GROWTH AND TRANSPIRATION OF TOMATO IN RELATION TO NIGHT TEMPERATURE UNDER CONTROLLED CONDITIONS

Transcription

1 635.64: :581.11: MEDEDELINGEN VAN DE LANDBOUWHOGESCHOOL TE WAGENINGEN, NEDERLAND 59 (4) 1-6 (1959) GROWTH AND TRANSPIRATION OF TOMATO IN RELATION TO NIGHT TEMPERATURE UNDER CONTROLLED CONDITIONS by A.A.ABDEL RAHMAN 1 ), J. F. BIERHUIZEN 2 ), P. J. C. KUIPER (Labratry f Plant Physilgical Research, Agricultural University, Wageningen, Netherlands, 189th Cmmunicatin) (Received 13.3.'59) 1. INTRODUCTION The effect f a cnstant air temperature n grwth and water requirement f tmat was previusly investigated. It is f special interest, hwever, t study separately the effect f day and night temperature since literature in cnnectin herewith is nt very extensive. It is als f imprtance t investigate the relatin between transpiratin and grwth as influenced by night temperature. 2. MATERIAL AND METHODS Tmat seeds were swn in wden bxes and the seedlings transplanted 12 days afterwards int small metal cntainers, 20 cm high and 10 cm in diameter. Each f these cntainers was filled with 2 kg f lamy sil. Fifteen days after transplanting, the tmat plants were all expsed t the same day temperature (25.3 C) and, in series f fur plants, t different night temperatures (25.3, 20.0, 15.6 and 9.2 C respectively). During 12 hurs in every 24 hurs the pts were in a cmpartment illuminated by "daylight" flurescent tubes at an intensity f 7.6 x lo^rg.sec.^cm -2 0 sphere, measured with a spherical radiatin meter. Then each set f fur plants was transferred t a dark cmpartment, kept at a cnstant temperature fr the remaining 12 hurs. The mean relative humidity f the air during the whle perid f the experiment was apprximately 60 %. The sil misture was maintained between 100 and 80 per cent f the maximal available water cntent which range previusly had been shwn t be ptimal fr grwth (1). The water lss was measured each day, by weighing. Once every week, the sil in the pts was cvered with plastic sheets fr 24 hurs in rder t measure the amunt f water, transpired by the plants. Fr further methdical details see ABD EL RAHMAN and BIERHUIZEN (1). The height f the sht was measured *) LecturerinBtany,Faculty fscience,cairuniversity,egypt,guestwrker at thelabratry fplantphysilgicalresearch,agricultural University,Wageningen. ') Institutefr LandenWaterManagementResearch,Wageningen. 1 q\ 2> \S^

2 nce a week, during the experiment (28 days). At the end, fresh and dry weight f sht, ttal leaf area, number f leaves, and dry weight f rts *) were measured. 3. RESULTS AND DISCUSSION A. Grwth measurements Sme investigatrs have discussed the effect f night temperature n the grwth f plants. Accrding t WENT (5), the ptimal temperature fr stem elngatin in yung plants is 25 C during day and night. VERKERK (4) mentined that under fauvrable light cnditins the stem grwth increased with increase f day and night temperatures. Under lw light intensities this was less bvius. LOOMIS (2) bserved that grwth is ften crrelated with temperature during the night, and with the relative humidity during the day. THOMAS (3) fund translcatin f sugar t increase with a decrease in temperature. Because f this, 18 C was cnsidered a mre favurable temperature than 26 C. Lwer temperatures gave an unfavurable effect because they decreased t much the rate f ther prcesses, invlved in grwth. Accrding t WENT (5), s called thermperidicity in tmates is due t the interactin f tw prcesses, ne ccurring in the dark, the ther in the light, f which the dark prcess shuld have a much lwer temperature ptimum than the prcess in the light. In the present investigatin grwth varies in relatin t night temperature as is shwn in plate 1. The height f sht shws a reductin t 63 % with the night temperature falling frm 25.3 t 9.2 C (fig. 2) which was due t a difference in rate f elngatin (fig.1). After seven days, the difference in height / s xm5.6 C '- # 9.2 C D 20 C Numbtr r days FIG. 1. The rate fstem grwth f tmat plants at different night temperatures. between the varius treatments was nt significant, it increased gradually with age (fig. 1). The ttal leaf area varies irregularly with the different treatments. It seems that night temperature, in the range f temperatures studied, has nly a minr effect n leaf area. The dry weight f the leaf decreases regularly - thugh rather 1 Dry weight f rtswas nt measured in the experiments, described in (1), furthern it has always been recrded. 2 Meded. Landbuwhgeschl, Wageningen 59 (4), 1-6 (1959)

