Seed Dormancy Discussions

5 August 1996-17 September 1996 - Germination Test Discussions


Date: Mon, 5 Aug 1996 17:35:41 -0400 (EDT)
From: "Jan Ferguson Spears" (JSPEARS@cropserv1.cropsci.ncsu.edu)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Germination of Nelumbo lutea (American lotus)

Does any one have information on the germination of Nelumbo lutea (American lotus)? We are in the process of looking at maturity and germination and are having some trouble finding information.

Jan Spears
Extension Seed Specialist
Box 7620 NCSU
Raleigh, NC 27695 USA
Phone (919) 515-4070
Fax (919) 515-7959
E-mail: JSPEARS@cropserv1.cropsci.ncsu.edu

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Date: Tue, 24 Sep 96 21:36:10 CDT
From: "Marc A. Cohn" (MCOHN@LSUVM.SNCC.LSU.EDU)
To: rlo1@cornell.edu (Ralph L Obendorf)
Subject: American lotus germination

Greetings all! Taking a break from the pH wars via an informal scavenger hunt for Dr. Spears re her post about germination of American lotus (Nelumbo lutea). The following is not a comprehensive search but may be useful as a pipeline to other literature via SCI and other electronic databases as well as the good old fashioned search and destroy mission of hand-searching Biological Abstracts or Seed Abstracts. Here's what's been found:

Meyer WC. 1930. Dormancy and growth studies of the American lotus, Nelumbo lutea. Plant Physiology 5:223-234.

Frankco DA. 1986. Studies of Nelumbi lutea (Wild) Pers. I. Techniques for axenic liquid seed culture. Aquatic Botany 26:113-117.

Kane ME et al. 1988. In vitro growth of American lotus embryos. Hortscience 23:611-613.

All of these provide either skeletal hints or reference to dormancy-breaking protocols that seem to work.
Another reference that I did not examine but looked interesting was:

Slocum PD. 1985. Propagating water lilies and aquatics. Brooklyn Botanic Garden Record 41:25-28.

In addition there were 2 Information sheets from Miss State Univ from October 1984 and March 1979 on American lotus by TL Wellborn. Since I could not put my hands on these at once, I don't know if they are cultural in nature or concern eradication.

Hope this helps. Now back to change into my Dr. Proton suit. Regards to all. M.A. Cohn, Dept Plant Path & Crop Physiol, Louisiana State Univ, Baton Rouge, LA 70803 USA.
Phone: 504-388-1464
Fax: 504-388-1415
Email: mcohn@lsuvm.sncc.lsu.edu

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Date: Thu, 15 Aug 1996 14:11:10 -0400 (EDT)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Grass Seed Germination

If anyone knows references about pH effect on seed germination of grass seeds please let us know.

Thank you very much.

Roberto Ferreira da Silva
e-mail: roberto@uenf.br
CCTA-UENF
Campos dos Goytacazes-RJ
Brasil

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Date: Tue, 17 Sep 1996 11:49:44 bst
From: "A J Murdoch, Reading University" (A.J.Murdoch@reading.ac.uk)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Grass Seed Germination (pH effect)

Dear Roberto
We have looked at effects of pH on the effects of dormancy-relieving chemicals on Avena fatua. An abstract of a paper presented at a Seed Ecology meeting in the UK is given below. The student who did the work is Ricardo Carmona. He is now at the University of Brasilia if you want to follow it up locally.
Best wishes
Alistair Murdoch.

