I S D E S T ' I R O N M E S T . I1 ER D. BASCROFT -lvenite, Ithacn, S e t o Yor6
eccii'cd J u l y 13, 1948
41ccording t o J . H. Hilles ( l o ) , Director of the 17erniont;lgricultural Esperiinent Station. the making of maple sugar \\-as a pioneer industry, established among the Indians (trihe not given) prior to 1673. The early 17ermont settlers learned the art from the Indians ant1 dependrd almost entirely on maple sugar for their domestic supply of sugar. Indeed, this practice \\a ill much in vogue tivo generations ago. The hulk of maple mgar is made in six states--T7ermont, Sei\- Tor].;, Ohio, Michigan. Pennsylvania, and Se\v H:impshire, named in the order of the output. These furnish 93 per cent of the sugar and over 80 per cent of the syrup. There is no maple sugar made south of 35" latitude or west of 95" longitude. S o r t h Carolina and Tennessee mark the soiithern and western limits of the growth of the sugar maple. The sugar maple does not grow in Europe save in arboretums:. Late in March the \\-eather begins t o warm up a bit' in \-wmont. The nights are st,ill frosty; but the sunny days are genial, and there is a suggestion in the air of the coming of spring. If, at this time, the trunk of the sugar maple is tapped hy boring int,oit for a depth of 3 in. or less and a "sap spout" or spigot is inserted, the sap exudes and falls, drop by drop, quickly or slowly according to the weather and the time of day. K a r m days and freezing nights form ideal sugar weather. The alternation of external temperatures above and belon- 0°C. (32°F.) is follo\ved during the sugar season hy an alternation of pressure and of suct>ion. This produces a sort of pump action in the region of the tap hole. During the day pressure forces into the orifice all of the sap located in the adjacent ti::-$ties. The suction which ensues on freezing nights d r a m more sap into these tissues, which in turn is forced out when the tree narms up again. The entrance of thc air is hindered, if not quite prevented, hy the impermeability of the wet memhranes. Thus new supplies of sap are constantly drawn t o and forced out of the tap hole \\-hen meteorological conditions set the pump at work. While the flow of sap depends upon the \\-eather caonditions the year that the t,rce is tapped, the concentration of the sap depends, among other things, on the weather of the year hefore. The caiGohydrate foods (st'arcah, sugar, etc.) are all manufactured in the green leaves under the influence of the sunlight. I t is important t o emphasize this fundamental point, because the sugar content of the sap depends upon the conditions of the preceding season as t o sunlight and leaf development. There has been abundant evidence of this ivhen the defoliation of the trees by forest caterpillars was followed by seasons in which the sap carried much less sugar than usual. This must mean that the sugar is stored in the trunk and branches during the winter and makes me Tvonder \\-hethey i t might not' be possible t o devise some method of making maple sugar in the
468
\\-ILDEH D . I 1 . 1 S C R O F T
autumn instead ot in the spring. The chemist of today ought t o be able to improve on t’he unspecified Indians of three centuries ago. The S e w I‘ork Tinics of l i a y 20, 1948 stated that the flon- of maple sap \vas small that spring and the concentration of sugar as low. “It is nature that must’take the blame for the poor crop. Last fall was too dry and the spring did not have enough of the freezing nights antl than-in?; days that assure a good run of sap.” ET-ideiitly the nian who irrote this line\\-t h a t the weather in the year hefore the tree is tapped has an effect on the concentration of sugar in the sap. Many people do not lmon- this. In 0ii.r Flowering 1T70dd(15) the author, Rutherford Platt, says that the SenJersey tea shrub, Ccanotli l i s amcricari u s , has \\-hite flon-ers in the Pocono mount a i n s . . . “Ceanofhus is abundant in California hills where its flowers are skyhlue. They call it California lilac-.lt misnomer.” I took this to mean that Ccnriothiis americari I L S has sky-blue flon-ers in California and white ones in the Pocono mountains. n-hich sounds like a striking though unexplained effect clue t o en\-ironment ; but Professor J. IT.licI3ain at Stanford University and Profes>or Knudson, the head of the Department of Botany at Cornel1 University, both say that) Ceaizothus airicrican.us does not oc(:ur in California and that coiisequently the white flo~vcrsin the Pocorio mountains are not the same as the tilue floirers of the California lilac. .hfter some delay I got in touch \\-ith 1\11..l’latt. \rho confirmed the statements of Professor llcl3ain and Professor I~,in his garden in X l t o n . 11 whusetts. It \vas not a cwxnmercial herry, 1)ecause i t \vas too delicate t u stai ransportation, h u t \vc thought that it n x s a \)e,ttcr I w ~ for y eating t h a n :my of the red strawberries that \ve ex-er had. I have mentioned this before. hut 1 have just learned that it is interesting t o me no\\for a different reason. I’rof’essor Slate, of the S m v I’orl; Experiment Station a t (ieneva, &-e\\- York. \viwte me that they gre\v the T,ennig’s ITIiite prioi, t o 1890. H e does not commit himself :is t o the taste of the l)ci.ries, but says that the licrry \vas a yery pale red in c ~ ) l o i on , the side to\vards the sun and a creamy \vhite on ill the same class as the red apples the other side. That puts this ivhite h i antl the red pears. It is interesting that apparently nohody thought that this ivas worth comnieriting on in print. Dr. Rogers of the IGmt Itworporated Society for Promoting Experiments in Horticulture a t Xaidstone, Kent, wrote to Professor Findlay that “black cur-
HEREDITS . i S D ESYIROSJIEST.