3 S t - e * 80 - " , t - «80 - ; 60 - « Î 20 - "E t * 60 - ï ï' 20 - t - * sl " 40 -! 20 - lil 1 II II II Night ttmp«ratur«( c) FIG. 2. The variatin in height f sht, ttalleaf area, dry weight f 1 cm 2 f leaf and gain in dry weight f sht at different night temperatures. The values are expressed as percentages f maximum * 0.10 H 0.08 = Night u ( C > i FIG. 3. The variatin in dry weight f sht, f rts, and f the rati f rts t sht at different night temperatures. The values are expressed as percentages f maximum, except the rati f rt t sht. little - with decrease in night temperature, it shws a reductin t 85 %in the night temperature range frm 25.3 t 9.2 C (fig.2). The variatin in ttal dry matter prductin f the sht des nt depend primarilynthe variatininleafarea, butmainlynthegrwthfthestemand the dry weight f the leaf. The dry weight f the sht decreases frm 100 % t 98,76,and 73 % in experiments at night temperatures f 25.3, 20.0,15.6, and9.2 Crespectively.Thegainindryweightf rtsvariesnlyslightly atthe varius treatments (fig. 3). It isevident, frm these results, that lw night temperature favurs a high rati f rt t sht (fig. 3and Table 1).The rise in night temperature frm 15.6 t 25.3 Cisaccmpagnied by a reductin in the rati frm t (r t abut 73 %). The difference in rati between 15.6 and 9.2 Cis insignificant. B. Transpiratin During the last seven days f the experiment, transpiratin was measured during day and night separately, while the btained data were calculated per unit leaf area. Itisevidentfrm fig. 4 and Table 1 that areductin in day transpiratin rateissignificant nlyinplantswith anight temperature f9.2 C.The night transpiratin rate at 20.0 C night temperature is nly 56% frm that at 25.3 C. At still lwer night temperatures, the transpiratin rate remains almst thesame.thelargedecrease innighttranspiratin bservedmaybedue t a decrease in the vapur pressure deficit at the lwer temperatures. Since the transpiratin rate during the daywasrughly 5 times that duringthe night, the mean transpiratin rate per 24 hurs shwed a significant reductin nly at 9.2 Cnight temperature, viz., t abut 76 %. Meded. Landbuwhgeschl, Wageningen 59 (4), 1-6 (1959) 3

4 TABLE1.Effect f nighttemperaturengrwth,transpiratin and waterrequirement ftmat Night temperature in C Height f sht (cm). Mean length f interndes (cm) N. f leaves 26.4 ± ± ± ± ± ± ± ± ± ± ± ± 0.2 Mean length f mature leaves (cm) Mean area f mature leaves (cm 2 ) Ttal leaf area (cm 2 ) ± ± ± ± ± ± ± ± ± ± ± ± 14 Mean dry wt. f 1 cm 8 leaf surface Gain in dry weight f sht (g) Gain in dry wt.f rt (g) ± ± ± ± ± ± ± ± Gain in dry weight f sht + rt (g).. Rati f rt(g)sht(g) 1.88 ± ± ± ± ± ± ± ± Mean transpiratin f a single plant (g/day). Transpiratin by day (g/dm 2.h) Transpiratin at night (g/dm 2.h) Mean transpiratin rate f the whle day (g/dm 2.h) 31.8 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Water requirement sht) Water requirement (sht 512 ± ± ± ± ± ± ± ± 9 Althugh during the peridf illuminatin (representing theday perid), the plantsbelnging t different treatmentswereplaced in achamber at thesame air temperature (25.3 C), the sil temperature in the pts expsed t lwer night temperatures required sme hurs t attain the same temperatures as thse cntinuusly expsed t 25.3 C, and the mre s, inasmuch as the difference in temperature waslarger.thismaybe f cnsiderable imprtance. The temperature f the sil in the frmer case was 24 C. The sil in pts expsed t night temperaturres f 20.0, 15.6 and 9.2 C required apprximately 2, 5 and 6 hurs,respectively, t arrive at a sil temperature f 24 C (fig. 5). Of curse, it is als imprtant that the sil subjected t a lw, night temperature tk a similar perid f adaptatin t the lw temperature. It is clear that thediscussedeffects have thelargest amplitude at thenighttemperaturef9.2 C.On thether hand,relativelyquickly the temperature f thesil is withinnly afewdegreesfrm that f the air. As the sil in the pts was 20cm deep, it represents abut the layer f sil in which the greatest numberf the rtsgrw. It is evidentfrm these data that the night temperature gives a large after-effect n the day temperature f the 4 Meded. Landbuwhgeschl, Wageningen59 (4), 1-6 (1959)