Dual Effect of Sodium Azide on Weed Seed Germination
by A.J. Murdoch, R. Carmona and E.H. Roberts
The effects of pH on the action of sodium azide and of some other potential dormancy-relieving chemical treatments were investigated in soil and in buffer solutions on seeds of Chenopodium album, Avena fatua and Rumex crispus. Sodium azide had a dual effect such that it damaged and often killed seeds of C. album L. and Avena fatua L. seeds in acid soil (pH 4), while in basic soil it relieved dormancy of A. fatua. The response to potassium nitrate with ethephon was not affected by pH from 3 to 9 in any species, but at pH 6.2, mixing these two chemicals with azide was detrimental to C. album and A. fatua, perhaps because of an antagonism of nitrate and azide in the presence of ethephon. A mixture of five compounds (nitrate, ethephon, azide, thiourea and hydrogen peroxide) reduced the influence of pH on the deleterious effect of azide. The damage to C.album seeds by azide occurred equally at constant (20 C) and alternating temperatures (10 /20 C and 5 /25 C; 16h/8h), whereas relief of dormancy was much greater in the latter. The influence of soil characteristics on the efficacy of dormancy-relieving or weed seed killing treatments in the field [was] discussed.
________________
The following references may be useful:
1. Cohn, M.A. (1989). Factors influencing the efficacy of dormancy-breaking chemicals. pp. 261-267. in Taylorson, R.R. (Ed.) Recent Advances in the Development and Germination of Seeds. New York, Plenum Press.
2. Cohn, M.A., Butera, D.L. and Hughes, J.A. (1983). Seed dormancy in red rice, response to nitrite and ammonium ions. Plant Physiology 73, 381-384.
3. Cohn, M.A., Chiles, L.A., Hughes, J.A. and Boullion, K.J. (1987). Seed dormancy in red rice. VI. Monocarboxylic acids: a new class of pH-dependent germination stimulants. Plant Physiology 84, 716-719.
4. Cohn, M.A. and Hughes, J.A. (1986). Seed dormancy in red rice, response to azide, hydroxylamine and cyanide. Plant Physiology 80, 531-533.
Cohn and Hughes (1986) showed that the relief of dormancy of red rice seeds in the laboratory by azide occurred at pH values favouring the uncharged form (HN3), i.e. at acid pH.
5. Tilsner, H.R. and Upadhyaya, M.K. (1989). The effect of pH on the action of respiratory inhibitors in Avena fatua seeds. Annals of Botany 64, 707-711.

Dr A.J. Murdoch, Department of Agriculture, The University
Earley Gate, PO Box 236, READING RG6 6AT, U.K.
TEL.: +44 (0)118 931 6746. FAX: +44 (0)118 931 8297

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Date: Tue, 17 Sep 1996 13:02:37 -0600
From: adknapp@iastate.edu (A. D. Knapp)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Grass Seed Germination

Dear Roberto:
I would add the following to the recent list of citations that you received.

Palevitch, D. and Thomas, T. H. 1976. Enhancement by low pH of gibberellin effects on dormant celery seeds and embryoless half-seeds of barley. Physiol. Plant. 37:247-252.

Allen Knapp
Agronomy Department
Iowa State University
Ames, IA 50011 USA
Phone : (515) 294-9830
Fax: (515)294-3163
adknapp@iastate.edu

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Date: Tue, 17 Sep 96 22:52:50 CDT
From: "Marc A. Cohn" (MCOHN@LSUVM.SNCC.LSU.EDU)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Re: Grass Seed Germination

Re Allen Knapp's inclusion of the Palevitch and Thomas paper to the pH list: This is an important paper in the historical development of the Cohn pH studies. Tudor's paper was a key supporting component that provided a stimulant for the red rice studies. And yes, I sent him a personal thank you letter re the work. I remember his response well. He was pleased that his finding were of more general use. Just a note for the historians out there. Regards to all, M.A. Cohn, LSU Baton Rouge

Also for the curious: in red rice, I've shown a pH-dependent effect for GA confirming P and T. However, this effect only occurs in light conditions. In red rice in the dark, there's no effect of GA at any pH. This was reported in an Agronomy Abstract quite a while ago, but we've never had time to get back to it further. Which raises my question: I know of ca. 6 species where GA activity requires light. Is anyone doing anything with such a system at the molecular level. Seems like a nice system for real signal transduction studies. If anyone wants to play with this, we may be able to supply the red rice (if you don't live in a restricted area) or we could collaborate.

We're at mcohn@lsuvm.sncc.lsu.edu or FAX:504-388-1415 or the phone 504-388-1464 or the snail at Dept Plant Pathol & Crop Physiol, 302 Life Sciences Bldg, Louisiana State University, Baton Rouge, LA, USA if anyone wants to talk to us about it.

Marc A. Cohn
Department of Plant Pathology and Crop Physiology
Louisiana State Univ., Baton Rouge, LA USA

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Date: Wed, 18 Sep 1996 14:48:36 -0500 (CDT)
From: jdekker@iastate.edu (Jack Dekker)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Dormancy relief

I have general and specific questions about the recent dialogue on SeedBiologyList. The specific one concerns the relationship of darkening seed/polyphenoloxidase and the effect of pH discussed in replies to that question. Pardon my ignorance, I missed the connection and it sounds very interesting.