I1
46 1
rants a-ill certain1)- hlacken in the shade, hut I think that straivherries wed ultraviolet though I have not tried this.." I thought and said (3) that Dr. Rogers had made a h d giie s to strawberries needing ultrnviolet light. Sow I :mi riot so sure 2ihotit i t . It is possible that if stradwrries are g o \ v n in :i green11oiis.r the color \vi11 v:iry somen-hat ivith the exposure to u1tr:iviolet light, In 1942 311.. Platt puldishetl nn earlier hook, This G r w / f TT70r.ltl ( 1 7 , ivhich rereivd thc .John Hiirroughs .\\vnid of 1945. It rontains :I niirnher of interesting pasXlgC".
'..Is soon as 3 1e:ii has its supply of f m l i sap c u t off by t h e pluggiiig of its pipelirtes, i)hotosyiithesis stops. C'hlorophyll is an instable chemical tti:it must be constantly renerved c o exist. [Platt ~ h o u l dhave said t h t c~hlorophyllis :in easily osidized sulistaiicr r:ithei, than :in inst:rtile substaiice.1 Therefore tlie green c h l o i ~ o p h ~ - lisolated l, iii the 1e:if by t h e cutting off of sap. is destroyed by t h e sun's r:iys :tiid dis:ippe:irs. In t h i s w:ty grecii color, which is the dorriitiutit pigment in thr leaf, is t.cnioved. *,Whatabout t h e nutunlit crimson of the red m:tple : i d t h c \*irgiiii:i creeper. the sc:irlet of o ~ i k e .the dark red of snssnfrus leaves, t h e pluin coloririg of t l i e asht.s? Thesc red ant1 bluish tones are caused by u sug:~rcheiiiic:tl i i i the cell s:~pc:illecl :inthoc>xnin. Autlio. cyniiin is not a pigment whew spccks front :irounti i n t h ? snp :IS chiorc)ptiy!~:itid c:irotiti do. it is :L sup:ir in solution."
H a r t does not mention that anthocyanins are formed in tivo \vuys.~-througli rrdiivtion of fl:ivon~shy light in the presence of R suitable enzyme, and through h).drolysis of a leucoanthoc*jraninwithout the wtion of light. "The l~i~illiaricc~ of tlir fall foliage m:c. Ire erili:incetl tiy the weather conditions. The iiitetisity o f light h:is much t o do w i t h tlie intensity of t h e red :iiid purple of t h e sugar cheniic:il, For this re:isoii. t h e hriglitest, r o l o v s ;ire formetl \vlieri t h e f:d1 se:isun is briglit : i r i d cle:ii,. It there is :iii cxscess of cloudy \ve:ither t h e >-t,llo~v:ind oriiiige of c:irot i n :we not :iff e c t r d . They glow on moist :tiid misty d n y s w i t h exquisite rich pastel hues. On t h e other hand. t h e reds and piiiyles of t h e anthocy:iniiis :ire clulled by cloudy weathei,. ";\utunin colors do not depend on t h e frost. 1'rob:ibly they did in some prehistoric : ~ g e when t h e ingr:iined habits of tlie b i ~ o : ~ - l e a v ct dw e a n ~ , i ' ehriiig foi~meti; but i i i o u r d : ~ this y behavior is :iutom:itic."
-1 yrcat deal of interesting work on the flo\\.ering ant1 frriiting of plants :is conlidled hy the length of day has hcen done hy \I-.I\-.(iarner, plant physiologist in t h e Ilepartmcwt of Algriciilttire in \T':ishiiigton. :tiid his cd1al)or~itor.. (1. 2 . T. S). ( h i e of the most c*h:ir:ictr~ristiofeatures of plant gro\vth outside the tropic:: is :hf>mniketl tendency sho\vn by n r i o i i s spwiez t o f l o \ \ ~and r fruit only a t certain wriodi of the year. This twhavior i o constnnt that cwtain plants come to hc * l o . ~ lidentified y i v i t h e:ic*h of tlie seasons, in t h e same i\'ay as the coming and Coirig of migratory hirtls in spring :ind fall. I n midivinter the hlossoms of ayc*lamenand freesia, the brilliant color of poinscttizi, :ind the fruits or berries )f :trdisiii. all are reminclers of the scason: in spring we expect t o see the unfolded )lossoms of forsythia. wilt1 violet, crocus, redbud, dog~vood,and other typical Ilants. -1s summer approaches, the poppy, rhododendron, iris, and columbine legin flowering; in the autumn salvia, aster, cosmos, dahlin. and chrysanthemum ~eraldthe approacnhing end of the open gron-ing season ( 7 , p. 3ii).
