizuoka 422, Japan.
Editors: No editors
Document Title: Journal of the Japanese Society for Horticultural Science

Abstract:
When cuttings of the grapevine cv. Delaware were propagated at 20 deg , 25 deg or 30 deg C, both rooting and shoot growth were better with rising temperature at an early stage of propagation. The change in the rate of apparent photosynthesis, expressed either on a cutting basis or a leaf area basis, was related to root development. At a later stage of propagation rooting was best at 20 deg , followed by 25 deg and 30 deg . The rate of apparent photosynthesis expressed on a cutting basis increased throughout the propagation period at all temperatures. When the cuttings were propagated under different light intensities (provided by shading with 1-3 layers of cheesecloth), both rooting and shoot growth began earlier with the minimum shading, although at the end of the propagation period rooting was best under 2 layers of cheesecloth. Fewer roots were produced in darkness than in light. Changes in the rate of apparent photosynthesis were not always related to root development.

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COMPARISONS OF STOCK PLANT ETIOLATION WITHTRADITIONAL PROPAGATION METHODS
BRIAN K. MAYNARD AND NINA L. BASSUK
Department of Floriculture and Ornamental Horticulture
Cornell University, Ithaca, New York 14853

At Cornell University we have worked for the last eight years on improving and testing methods for increasing the success of softwood cutting propagation. We have focused on improved stembanding methods and stock plant etiolation schedules which extendthe production season in northern climates by moving stock plantsindoors early in the year. We have applied stock plant etiolationand stem banding with success to nearly 60 ornamental tree species and cultivare (12). These methods consistently improve the rooting percentages, root numbers, and quality produced by species whichare reputedly very difficult to root, and extend the window ofpropagation opportunity, allowing higher rooting responses up to 2 to 3 months after the rooting of untreated material has falien-off. Admittedly, our interests have been research-based, and etiolation and banding have been useful tools for our investigations into thephysiological and anatomical bases for adventitious root formation stem cuttings.

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Banding is a localized form of etiolation using hormone-laden black Velero tape to cover the base of the shoot as it is developing on the stockplant.

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All of the species except the Japanese tree lilac showed strong responses to the use ofindole-3-butyric acid (IBA) as a 5-sec dip at sticking. The European hornbeam and Turkish hazelnut responded to the application of Hormodin 3 at the time of banding, while the 'Spring Snow 'crabapple responded to both etiolation and banding, with no additional response to hormone on the band. The Japanese tree lilac also responded to hormone on the band, and showed a synergism between banding and prior etiolation. Greenhouse forcing also improved overall rooting percentages over that seen in field-grown cuttings, a common observation in cutting propagation.

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Although Cannabis cuttings and layers root easily, variations in rootability exist and old stems may resist rooting. Selection of rooting material is highly important. Young, firm, vegetative shoots, 3 to 7 millimeters (1/8 to ¼ inch) in diameter, root most easily. Weak, unhealthy plants are avoided, along with large woody branches and reproductive tissues, since these are slower to root. Stems of high carbohydrate content root most easily. Firmness is a sign of high carbohydrate levels in stems but may be confused with older woody tissue. An accurate method of determining the carbohydrate content of cuttings is the iodine starch test. The freshly cut ends of a bundle of cuttings are immersed in a weak solution of iodine in potassium iodide. Cuttings containing the highest starch content stain the darkest; the samples are rinsed and sorted accordingly. High nitrogen content cuttings seem to root more poorly than cuttings with medium to low nitrogen content. Therefore, young, rapidly-growing stems of high nitrogen and low carbohydrate content root less well than slightly older cuttings. For rooting, sections are selected that have ceased elongating and are beginning radial growth. Staminate plants have higher average levels of carbohydrates than pistillate plants, while pistillate plants exhibit higher nitrogen levels. It is unknown whether sex influences rooting, but cuttings from vegetative tissue are taken just after sex determination while stems are still young. For rooting cloning stock or parental plants, the favorable balance (low nitrogen-to-high carbohydrate) is achieved in several ways:

1 - Reduction of the nitrogen supply will slow shoot growth and allow time for carbohydrates to accumulate. This can be accomplished by leaching (rinsing the soil with large amounts of fresh water), withholding nitrogenous fertilizer, and allowing stock plants to grow in full sun light. Crowding of roots reduces excessive vegetative growth and allows for carbohydrate accumulation.

2 - Portions of the plant that are most likely to root are selected. Lower branches that have ceased lateral growth and begun to accumulate starch are the best. The carbohydrate-to-nitrogen ratio rises as you move away from the tip of the limb, so cuttings are not made too short.

3 - Etiolation is the growth of stem tissue in total darkness to increase the possibility of root initiation. Starch levels drop, strengthening tissues and fibers begin to soften, cell wall thickness decreases, vascular tissue is diminished, auxin levels rise, and undifferentiated tissue begins to form. These conditions are very conducive to the initiation of root growth. If the light cycle can be controlled, whole plants can be subjected to etiolation, but usually single limbs are selected for cloning and wrapped for several inches just above the area where the cutting will be taken. This is done two weeks prior to rooting. The etiolated end may then be unwrapped and inserted into the rooting medium. Various methods of layers and cuttings rooted below soil level rely in part on the effects of etiolation.

4 - Girdling a stem by cutting the phloem with a knife or crushing it with a twisted wire may block the downward mobility of carbohydrates and auxin and rooting cofactors, raising the concentration of these valuable components of root initiation above the girdle.​

http://www.mellowgold.com/grow/mjbotany-removed/marijuanabotany2.html

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