The general one concerns the responses about pH. Is there a hypothesis about endogenous pH and mechanisms that alter seed germinability? What is the relationship of exogenous pH solutions, sodium azide, exogenous GA, etc. to dormancy regulation/mechanisms in seeds. Thanks for any insight anyone can shed on these questions.
Jack

Jack Dekker, 3214 Agronomy Hall
Iowa State University, Ames, Iowa 50011 USA
TEL: (515)294-8229; FAX: (515)294-3163
E-Mail: (jdekker@iastate.edu)

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Date: Wed, 18 Sep 96 23:05:02 CDT
From: "Marc A. Cohn" (MCOHN@LSUVM.SNCC.LSU.EDU
To: SEED-BIOLOGY-L@cornell.edu
Subject: Dormancy relief

Jack, my boy! Dr. Proton is here, at your service! Most of the compounds you mentioned are weak acids, so adjusting the pH towards each ones pK puts them in the neutral form. Under these mild acid conditions, the chemicals break dormancy. However, at pH 7, nothing happens and the seeds are still alive after the unsuccessful treatments. We have shown that the successful treatments put the seeds under an acid load as has been demonstrated for many other systems, including spores and organisms other than plants.

That's where the facts end and the stories begin. The acid load could do any of about 1/2 dozen things which I discuss in the Sept issue of Seed Science Research. One possibility is that the protons are part of a signal transduction chain involving increased calcium levels and a re- sulting protein kinase/phosphatase modulated chain leading to gene activation. This would have to occur rapidly I suspect. We know that symptoms of glycolytic activation can be detected withing 2-4 hours after application of dormancy-breaking treatments.

Re the PPO question posted here previously: I must have missed this question or our system was on the blink and I didn't receive it. Can someone repost the question or email to me directly.

Regards to all, M.A. Cohn

Marc A. Cohn
Department of Plant Pathology and Crop Physiology
Louisiana State Univ., Baton Rouge, LA USA

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Date: Fri, 20 Sep 1996 09:37:34 -0500 (CDT)
From: jdekker@iastate.edu (Jack Dekker)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Dr. Proton on the spot

Hey Seed Biology List,
Thank you Dr. Proton (Marc) (who is Dr. Proton anyway?) for the timely response. This area sounds very interesting. I have another enquiry following your tale. You wrote:

Jack, my boy! Dr. Proton is here, at your service! Most of the compounds you mentioned are weak acids, so adjusting the pH towards each ones pK puts them in the neutral form. Under these mild acid conditions, the chemicals break dormancy. However, at pH 7, nothing happens. Successful treatments put the seeds under an acid load. That's where the facts end and the stories begin. The acid load could do any of about 1/2 dozen things which I discuss in the Sept issue of Seed Science Research. One possibility is that the protons are part of a signal transduction chain involving increased calcium levels and a resulting protein kinase/phosphatase modulated chain leading to gene activation. This would have to occur rapidly I suspect. We know that symptoms of glycolytic activation can be detected withing 2-4 hours after application of dormancy-breaking treatments.

Everyone:
This raises several questions in my mind some of you may want to comment on:
1. Has any type of evidence for this signal transduction chain been provided? Put another way, is there any physiological observations of this pH change occurring endogenously in seeds?
2. Is the time frame (Marc sez it must be a rapid process) adequate to explain the relief of seed dormancy as it is observed. Here I am thinking of my grass weed species, as well as grassy crop species, in which dormancy relief often is a gradual and incremental process (as well as rapid in other cases).
3. Do any of these chemicals mimic endogenous, plant synthesized, compounds in terms of structure, and (possibly more importantly) concentration at a tissue site?

Finally, I apologize for my confusion with Roberto's two questions I got mixed up (seed dormancy relief and seed coloration/PPO):

Re the PPO question posted here previously: I must have missed this question or our system was on the blink and I didn't receive it. Can someone repost the question or email to me directly.