5 Ä 100 c 80 O >, 'Z 60 ' i "0 % c 80 ï ~ 60 z ä 40 «20 '00 ï c 80 a.2 ~ S % _ c '00 sl 80 I j i 20 II i lu im il M - m Night temperature ( C ) FIG. 4. The variatin in day and night transpiratin rate, and the transpiratin rate during the whle day at different night temperatures. The values are expressed as percentages f maximum. /,',,^, ' / - i / / / -,- ;... -;;'---" N.T C N.T C N.T. 9-2 C i i i i i 1? Time hurs FIG. 5. The change insil temperature f pts transferred frm thedifferent night cmpartments t the day chamber at 25.3 C, at 10 am. S g 100 Z«80 r - M. 60 * 2 40 % 100 II «E % 60 ; 40 S 20 t t 40 I 20 - h M II l Night ttmperaturecc ) FIG. 6. The variatin in ttal waterlss by transpiratin, gain in dry weightf sht and water requirement, at different night temperatures. The values are expressed as percentages f maximum. sil.sincethe latter has a nticeable effect n the rate fwater absrptin, the night temperature may influence the day time transpiratin by means f the sil temperature. C. Water requirement The water requirement is determined by calculating the amunt f water transpired in g per g dry matter prduced. Accrding ttable 1 and fig. 6 the ttal amunt f water transpired, and the gain in dry matter prduced at the different treatments shw apprximately the same prcentual change. The difference in night temperature frm 25.3 t 9.2 C is accmpagnied by a decreasein the ttal water transpired t 68 %,and in the gain in dry weightf sht t 73 %.Asthe difference between the twpercentages is nt very great, the water requirement des nt shw appreciable variatin. Meded. Landbuwhgeschl, Wageningen 59 (4), 1-6 (1959) 5

6 4. SUMMARY AND CONCLUSIONS Tmat plants were grwn in metallic cntainers and, during a perid f 28 days,placed at a cnstanttemperaturef25.3 C under "daylight" flurescent tubesfr 12 hursinevery24 hurs. In thenight perid (12 hurs) nesetwas keptin thesamechamber at 25.3 C andthe therstransferred t cmpartments f varius temperatures (20.0,15.6 and9.2 C respectively). The grwth rate f the stem islwer at lwer night temperatures. A decrease in night temperature frm 25.3 t 9.2 C resulted in a reductin t 63 % in the height f sht. The ttal leaf area des nt shw a regular variatin, but the dry weight f 1cm 2 leaf shws a regular decrease t 85 % in the series with a night temperature f 9.2 C. The reductin in bth the height f sht andthe dry weight f leaves result in a reductin t 73 %in ttal dry matter f sht. The varius effects f night temperature may, at least partly, be ascribed t the time lag f siltemperature ccurring after lwer night temperatures. The transpiratin rate per unit area during the whle 24 hurs decreases significant nly with a night temperature f 9.2 C, namely t 76 %,whichwas due t a decrease in day transpiratin. The night transpiratin was apprximately ne fifth f that during the day, and decreases t 56, 52, and 50 % with a decreasein night temperature frm 25.3 t 20.0, 15.6, and 9.2 C respectively. The decrease in night transpiratin may be due t a decrease in the vapur pressure deficit at the lwer temperatures. Thewater requirement desnt shw a regular variatin in relatin t night temperature, which may be attributed t similar prcentual changes in transpiratin and dry matter prductin. ACKNOWLEDGEMENT The authrs are greatly indebted t Prfessr E.C. WASSINK fr his advice andencuragement.thanksarealsdue tmiss J. Bsfr technical assistance. REFERENCES 1. ABD EL RAHMAN, A. A. and J. F. BIERHUIZEN: The effect f temperature and irrigatin regime n grwth, transpiratin and water requirement f tmat. Meded. Landb. Hgeschl Wageningen, 59 (3), 1-14 (1959). 2. LOMis, W. E.: Daily grwth f maize. Am. Jurn. Bt. 21, 1-7 (1934). 3. THOMAS, M. D.: Effect f eclgical factrs n phtsynthesis. Ann. Rev. Plant Physil. 6, (1955). 4. VERKERK, K.: Temperature, light and the tmat. Meded. Landb.Hgeschl, Wageningen 55, (1955). 5. WENT, F. W. : Plant grwth under cntrlled cnditins. II. Thermperidicity in grwth and fruiting f the tmat. Am. Jurn. Bt. 31, (1944). 6. WENT, F. W. : Theeffect f temperature n plant grwth. Ann. Rev. Plant Physil. 4, (1953). Meded. Landbuwhgeschl, Wageningen 59 (4), 1-6 (1959)

7 PLATE 1. Grwth f tmat plants, kept fr a perid f 28 days at different night temperatures (Frm left t right: 25.3, 20, 15.6, and 9.2 C).