Environmental Control of Plant Growth

447 Pages·1963·8.413 MB·English

by  L.T. Evans (Eds.)

Environmental Control
of Plant Growth
Proceeding osf a Symposium
Held at Canberra, Australia, August, 1962
Edited by
L. T. EVANS
C.S.I.R.O Division of Plant Industry
Canberra, Australia
1963
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Participants in the Symposium
Nnmbersin parenthesesdenotecontributorsto thepresentvolnme
andthepagesonwhichtheir contribut.ionsbegin.
D. E. ANGUS, C.S.I.R.O.Divisionof MeteorologicalPhysics,Melbourne,
Australia
R. D. ASANA, IndianAgricultural ResearchInstitute,NewDelhi, India
L. A. T. BALLARD, C.S.I.R.O.Division of Plant Industry, Canberra,
Australia
H. N. BARBER, U1~iversity of Tasmania,Hobart, Tasmania,Australia
H. D. BARRS, C.S.I.R.O.Division of Land Researchand Regional
Survey,Canberra,Australia
N. C. W. BEADLE, Universityof NewEngland,Armidale,Australia
J. BLACK, WaiteAgriculturalResearchInstitute,Adelaide,Australia
J. BONNER, CaliforniaInstituteofTechnology,Pasadena,California
H. A. BORTHWICK, U.S.Departmentof Agriculture,Beltsville,Maryland
(233)
W. BOTTOMLEY, C.S.I.R.O.])i1.n:sion of Plant Industry, Canberra,Aus-
tralia
E. BUNNING, BotanicalInstitute,Tubingen,Gerrnany
J. A. BUSINGER, UniversityofWashington,S~attle, Washington
P. CHOUARD, TheSorbonne,Paris,France
C. F. COOPER, AgricultureResearchService,Boise,Idaho
J. P. COOPER, WelshPlantBreedingStation,Aberystwyth,Wales(381)
A. B. COSTIN, C.S.I.R.O.DivisionofPlantIndustry,Canberra,Australia
R. L. CROCKER, UniversityofSydney,Sydney,Australia
R. M. DAVISON, Fruit ResearchDivision, D.S.I.R., Auckland, New
Zealand
O. T. DENMEAD, C.S.I.R.O. Division of Plant Industry, Canberra,
Australia
C. M. DONALD, Waite A.gricultural ResearchInstitute, Adelaide,Aus-
tralia
A. J. DYER, C.S.I.R.O.Division of MeteorologicalPhysics,Melbourne,
Australia
D. E. ELRICK, C.S.I.R.O.DivisionofPlantIndustry,Canberra,Australia
L. T. EVANS, C.S.I.R.O.Divisionof PlantIndustry,Canberra,Australia
(421)
J. FALK, C.S.I.R.O.DivisionofPlantIndustry,Canberra,Australia
H. C. FORSTER, Universityof Melbourne, MelbourneA, 'U8tralia
O. H. FRANKEL, C.S.I.R.O. Division of Plant Industry, Canberra.
Australia (439)
'I
vi Participants in the Symposium
P. GAASTRA, Laboratory of Plant Phys1:ologicalResearch,AgT1:c'll.ltural
f.ln1:versity,Wageningen,TheNetherlands(113)
C. T. GATES, C.S.I.R.O.Division of Trop1:cal Pastures,Brisbane,Au.s-
tralia
K. T. GLASZIOU, ColonialSugarRefiningCo.,Brisbane,Australia
M. B. GOTT, UniversityofMelbourne, MelbourneA, ustralia
A. E. GRANT LIPP, C.S.I.R.O.Division of Plant Industry, Canberra,
Australia
R. M. HAGAN, UniversityofCalifornia, Davis,'California
KARL HAMNER, Departmentof Botany, University of California, Los
Angeles,California (215)
S. B. HENDRICKS, U.S. Departmentof Agriculture,Beltsville,Maryland
(233)
W. M. HIESEY, CarnegieInstitutionof ll'ashington,Stanford,California
H. R. HIGHKIN, SanFernandoValley StateCollege,Northridge, Cali-
fornia
EIICHI INOUE, DivisionofMeteorology,.NationalInstituteofAgricultural
Sciences,Tokyo,Japan(23)
A. JOFFE, UniversityofPretoria,Pretoria,SouthAfrica
N. P. KEFFORD, C.S.I.R.O.Division of Plant Industry, Canberra,Aus-
tralia
H. J. KETELLAPPER, California Instituteof Technology,Pasadena,Cali-
fornia
D. KOLLER, HebrewUniversity,Jerusalem,Israel
Y. P. KONG, RubberResearchInstitute,KualaLumpur,Malaya
P. J. KRAMER, DukeUniversity,Durham~ NorthCarolina
ANTON LANG, California Institute of Technology,Pasadena,California
(405)
J. LANGRIDGE, C.S.I.R.O.DivisionofPlantIndustry,Canberra,Austral'ia
(367)
EDGAR LEMON, U.S. Departmentof Agriculture and Cornell University,
Ithaca,NewYork (55)
J. LEVITT, UniversityofMissouri,Columbia,Missouri (351)
E. T. LINACRE, C.S.I.R.O.Irrigation ResearchStation,Griffith, N.Ag.W.,
Australia
L. J. LUDWIG, C.S.I.R.O.DivisionofPlantIndustry,Canberra,Australia
I. C. McILROY, C.S.I.R.O.Division of Meteorological Physics,Mel-