IYhile marlmi 1-cgiilarity iu t h e time of flowering ancl r'rniting is the rule in plants so long a s they arc groivn in any particular locality in temperate regions:, transferring plants from one region t o another may change their habits greatly. -~lspecies ivhich f l o \ v c i ~and fruits readily may beroine sterile in another, oi'! in some instances. the tiiiic ot' fioxering may be (ahanget1from spring t o fall, or ~ , i a versa. -\gain, plants behaving as anniials in one region may liecome biennials in another. These changes in t h e behavior of plants when gro\vn outside their n a t i ~ eregions furnish strong evidence that external factors control t,he processes of flowering and fruiting arid nlso suggest the possihilit>- of artificial control. Garner and AUartl:ire talking nlmiit heredit,?. and environment in fact, though they do not use my \voids, \vhich had not heen thoiiglit of tjy me at that time Garner and A1l;ird say ( 7 , p. 3 i O ) that the ordinary varieties of cosmos regularly flower in the fall in nort1iei.n latitudes if they arc planted in the spring or summer. If gro~i-iiin :i warm greenhouse during the winter months the plant.: also flower readily, so that the cooler u-cather of fall is not a necessary condition. If successive planting:: of cosmos arc made in the greenhouse during the latc u-int'er and early spring months, ninintaining a uniform temperature throughout , the planting made after :I cwt:\in tlnte 11-ill fail to blossom promptly; hut, on the cont,rary,will cwi~iiiiie t o g i ' o until ~ the f'ollo\\-ingfall. thus floivering at the iisiial season for this specics. This cwrioiis i,c\-ersnl of heliavior with advance of tlic season cannot he nttrilwtcd t o c~liangcin teinperatui~e. Some other favtor is responsible for thc 1ailui.c of rosnios t o hlossom during the summer months. In this respect the hchnvior of (~osinosis jnst the opposite of that observed in irilc:ir that the time of flo\\-cring and fruiting of many plants is linlied inseparubly in somc ivuy ivitli thc ativnncc of the season, and iiecemuily there must lw ionic estcrnal factor ivliicli maintains this relationship. TYith temperature eliminatetl. there remains one change from season t o season \rhic~h proceeds with great i~eg~ilnrity,--namcl\-:the change in length of day and night. -kt Washington, D. C., t h e time \ictwtcn sunrise and siinset ranges froin nearly 13 hr. in late .Tunc to :ihoiit 94 h r . a t Christmas. 'l'o determine Tvhethrr this rhange in the leiigth of clay is :I. (~:iiiwof regularity in t h e time of flon-ering and fruiting, a series of e s p e i h o n t s \v:w made in which :i number of plants \vcre clnrkened for n purtion of thc day tiiii.ing the long days of summer. The results olitained ]\-ere i~emni~knhlc.'l'lie plants no longer persisted in their usual habit of deferring the floivcring peiiotl till :I p:iificiilar time of the year had heen reached. The normal scnson:il periodirity \vas hroken up completely. 'I'hc experiments included :I large variety of plants h o t h wild and cultivated, nntl it, \vas found that, reacation t o diffei*cnoc in the length of the (la\- is of very \vide occurrence (T,17. 381). 1he response of the pltints to the nrtiiicial shortening of the tlaylight pcriotl \vas prompt ant1 c.lenn ( # u t . 12iloxi soy heans which germinated 3Iay I T \\-ere allon-ect to receive 7 hr. of light daily, beginning N a y 20. These plants were in blossom in 2(i d ~ t j - ,~~ v. h e i ~:I ~siiiiil:ii. i . ~ lot of plants exposed t o light thi~oughniit the day required 110 clays to flower. This variety of soy beans, n-hich ordiiiarily f l o ~ v e in i ~ Septemhcr, even though planted in M a y , \vas forced into hlossoni in ? .
HEREDITY d S D E S V I R O S J I E S T .