Jack

Jack Dekker, 3214 Agronomy Hall
Iowa State University, Ames, Iowa 50011
TEL: (515)294-8229; FAX: (515)294-3163
E-Mail: (jdekker@iastate.edu)

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Date: Wed, 25 Sep 96 19:47:25 CDT
From: "Marc A. Cohn" (MCOHN@LSUVM.SNCC.LSU.EDU)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Dr Proton responds on the spot

Jack Dekker wrote:

Thank you Dr. Proton (Marc) (who is Dr. Proton anyway?) for the timely response. This area sounds very interesting. I have another enquiry following your tale.
This raises several questions in my mind some of you may want to comment on: 1. Has any type of evidence for this signal transduction chain been provided?

Dr Proton pumps up to respond: Not in seed dormancy. BUT there is substantial evidence for this series of phenomena in the activation of oocytes. See Cohn's article in the Sept 1996 issue of Seed Sci Research as well as Epel D (1990). The initiation of development at fertilization. Cell Differentiation and Development 29:1-12. Early literature that may be of interest (pre-signal transduction) can be accessed in Loeb, J. (1913) Artificial parthenogenesis and fertilization. Chicago, University of Chicago Press. See also: Lillie RS. 1926. The activation of starfish eggs by acids. J Gen Physiol 8:339-367.

Put another way, is there any physiological observations of this pH change occurring endogenously in seeds?

YES. See: Pack DA. 1921. After-ripening and germination of Juniperus seeds. Bot Gaz 71:32-60. stratification at 5C results in acidification of embryo extracts.

Eckerson S. 1913. A physiological and chemical study of after-ripening. Bot Gaz 55:286-299

Jones HA. 1920. Physiological study of maple seeds. Bot Gaz 69:127-152.

Rose RC. 1919. After-ripening and germination of seeds of Tilia, Sambucus, and Rubus. Bot Gaz 67:281-308.

Footitt S, MA Cohn. 1992. Seed dormancy in red rice. VIII. Embryo acidification during dormancy-breaking and subsequent germination. Plant Physiol 100:1196-1202. See figure 1 for non-dormant seeds.

2. Is the time frame (Marc sez it must be a rapid process) adequate to explain the relief of seed dormancy as it is observed. Here I am thinking of my grass weed species, as well as grassy crop species, in which dormancy relief often is a gradual and incremental process (as well as rapid in other cases).

The activation process can occur in seconds in the sea urchin system. There are so many steps in the process that there is no reason (at this point) to rule out a more extended series of events over time in more complex systems such as seeds. Signaling events could be transiently blocked at any step in the process as a "fail-safe" measure until the necessary dose of cold-temperature or other dormancy-breaking stimulus has been received.

3. Do any of these chemicals mimic endogenous, plant synthesized, compounds in terms of structure, and (possibly more importantly) concentration at a tissue site?

With seeds: you or I or someone will have to do the "get down in the dirt" experiments. But there's some hope. See Gehring CA, HR Irving, RW Parish. 1994. Gibberellic acid induces cytoplasmic acidification in maize coleoptiles. Planta 194:532-540. for a recent example Any interests in long-term collaboration on signal transduction will be welcomed. Bring your calcium probes and kinase kits. In addition, I'll be looking for a new Ph.D. student to begin this summer. Hurry now to apply if you want a shot at available fellowships and assistantships.
Regards from swampland, Dr. Proton and associates.

M.A. Cohn, Dept Plant Pathol & Crop Physiol, Louisiana State University, Baton Rouge, LA 70803 US of A
(mcohn@lsuvm.sncc.lsu.edu)
FAX: 504-388-1415
PHONE: 504-388-1464

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Date: Mon, 23 Sep 1996 16:25:25 +0200
From: Andrew Cairns (cairns@agron.unp.ac.za)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Dr. Proton on the spot -Reply

I am very interested in all this speculation on pH and dormancy. Can "Dr Proton" explain to me in terms of his pH theory how fumigation of grass seeds with ammonia breaks dormancy?

Andy Cairns
University of Natal, Pietermaritzburg
South Africa

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Date: Wed, 25 Sep 96 17:36:33 CDT
From: "Marc A. Cohn" (MCOHN@LSUVM.SNCC.LSU.EDU)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Re Cairns ammonia question - Dr Proton responds

Greetings all. Cairns asked about how to explain the dormancy-breaking activity of ammonia gas which he has reported on in several papers over the past years. First off, my group confirms this activity in red rice although the resulting seedlings are weakened and of poor vigor. A direct explanation for this effect does not exist in the seed literature. There is a large body of work addressing ammonia/ammonium ion activation in the sea urchin oocyte literature. As a consequence of an NH3 pulse, there is the induction of a calcium wave, increased inositol-tri-P and increased protein synthesis in a matter of minutes. A "pipeline" reference into this literature is: Epel D (1990). The initiation of development at fertilization. Cell Differentiation and Development 29:1-12. Weak acids also activate the oocyte system. See Lillie RS (1926). The activation of starfish eggs by acids. J Gen Physiol 8:339-367. Other references of interest can be found in our recent paper: Footitt SF, MA Cohn. (1992). Seed dormancy in red rice. VIII. Embryo acidification during dormancy-breaking and subsequent germination. Plant Physiol 100:1196-1202

Hope this helps.