bourne,Australia
J. R. MCWILLIAM, C.S.I.R.O.Division of Plant Industry, Canberra,
Australia
L. H. MAY, WaiteAgriculturalResearchInstitute,Adelaide,Australia
A. MILLERD, WaiteAgriculturalResearchInstitute,Adelaide,Australia
Pa~ticipants in the Symposium vii
F. L. MILTHORPE, Universityof Nottingham,Loughborough,England
K. J. MITCHELL, PlantPhysiologyDivision,D.S.I.R.,PalmerstonNorth,
NewZealand
H. MOHR, BotanicalInstitute,Freiburg,Germany
J. L. MONTEITH, RothamstedExperimentalStation,Harpenden,Herts.,
England (95)
R. M. MOORE, C.S.I.R.O.DivisionofPlantIndustry,Canberra,Australia
F. H. W. MORLEY, C.S.I.R.O.Division of Plant Industry, Canberra,
Australia
L. G. MORRIS, National Institute of Agricultural Engineering,Silsoe,
England
D. N. MUNNS, C.S.I.R.O.Division of Plant Industry, Canberra,Aus-
tralia
C. D. NELSON, Departmentof Biology, Queen'sUniversity, Kingston,
Ontario, Canada(149)
C. NITSCH, ThePhytotron,C.N.R.S.,Gif-sur-Yvette,France
J. P. NITSCH, ThePhytotron,C.N.R.S.,Gif-sur-Yvette,France(175)
E. O'NEILL, C.S.I.R.O.Divisionof PlantIndustry,Canberra,Australia
D. F. PATON, Australian}lational University,Canberra,Australia
R. L. PERRY, UniversityofCalifornia,LosAngles,California
J. R. PHILIP, C.S.I.R.O.DivisionofPlantIndustry,Canberra,Australia
M. E. D. POORE, UniversityofMalaya,KualaLumpur,Malaya
M. C. PROBINE, DominionPhysicalI.Jaboratory, D.S.I.R.,Lower Hutt,
NewZealand
D. PRUE, UniversityofReading,Reading,England
L. D. PRYOR, AustralianNationalUniversity,Canberra,Australia
S. D. RICHARDSON, ForestResearchInstitute,Rotorua,NewZealand
R. N. ROBERTSON, UniversityofAdelaide, AdelaideA,ustralia
M. B. RUSSELL, UniversityofIllinois, Urbana,Illinois
TOSHIRO SAEKI, BotanicalInstitute,Universityof Tokyo,Tokyo,Japan
(79)
W. W. SCHWABE, A.R.C. Unit of Plant Morphogenesisand Nutrition,
WyeCollege,Kent,England(311)
W. V. SINGLE, Departmentof Agriculture,Tamworth,N.S.W.,Australia
R. O. SLATYER, C.S.I.R.O.Division of I.Jand Researchand Regional
Survey,Canberra,Australia (33)
R. M. SMILLIE, BrookhavenNational Laboratory, Upton, New York
SOETOMOSOEROHALDOKO, BotanicalResearchInstitute,Bogor,Indonesia
W. R. STERN, C.S.I.R.O.Division of LandResearchandRegionalSur-
vey,Canberra,Australia
F. C. STEWARD, Departmentof Botany,Cornell University,Ithaca,New
York (195)
viii Participants in the Symposium
W. C. SWINBANK, C.S.I.R.O.Division of MeteorologicalPhysics,Mel-
bourne,Australia
C. Bo TANNER, Departmentof Soil Science,University of Wisconsin,
Madison,Wisconsin(141)
Ro J. TAYLOR, C.S.loR.O.DivisionofMeteorologicalPhysics,Melbourne,
Australia
Ko Vo THIMANN, HarvardUniversity,Cambridge,Massachusetts
Ro Go THOMAS, Plant PhysiologyDivision, DoS.I.R.,PalmerstonNorth,
NewZealand
Jo S. TURNER, Universityof Melbourne,Melbourne,Australia
AUSEKLIS VEGIS, InstituteofPhysiologicalBotany,UniversityofUppsala,
Sweden(265)
D. Ao DE VRIES, DepartmentofPhysics,TechnologicalUniversity,Eind-
hoven,TheNetherlands(5)
I. F. WARDLAW, C.S.loRoO.Division of Plant Industry,Canberra,Aus-
tralia
P. F. WAREING, UniversityCollegeofWales,Aberystwyth,Wales
Do Jo WATSON, RothamstedExperimentalStation, Harpenden,Hertso,
England(337)
Fo W. WENT, MissouriBotanicalGarden,StoLouis,Missouri(1)
R. F. WILLIAMS, CoSoloR.OoDivision of Plant Industry, Canberra,
Australia
Go L. WILSON, UniversityofQueenslandB, risbane,Australia
JAN A. D. ZEEVAART, CaliforniaInstituteof Technology,Pasadena,Cali-
fornia (289)
.To Ao ZWAR, C.SoloR.O.DivisionofPlantIndustry,Canberra,Australia
Foreword
This symposium was generated by Dr. Ο. H. Frankel as a celebra­
tion of the opening of Ceres, the Canberra phytotron, and a stimulus
to the work to be done in it. What success it enjoyed was largely due
to his demonic energy.
The aims of the symposium were, first, to consider the natural
microenvironments of plants and the relations between natural and
controlled environments and, second, to consider the physiological and