I1
Xi3
,Tun(,, simply liy shortening the daylight period. I n further tests it was found that :i daylight period of 12 hr. ' i n s as effective a s the 7-hr. period in forcing t h e flowering of the soy beans. It is easily seen, therefore, n-hy this variety of soy t x m s oidinarily does not. flou-er till September, for i t is a t that time that the length oi the day is reduced t o 12 hr. (T,p. 383). One scarcely expects to see chrysantheniums in bloom in midsummer; hut these typical fnll-flowering plants are rendily forced into blossom during the siimmcr hy reducing the length of the daily light period to 10 hr. In the light of these esperiments there is no longer :inj. elenirnt of mystery c~oncwningthe fact that when plnntings of cosmos :ire made :it successive tlat e:, in c:ii.l~.spring ii point i,< reached at rvliicli tlic plniitiiigs s\ving oi-er sucltlcnljfrom flcrwering in the spring to flou-ering in the fall, Cosmos hrgins to flower in the. fall \\.lien t h e length of the day lins tlecre:isecl to iilwut 12 hr. (sunrise t o ,sunset j and is no longer able to floivcr in the spring a f t e r the 3:iys hecome ni1ic.h i n excess of 12 hr. in length ( 7 , p. 383). Under ordinary conditions spinach cannot be gro~vnsuccessfully for table iibe during the summer months, 1)ecnuse it goes quiclily t o seed instead of forming tlic desired rosette of large IenT-es. This 1ieh:iTior has been generdly attrihuted to high tmiperature. It is qiiite ti,ue that ivithin suitable limits an increase in tcrnpernture. a s n i d e , speeds u p plnnt development ; nevertheless, esperiments hn\-c sho~vnt1i:it spinach xi11 produce an excellent rosette in siunimcr if the light pcriod i,? i d u c ~ e dto 8 or 10 hr. I-nder these conditions the flo\vering stems are i i x i l i l ~i o ~ form, or, a t least, their appearance is clclayed greatly (i',p. 389). 'l'hcre i q n large group of plants which nre hrought into the flon-eringand fruiting strxges of development lwcnuse of tlic length of the clay LIS spring advanceinto summer. &Isn matter of ronvenience in discussing flon-ering and fruiting actiyitie.. this group may be spoken of as ~*long-tlayplants." in contrast to the group previoiisly tliscussed, v-hich are forced into flon-ering and fruiting by the slioi.tening of the days in the fall :ind may therefow lie cqallecl "diort-day plants. TYhile :I. n \\-hole there :IIY sharp contrasts bet\\-een t h e tI\'o groups, there are mnny plants it-liich may perhaps he reg:irclcd n s occwpying nn intermediate position. There is, in fnrt, no hard :ind fast line bet\\-ern these tu-o classes of plants. T1ie1.r.:tie some plnnts, indeed, for \vhich it is possible t o provide a daylight periotl too long on the one hand and too short, on the othei*,l o induce flon.ering : ~ n dfruiting ( 7 , p. 390). I n temperate regions most plants have ti comparatively short period of flon-ering m d fruiting each year. though plants differ in the length of this period. I n hon-ever? this period of reproductive activity continues through ths, and plants behaving in this ninnner are linoivn ns everbloomers or everhearers. I n the preceding discussion the fact is brought out that most tend to continue the purely 'i-egetntive form of development as long as the ~ ' of e ;I certain length, \~-hileuntleraiiotlierlength ofdnj- 'i-egetati'i-edevelopment gives way to floiveiing and fruiting. S o t all plants are equally sensitive. 'ion-ever. t o changes in the length of dny. K i t h these t\vo funtlamental facts in mind it is easy to Iinclerstand the rehtion s f t h e length of day to the condition in "
~
434
V ILDEH D. B.ISCKOFT
plants knon n as ev.cr\>loomingor e7 erhealing. If Biloxi soy 1)eans or cohnlos plants are suhjectetl t o ai1 artificially hhortened period of daylight of 9 or 10 hr. in midsummei, the purely I egetativc iorm of activity is promptly checketl i l n d flou ering and fiuiting iollov qiii(ak1y. Su1)jecting Hiloxi soy ]leans t o n -oniewhat longer daylight pel iod of 12 hr. in mid-ummer ha3 i ~ e ~ u l t einda considel ahl) larger stature for the plants, :ind I d o ~ m i n gh a i heen (*on-iderably delayed Furthermore, lengthening t h e daylight period from 10 hi. t o 12 hr. has G l o u et1 don n markedly the rate of development of the pods, ant1 consequently the ripening of the seed. In othei \\ oidr. \\ e have heen working in the direction of vegetiit i r e activity and to :i g r w t e r 0 1 ' le.;* degree a u a y from the condition of free nntl rapid flowering, ripening of seed, and fruit death of the plant>. This suggested the possibility of a nice M a n w or adjustment betneen the vegetative antl the reproductive phases of development I\ hich n-ould expre>\ it-elf in more or lew prolonged everblooming and everhearing tmclencie>. From this Tien-point the everflowering tendency i m p l y memz the ability t o continue h t h vegetative antl reproductive activitie> more or le+ surcessfully together. T\vo features of the relationqhip hetu ern length of day a i d everblooming w e oi qpecial importancle: ( 1 ) the occurrence in different latitudes of the proper range in length of (lay continuing over a sufficiently long heason and ( 2 diferences among plants in their qensihility t o rhanges in length of day. I n the case of those plants which are readily changed from the vegetative t o the reproductive form d activit?