M.A. Cohn, Dept Plant Pathol & Crop Physiol, Louisiana State University, Baton Rouge LA 70803 USA.
(mcohn@lsuvm.sncc.lsu.edu)
Fax: 504-388-1415
Phone: 504-388-1464

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Date: Fri, 11 Oct 96 11:32:59 +0400
To: SEED-BIOLOGY-L@cornell.edu
From: Natasha Obroucheva and Olga Antipova at
"Vladimir D. Tsydendambaev" (vladimir@ad.plantphys.msk.ru)
Subject: embryo acidification

Best regards from Russia!
Unfortunately we missed the first part of discussion on embryo acidification, and especially the explanation of Dr. Proton concerning dormancy release. Can he repeat it for us by e-mail? (already sent by R.L. Obendorf) We have found with germinating broad bean seeds that the acidification of ambient solution by imbibing axial organs starts at 68-70% water content (fr wt), i.e. 2-3 h prior to radicle emergence. This acidification of cell walls by proton extrusion through plasmalemma favors cell wall loosening and the beginning of cell elongation. These results were published in 1989 in "Structural and functional aspects of transport in roots", B.C.Loughman et al (Eds), Kluwer Academic Publishers, Dordrecht, p.41-44 and in 1994 in Russian Journal of Plant Physiology, V.41, N3, p.391-395 (in English).
Thank you, Dr. M.A.Cohn, for some old references on acidification in dormant seeds.

Our E-mails are: vladimir@ad.plantphys.msk.ru or pavel@rusplant.msk.su

Obroucheva Natasha and Antipova Olga
INSTITUTE OF PLANT PHYSIOLOGY
Moscow, Russia

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Date: Mon, 23 Sep 1996 17:50:49 +1200
From: Marc Greven grevem@whio.lincoln.ac.nz
To: SEED-BIOLOGY-L@cornell.edu
Subject: hormones in seed

I just joined the seed-biology group and are following the discussion on dormancy, GA and pH with much interest.

I am very interested in the possibilities of extending the influence of hormones from dormancy to "permanent dormancy" or loss of vigour and possibly viability.
Has any research been done in that direction? Can stress on the mother plant change the hormonal balance within the plant and subsequently the seed, to such an extend that the seed becomes less vigourous? Can the seed break down or counterbalance (with GA?) the vigour restricting hormones (ABA?) during germination?

Marc Greven, 320 Hilgendorf, Lincoln University, Canterbury, New Zealand.
E-mail address: Grevem@whio.Lincoln.ac.nz.

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Date: Mon, 23 Sep 1996 19:41:00 -0700 (PDT)
From: "Pallais, Noel" (N.PALLAIS@CGNET.COM)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Definition of thermodormancy: A question

In the preceding discussion about thermogradients for germination, the comment below (>>>>>) was made, which reflects a definition of thermodormancy that I have found often in the literature but that I don't agree with. And, I would like to request opinions so I can either change my way of thinking or persist with my understanding of the term "thermodormancy".

I am probably mistaken but in my mind seeds are "thermodormant" when they have acquired dormancy due to exposure to nonlethal but extreme temperature conditions. While seeds should be termed "thermo-inhibited" when exposed to temperatures which exceed their range of possible germination.

The distinction is a bit more than a linguistic matter to us since we work with true potato seeds, which are dormant (germination is impeded or slow, widespread and erratic) at harvest because the range of allowable germination temperatures is relatively narrow 15 C ( 2), while as storage procedes and dormancy is gradually lost, the upper allowable temperature for germination increases up to 29 C ( 2); the lower temperature limit may or may not slightly decrease a few of degrees depending on the genotype.