genetic basis of responses by plants to environmental conditions.
Not to spread ourselves too widely, discussion was centered on the
climatic component of environment. Two committees, and suggestions
from many individuals, shaped the program. The speakers were asked
for perspective appreciations of their allotted topics, ones which we
thought were central to our theme, if not exactly what our speakers
would have chosen. The accounts of the discussions which occupied
most of the symposium time were prepared by the discussion leaders,
with the assistance of the recorders, before they left Canberra rather
than after further visits to the library, the statistician, and the labo­
ratory. They were asked to give the drift of the discussions rather than
the whole of them, and I am indebted to them all for doing this so
promptly, and to Dr. N. P. Kefford for making them do it so promptly.
Thanks are also due to Mrs. J. Johnstone for careful typing, Mrs. K.
Bretz for maintaining records of manuscripts, and Miss A. E. Grant Lipp
for assistance with the proofreading.
The symposium was sponsored by the Australian Academy of Science
and by the International Union of Biological Sciences. Its realization
was made possible by grants from them and also from the Rural Credits
Development Fund of the Reserve Bank of Australia, the Commonwealth
Banking Corporation, the Colonial Sugar Refining Company, and
Imperial Chemical Industries, to all of whom the symposium organizers
render thanks.
L. T. EVANS
Canberra A, ustralia
April, 1963
ix
CHAPTER 1
The Concept of α Phytotron
F. W. WENT
Missouri Botanical Garden
St. Louis, Missouri
Man is involved in a tremendous struggle with his environment. In the
original, unaltered environment, less than one primitive man can live and
find sustenance on a square mile, and under such conditions life is hard,
as the Australian aborigine or the Indian in the Amazon jungle demon­
strate. By altering the environment modern man has achieved a more
than thousandfold increase in population density. But the frequent
famines or near-famines in the most densely populated areas of Asia
indicate how precarious man's control over his environment is.
Few of us realize that even in the technologically and scientifically
most advanced countries famine and disaster are not far away, even if
we disregard the effects of all-out atomic warfare. We are continuously at
war with hundreds of kinds of microorganisms, and an equal host of
insects. Relaxing of our vigilance for only a short while would return us
to the plague-ridden Middle Ages; malaria and tuberculosis would lay
their heavy hand of death on millions of people, blight and rusts and
other parasitic fungi would decimate our harvests. And even in spite of
our vigilance rabbits or prickly pear or other pests may strike any
country at any time.
With the rapidly increasing world population we need a much better
and deeper knowledge of our natural environment if we want to keep
abreast of insects and other pests. We must use all of the methods at our
disposal: mechanical, chemical, biological, and ecological. Chemical pest
control has recently come under severe criticism, but we have little choice
in the matter: either man or insect controls the earth. As one alternative
to poisons the ecological control of pests and diseases is suggested. For
such ecological control we have to know in great detail the life cycles of
the attacking and the attacked organism, which in most cases are fairly
well investigated, and the environmental factors, which are but poorly
understood. Also, problems of epidemiology are probably largely de­
pendent upon unknown effects of the environment. The yield of crop
plants is to a large extent dependent upon the environment in a mostly
ι
2 F. W. Went
unknown manner. Thus environment seems to be the key word in an
amazing number of unsolved or partially solved problems.