- by zt change m the length of the day, the proper intei mediate length of day favorable to both forms of activity must per-ist over ;t zufficiently long period it \\e may expect the everblooming habit to appear. .I* one advances from the poles touard the equator tmth the reasonal and the daily changes in length of day dccrea-e, till a t the equator a ti.;ecl day-length of 12 hi.. prevails the year round. I n extreme northerly or southerly latitudes, on the other hand. there is a con-tant and relatively rapid change in the length ot the day. I t is clear that under these latter conditions the tendency would he for plants t o he swept rather rapidly through the particular range in day-length 11hich would permit the vepetatil e and reproductive activitiez to proceed aimultaneouqly. Therefore, thew I\ oultl he little opportunity for the evert)looniing habit to develop in f a r northerly or yoiithcrly regions, cven during the open growing beason. In theye rcgion~c\ erflo\vering \\ ould he cwnfined most1)- t o those plants which happen not t o Iw pai~ticularlysen-itive to changes in the length of day. For plant.; having a daylight requirement for both groving and flonering ranging roiintl 12 hi, condition.; a t the equator \voiild he ideal for the development of the everflouering habit l\ a matter of fact, everflowering is a characateristic feature of plant life in the Tropics, and thii form of reproductive activity steadily heconies les5 prominent as we a d ~ a n ctoit ~ ard the poles In temperate regions comparatively fev plants can he regarded a5 typical everbloomen. By suitalde cont rol of the daylight period the explanation of everflou wing offered above can 1w tested directly. With a daily light period intermediate betn een that required l o induce free flonering and t h a t ivhich favors vegetatiw ~
HEREDITY SiYD ESVIRONMENT.
I1
465
development exclusively a given plant should continue to flower for a more or less indefinite length of time so long as the light period is held constant. For example, one of our common wild violets iT'iola papiliorzacca) after a brief period of \\.inter dormancy renen-s its activity in early spring liy unfolding new leave:;. -1little later the familiar blue spring blossoms make their appearance. -1s the longer days of >lay and ,June come on, vcgetative activity is inchreased; there is greater development of foliage leaves? and the chnracterist ic* liliic 1110ssoms disappear. Obviously these plants are approaching H strictly vegetative form of acAtivity. In reality, hon-ever, floivering in the hotaniral sense does not reasr, for in place of the showy spring hlossom a peculiar type of flo\\-er is procliiced henenth the leaves which docs not open, though it produces seeds. This appear:: to be a case of fine adjust,ment to thy-length, for evidently the peculiar summer type of floivers represents a stage nearer the purely vegetative condition than docs the richly colored spring blossom. IT'hen these plants were allon-ed to i w 4 v c only about 8 h r . of light daily they continued to produce only the blue spring type of blossom and made but little 1-egetative growth. Surprising as it may seem, by this method the plants were kept in bloom constantly from March till Sovember, Ivith a minimum growth. Flowering finally ceased only because the clnylight in December fell below the minimum requirement, so that the plants were forced into dormancy. In short-day plants the purely vegetative tlevelopnient is favored by long days, a n d flowering is initiatecl when the days have heen shortened sufficiently. We shall non- consider the behavior of iris, which floivers during the long daysof May and .June. Plants taken from the field in autumn started into growth a t once and floweredwithin 55 to 60 days in the house, where electric illuminationwas used from sunset until midnight to supplement the short daylight period of the winter season. I n t'he control house the plants were practically dormant vegetatively until l\Iarc+hor April, sinc3e they shon-ed practically no growth, and flowers did not appear till June. In spite of the warm temperatures in the control greenhouse, this plant \vas unahle to flower in n-inter hecause the clays were too short. In the same ~ v a ythe common goldenrod, which regularly hegins flowering in .June, W L I S readily forced into flon-ering in winter hy the use of electric light, ivhcreas without electric light no floivering stem \vas formed, even after a n esposure of several months t o short-day conditions. Spinach planted in tlic house provided with electric' light in Sovember \vas in bloom in G week::, while in the control house the plants remained in the rosette stage throughout the Ivinter. Kithin suitable limits of temperature and ot'her important factors in plant growth, there ~ v o u l t seem l to be no reason why almost any plant may not he made t o flower and fruit at a n y season of thc year in any region. By shortening the daily light period through the use of dark chambers or lengthening it by means of :irtificial light, reproductive activities may he induced almost a t will. With proper knowledge of the specific requirements of each plant, thercfore, the florist should he able t o f'orve flowering at any desired time of the yenr. It has been possible to secure escellent flowering specimens of iris in mitlivinter and of chrysanthemum, poinsettia. and other plants in summer by utilizing thesc principles.