I like to describe true potato seeds as "dormant" when they don't germinate or have difficulty germinating under a temperature condition that otherwise would be favorable, and "nondormant" when they germinate rapidly and uniformily at 27 C. We have published evidence indicating thermodormancy ( i.e. nondormant seeds became dormant when stored at high temperature and moisture) may be induced in true potato seeds, and that true potato seed germination is thermo-inhibited at temperatures above 30 C.

HELP!

>>>>>Agreed. I would think that in cases of a dormancy such as thermodormancy in, for example, lettuce seed and possibly things like Amaranthus spp. which seem to have what I would consider a thermodormancy, this type of predictive or comparative modeling would be of value.

Noel Pallais
International Potato Center
n.pallais@cgnet.com

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Date: Wed, 25 Sep 1996 08:40:51 bst
From: Prof Richard Ellis (R.H.Ellis@reading.ac.uk)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Thermodormancy and conditional dormancy

Thermodormancy

Although the above is widely used in lettuce for example where germination of viable seeds no longer occurs at cool temperatures following exposure to warm temperatures, another term used where germination after harvest (etc) is limited to a very narrow range of temperatures to cover inability to germinate at cooler or warmer temperatures (i.e. different to thermodormancy) is conditional dormancy.

Richard

Professor Richard Ellis,
Department of Agriculture, The University of Reading,
Earley Gate, P.O. Box 236, Reading RG6 6AT, UK
Phone +44 (0)118 931 8488 Fax +44 (0)118 931 8297
e-mail: R.H.Ellis@reading.ac.uk

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Date: Mon, 7 Oct 1996 08:43:20 -0400
To: SEED-BIOLOGY-L@cornell.edu
Sender: aak1@nysaes.cornell.edu (Anwar Khan)
Subject: Thermodormancy and thermoinhibition

Noel:

I will attempt to answer the questions raised by you on thermoinhibition and thermodormancy and the general question of seed dormancy

Based largely on the work with light, chilling and GA requiring seeds, nondormant seeds imbibed under nongerminating conditions (notably in darkness) i.e. at supraoptimal temperature (thermoinhibition) or in an osmotic medium (osmotic inhibition) for relatively prolonged periods become thermodormant or osmodormant or simply dormant. Thermoinhibition thus can be regarded as an inhibitory treatment which if prolonged can lead to thermodormancy or simply dormancy induction. A bref soak at high temperature, in osmotic solution, or in ABA solution does not induce dormancy.

Noel, your observation with TPS is consistent with the suggestion that changes in embryo growth potential, measured as a decrease in embryo growth rate or a reduced capacity to germinate in a low water potential medium, play an important role in dormancy. You have given examples from potato and partially stratified peach seeds. The same is true for other seeds including, lettuce, apple, pear, ginseng. Embryos excised from seeds even with deep dormancy (i.e., ginseng and apple) are able to grow but the growth rate is extremely slow. So you are right in saying that dormancy does not mean a complete arrest of growth. Growth potential of embryos derived from dormant seeds is not high enough to breach the covering structures. There are intermediate situations, no doubt, which would result in a lower or higher germination percentage in a seed population or lower or higher growth rate when compared to fully dormant or fully nondormant embryo.

Some of my thinking on dormancy is summarized in a recent review:

Khan, A. A. 1996. Control and manipulation of seed dormancy. In: G. Lang, ed. Plant Dormancy: Physiology, Biochemistry and Molecular Biology. CAB International (in press).

Anwar Khan
NYSAES, Cornell University
Geneva, NY 14456
USA
TEL: 315-787-2247
FAX: 315-787-2320
E-MAIL: aak1@nysaes.cornell.edu

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Date: Tue, 17 Sep 1996 09:46:37 -0300 (GRNLNDDT)
From: roberto@uenf.br (Roberto Ferreira da Silva)
To: SEED-BIOLOGY-L@cornell.edu
Subject: Dry bean seed coat darkness

We are interested in research work related darkness on seed coat of dry bean seeds during storage. So far we would like to get some informations concerned to mechanisms which might be involved in this type of physiological disorder? Enzyme Polyphenoloxidase seems to be involved in this process. Procedures in order to detect the enzyme activity as well as other mechanisms involved in this phenomenon if available would be welcome.
Thank you so much.

Roberto Ferreira da Silva
CCTA-UENF
Campos dos Goytacazes-RJ
Brasil

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