At this conference we are concerned with just one aspect of man's
environment, namely the plant world, and again mainly with the en­
vironmental aspects of plant development. The Canberra phytotron is a
powerful tool to come to a better understanding of plant growth and
development in general, and more specifically to an understanding of the
climatic aspects of plant performance. For in this phytotron it is possible
to control plant environment to a degree, and with a flexibility, hitherto
unachieved.
The least known aspect of plant environment is the way in which
atmospheric factors, the weather, influence plants. By proper breeding,
high-performing varieties can be produced; by chemical sprays, weeds,
pests, and diseases can be controlled; by fertilizing, a favorable nutrient
balance in the soil can be maintained; by irrigation an optimal water
supply is possible; by proper agricultural practices such as ploughing,
hoeing, defoliation, etc., man has a remarkable degree of control over his
crop plants. The major factor which is still uncontrolled is climate, and
in many crops it is just the climate which causes the greatest fluctuations
in yield from year to year. This is particularly well demonstrated in the
tomato yields in the various states of the U.S. over a series of years.
There are several ways in which the effects of the weather on plants
can be studied. The one most generally used, because it requires least
equipment, is the correlational one. A single value, usually yield per acre,
is measured in successive years for the same locality (e.g., the Broadbalk
plots at Rothamsted), and then regression coefficients are calculated for
the various climatic variables. There are many refinements of this general
method, e.g., intermediate stages in development are analyzed as well
(sugar accumulation in sugar cane), or the factors involved in total
yield production are differentiated (Gregory's growth analysis), but the
general principle remains a correlational analysis. This method will be
discussed in other chapters. I only want to point out some of its inherent
difficulties: the almost unlimited number of variables and combinations
of variables, and the inability to tell a prion if the weather effects are
direct or indirect or delayed (sometimes as much as 1 \ years, as in the
flowering of the peach).
Another method is to measure a particular parameter of the plant,
such as stem length, at frequent intervals and correlate this with the
immediately prevailing weather conditions. In this way the plant is used
more or less as a meteorological instrument, integrating the weather
factors important in its growth.
An entirely different approach to the weather problem is to modify it,
1. The Concept of α Phytotron 3
such as has been done for centuries by plant growers. They provide shade,
windbreaks, irrigation, different exposures, frost protection, etc. Thus the
effect of the specially modified factor in the context of the whole fluctuat­
ing system of all other weather factors can be assessed. This method
usually leads to only tentative conclusions, which are likely to vary more
or less from year to year, because of the enormous complexity of the
system, and the hundreds of uncontrolled factors which may modify the
response.
We finally come to experimentation under completely controlled and
reproducible weather conditions. This is the principle of the phytotron.
It still retains a great deal of complexity inasmuch as many variables
are involved, but most of them are controlled independently of each
other.
We must recognize that the principle of complementarity of Bohr holds
here. As one measures one parameter with greater and greater precision,
one has to sacrifice the analysis of the others which have to be kept under
less and less normal conditions. The most clear-cut case is the work of
Highkin. By growing peas under completely controlled and constant
temperatures, he changed his reaction system, the pea, to such an extent
that it was not the same organism anymore. The same can be said of the
tomato: one cannot properly measure development under completely
constant conditions, since the reaction system requires a circadian rhythm
to react normally. Here we are dealing with the uncertainty principle in
biology: even though the measuring of the system may not interfere
with the measurements, the experimental setup interferes with the system.
It was not until my last experiments in the Earhart Laboratory, studying
the temperature coefficient of the circadian system of the tomato, that I
became aware that all my work of the previous 20 years with the thermo-
periodicity of tomatoes would have to be repeated, and carried out under
optimal cycle length conditions. For practical purposes the experiments,
all carried out in a 24-hour cycle, were satisfactory, but to come to a
complete understanding of what effects temperature has on the tomato
plant, experiments should have been carried out also under different
lengths of the circadian rhythm.
The first work carried out in the Earhart Laboratory was in part ex­
ploratory. It was intended to find in which fields of botanical inquiry a
phytotron was most significant. Actually it turned out that every field,
from the theoretical to the practical aspects of botany, benefited.
We can expect that, limited only by the ingenuity of the research
workers, the Canberra phytotron will also serve almost all branches of
botany, both theoretical and applied.
With an environment which differs in a number of important ways