I n the same \yay Ivild 1-ioletshave heen kept in the everhloomiiig stage as long as nine months. 'The principles involved are so simple that anyone interested in plants can easily ohtain instructive and cwnrincing results. Garner and Allard sny (T,p. 400): "It may be of interest t o c i t e n speciiic iiist:Lnw in which the (lay length effect has been npplied t o t h e solution of :I 1xxctic:iI probleni in tohncco culture. Several years ago n new type of tobacco its tiiscovered in Southern JInrylnnd. Cnder suitable conditions this t y p e grows t o an unusually large size, the plant in some cases producing more t h a n 100 leaves; hence the naiiie 1Inryl:ind Mamniotli hy which this v w i e t y is known. Because of its high yielding capacity this r:iriety is g r o ~ nwith gre:it success i n Southern Mar A peculiarity of this toh:ic.co is that either it does not flower :it :ill in t h e ticld in 1Iaryl flowering occurs so 1:itc in the senson th:it the seed does not nxiture. Fnrniers, therefore, cannot obtain seed by t h c usual methods. I t \v:ts found, however, t h a t Mammoth tobacco flowers very rendily in tlic greenhouse under t h e natural day length of winter, whereas artificial lengthening of t h p d:rily light,prriotl p i ~ v e i i t flowering. s T h e plant does not flower i n t h e field in lI:iryl:iiid, bcc:iuse t h e suninicr tlnys :ire t,oo long. The problem of securing seed is easily met by gro\riiig t h e p1:ints i n Southern Floridn during the \+iter, for under these conditions thc 1I:immotli fioivcrs :inti fruits much the snnie as t h e ordinary varieties of tobacco."
M y attention IYW ( l i x i ~ nt o thc \vod.; of (;ariier niicl his collaborators by n hook of Rutheriord I'lntt. T h i s ('11 lT70r/(/. ('huptcr 11 is entitled "The DayLength Timetable oi Floi\-(~rs."1 think th:it I I r . I'lntt overdramatizes the ~vorl; of Garner ti l i t . P h t t says ( I i . pp. 9 7 - S ) : "Recently I R;IIY i n t rwst ing gi,:iplii(*cIi:ii,! s shoiviiig lion- ni:i~iyspecies out of one huiidrctl populnr natiye fion-cring p1:ints :irr i i i i)looni c:ich c:ileiiti:ir ivceli from 1Iarch through October a t t h e wild f l o ~ e rrcserrntioii of t h e 3Iissouri I3otnnic:il G:irden, G r m d Suninlit, 310. T h e number uf tiiffrrrnt sprcies in lilooni in:iltes :I pe:lli :irountl the first of May, then for :L lveek or t w o tlr(ip5 i,:il)idly. :inti i,ises ;ig:iiii for :inother peak in niidaumnier. These tv-o penke of bI(~oniing: i i ~vonst:iiit yc:ir :iitrr yc:ii.. Wheii these c1i:irta :ire compctreci w i t h charts of the riiinfall :inti 1 cnil)ci~:itulcoi tlic s:inIr ~ x ~ r i o ~it l is a ,seen that there is n o relation betn.eeii the tivo. T h c hlooniiiiy is sc:ircely :itfected l>>-v:iriatiuns of r:iinfoll mil temper:itiirp. For inst:iiice. oiie yenr :it t h e inideummcr hlooniing pe:ili there n-:is a fierce drought, :inti t h e rainfnll line toucheti h o t t o i n . R u t thr flon-crs d l bloonied 011 their fixed schedules."
I'htt is more tlst remc than C;ariicr aiid -llkird, from \vlioni he is supposed to h getting his information. Gnriier and AUlarclstty (i,1). 378) that "plant development' may be rettucietf in tlic spring by cool \veatlicr, and a t times:, drought or excessive raiiifall may intcrfcre ; h u t , in general, flo~vcrand fniit are produced regularly in these seasons in spit c of temporary tlistiirk~ances." I ani not saying tlint l'latl is i~roiipin the c t w s vited. He m:q h a r e bee11 right, and I coiiltl not 1)rm-e i t it' hc \Yere I\-rong. I do knorv that what I iinderstancl him to c~laimis not aliv~iysso. In the qxing of 1948 the Japancw cherries bloomed :it \\~nsliingtonin March, id that is about a iortriight ahead of schedule. Consccliiciitly thcrr is at least one factor \rhic.h Platt has not taken into consideration. 1-nder the circumstances it docs not make any differenw how many times thc cherries liavc hlossomed on schedule, though that might malie it easier t o discover \\.hatj the disturbing f x t o r \vas. -111 the same, Platt's
HEREDITY . I S D E S V I R O S M E S T .
4Gi
I1
chapter is interesting t o read and one rather wishes thnt it hutl lwei1 as sound as it as interesting. One wonders about tlir other c*hn,pters. I n an article published in 1938. _Illarc1(1) inti*iduwsa f o u r t h calnss of flo\verinp pla n t s . “On the bnsis of tlicxir flii\vcriiig beh:ivioi, :is r,rlatctl t ( 1 or clcpcndr~ntu p o n leiigt I i of tl:i!.. i t h:is long tieen recognized th:it plants may be gi,oupril into t h r r e cl:iases-thr long-d:iy plants, t h e stioi,t-day plants, and indeteimin:ite p1:irits. i , r . %tliosc insensitivc t o length of tiny. The long-day plants m e induced t o flower, or flower nioi’r quickly, :LS t h e clays nre lpngthenec! :ind the short-day p1:tnts :is t h e days are shortcneti; tlic irit1~termin:iteplants linve liecn so c:illed i1ec:iuse their usu:il flo\vering :ippc:ira to I w l i t t l r i,cl:it ctl t o :iny p:irticuIu~1ci;gtti of tl:iy i n the n:itur:il terrestri:tl arrLtngenient . .‘Typical long-day, shoiT-d:iy. and inctetel~niifi:itep1:iiits h:xvf been found i n :ibund:ificc. Flirther. studies of t h e i)eli:tvior of tlifYei,ent pl:ints in i,el:it i o i i to I(~iigt1iof d:~yhave shown th:it still other plants exist thnt flower n.ithiii :i tlrfiriitr r:iiigr of lt7rigtIi of h y , producing floners less readily o r ’ i)ecoming sti,ictly veget:itivc tvliclii the k i y s : i i ’ ahoi~tciiedo n the one 1i:incl or sufficiently lengthened on the other. t>rh:ivioi.of these plants in relation t o length of d:i!- is s o instrucrivc, they h 1 - e been ternled :is “inter~~nedi:~te” t o distinguish them f i , o i i i tlic long-d:iy. t h e s h o r t - t h y , :ind the indctcriiiin:ite plants. “Relatively few p1:tnts showing interlnediatc flowering belinvior 1i:~vr been found. Climhing hemp\veetl (.Ilikania scanderis (I,.) Willd 1 uppe:irs t o tie n typical exnmplc of this c1:iss. u i i t l several other wild plants, including t h e iiutive \vild l i m n (Phascoliis poZystachyi/s (I.. 1 (BSP))a n d the wild boneset (Eicpatorircnr t o r i c y c c u i c n i (slit>i,t)), likenisr show more or less definite tendencies towwcl t h e same behavior. -1variety of tropical sugarcane (28S.G.292) of tlie species S a c c h a r i i t u spontnneum L. gives evidence of liaving the sharpest a n d 1 1 : ~ rawest flowering range of a n y plant yet found in this group. . . . ‘..llikaniu scandens flowers very poorly in response t o length of d : ~ pt h a t are 12 hours lung or less, and flowering h:is practically ce:ised when the t1:iys Ii:i\-e l i e e n lenthened t o 16 hours or more. “Phaseolus polystacchzis is near its flowririg liniit wlien the days :ire reduced t o about 122 hours or less. Esperiments indicate t h a t the plants floiver most readily ivith 13 t o 14 hours of daylight, and stion- :I delay in flowering when the daylight exceeds these values. ‘.The wild S e n Guinen sugarcane 28S.G.292 of the species S a c c h n r ~ ( mspontancicv~ L . tins shown t h e n n r r o w s t flotvering response of any pl:irit yet studied. Test with dnily light ieriotls ranging, at 1 hour intervals, from 10 to 14 hours. and Fvith the full length of d a y . a t LVnshiiigton, D. C.! revealed t h s t t h e flower buds were formed only when t h e plants were iffordetl 13 hours of light each day. T h e flowering r:lnge for thi. species. therefore, lies Pom~nliPrebetTveen 12 a n d 14 hours of daylight .” R c i m t l v Holdsn-orth and S u t m a n (11) have piihlished wponues in a strain of Orobajichc nii,ior..
:it1
Lirticle on flo\vering
**.Ininteresting case of the depentience of flutveririg on lciigtli of c h y hus been found ii; ‘ i ~ d ~ a / i c l minor ce groning o n red clover. In tlie first p1:tcc. d a t n ol)tained by one of us ( P . lassas red apples antl red pears. 9. Thornton Platt says that tlie retl autumn coiors of leal-es d o n o t non- tlepencl on frost, but probably did in some prehistoric age. 10. Cosmos. chrysanthemums. and fringed gentians are short-day floi\-ers. Red clowr, iris! and goldenrod arc long-day flon-ers. Prutcilln rulyaris and tomatoes :iw indeterminate flon-ers. Il1l’i;at~icr .scajzilcizs, P1iaseolit.s polystacclziix, m t l E )!pafor1‘iI t?? torrcga ti i i m are int erniedint e A oil-ers. 11. Kithiii suitable limits of temperature and other iniporatnt, factors in plant gron-th i i seeni.5 probable that nlmost any plant may be niatle to flon-er and f r u i t :it an?- season of the year. 12. It is not laon-11 \\-hat valises the nppeainnce of ivhite flon-ers of Gf,titia)icr 1it 1 rii r is. 13. The fact that rcrtain a p p k and most pe:w d o not 1111’11 red \\-lien ripening i n sunlight is due to the absence 01’ inefYectiveness of t h e ~ n z y m e sn-hich m:il;c flaJ-ones photosensitive. This has not !-et lieen shoum experimentally. hou-n that :i 4 t a h l ~re;tricted diet may increase the life of ;I lvliite rat from a noinial of almut t w o years 10 a inasiniiim of 1456 days. 1.5, The development of .Jersey nnd Guernsey cattle a n d of Shetland ponit>i. vitetl hy lIcCay, is apparently an effect of heredity antl not mi\-ironnient, thouyli i t involves a n adaptation t o environment.
472
MARTIS H. LITTLE .4ND ARTHUR E. MARTELL
16. The regreening of oranges in Florida is an effect of environment. 1’7. The flowers of Sweet William come nearly white vhen not exposed t o ultraviolet light. 18. The number of four-leafed clovers in a patch varies with changing environment, increasing in hot n-eather. REE’EKESC .kLL4RD: J. Agr. Rese:tVch 57, 10 (103Si. ALTARI)A X U G A R W R :J. .igr. Research 63, 305 (1941 1 BAXROFT:J . Phj-s. Colloid Chem. 51, 1083 (19471. RRIUGE:1Ll:yrian S p r i n g , 1). 135. Little, I3rowri :iricl (:omp:tri>-, Boston, AIassnchusetts (19351. ( 5 ) FLETCHER: Proc. .1111. FIo1,t. Soc. 26, 191 (1029). (6) GARSER: Rotari. l l c v . 3. 268 (1937), (T) GARSERASD ALIARU: 1-carbook of the I:. S . Department of‘ Agricidhre, Washington, D. C. (1920). (8) GARNERA N D ALLARI):,J. .ig. Research 31, 555 (1925). (9) HEIN:Bull. mens. S O C . linneenne Paris 2, 932 (18911. (IO) HILLES:Vermont Agr. Espt. Sta. Bull. S o . 103 (1903). ( l l j HOLDSWORTII .&si) SCTXIAS: S a t u r e 160, 223 (1947). (12) H o u s ~ Wild : Florcem, p . 205. The 1I:~cmill:~n Company, S e n York (1935). (13) Reference 13, p . 220. (14) hIcC.4~:Am. ,J. Pub. I I e d t l i 37, 321 (1947). (15) ~ A T T O : u r FlorwritLg It’orld. Dodd, Meat1 anti Company, S e n Tork (1947). (16) Reference 15, p. 179. 117) PIATT: This Green Il.or./ri. Dodd, AIcntl xntl C‘ompnny, S e w I-ork (19421. (1) (2) (3) (4)
IZ .UIAS SPFYTK.~( )F 11w Depaitiiit
nt
rts (li
11 IxrmE,?
(‘hc
ittiall
y.
ClrriX
.mrr.iw
\HTHPR I; MARTELL f * n i i t rsitu, I170rcester,
Massachiisefts
Iieccii cd J i i l i l 17 1948
Since acetals contain t u o ether lmhages utt:tched t o the yame carbon atom, it \vas decided that it < t i d y of the Etaman spcctra of a series of acetals would be of interest. Hibbcn’i hihliography ((i),\\ hich coveis Raman literature up to 1939, and a search of thc literature iincc 1939 iwealed that no paper has been puhliyhed cwncerning the Itaman spectia of thew c*ompoiinds. hlthough it a- clrritlctl t o prrparc -wcixl homologoiis ~ r i e sof acetals, it was found that somc of thc wrtal- (wild not tw prepared ti\- the usual method, as described by X d k i n ~and Sisben (4). ‘I’hc preparation of these acetals by anothci. method ha\ h e m po-tponecl t o ii late1 clnte I t \ \ a + also found that 1 lbstractcd from ‘L dissertation prcsentetl lj\ AlaitLri I€ 1.ittlc t o the E‘iculty of Cltlrb I-nivcrsity in pnrtial iulfiilnic~ritoi the rcquiic~nicntsfor t h o tlcgrcr of Iloctor o f I’h1losoph.r , h u g u s t , 1946 I’rewnt addrebs I>ep,ii tnient of (’hemisti\ I ~ i r o i i( olieyc, Schenectatiy. S e w Tor6
