I, 0.1% · receiving 2500 p.p.m. of maleic hydrazide on either July 15 or August 2 were clean, bright, firm, and practically free from any evidence of sprout growth, even after seven

THE EFFECT OF PREHARVEST FOLIAR SPRAYS OF MALEICHYDRAZIDE ON SPROUT INHIBITION AND STORAGE

QUALITY OF POTATOES 1

D. R. PATERSON, S. H. WITTWER, L. E. W ELLERAND H. M. SRLL

(WITH TWO FIGURES)

Received July 9, 1951

Recent experiments conducted at Michigan State College have demon-strated that a preharvest foliar spray of maleic hydrazide 2 (13) induces astriking inhibition of sprouting and greatly reduces storage losses in onions(18), carrots (19), and sugar beets (20). Similarly promising results, hereinreported, have been obtained in storage tests with the Irish potato.

Materials and methods

Field tests were conducted on a productive Hillsdale sandy loam soilusing certified seed of the Irish Cobbler and Pontiac varieties planted May19, 1950, in rows 36 inches apart and with seed pieces at 12-inch intervals.

As outlined in table I, single aqueous sprays of 500, 1000, and 2500 partsper million (p.p.m.) of maleic hydrazide were applied to the foliage of theIrish Cobbler variety on July 15, August 2, August 11, or August 19. Plantsof the Pontiac variety were treated similarly on July 15, August 2, August11, or September 2. Treatments were replicated on rows 15 feet in length.Three-gallon hand sprayers were utilized in applying the chemicals and theleaves were sprayed until the solution dripped from the leaves. 'Dreft" wasadded at a concentration of 0.1% as a wetting agent. At the earliest sprayapplication on July 15 (approximately six to seven weeks before harvest)tubers of both varieties ranged from one fourth to two and one half inchesin diameter. Forty-eight hours after the latest treating dates, August 19for Irish Cobbler and September 2 for Pontiac, the vines of all plots werecut off; and the tubers were harvested four davs later.

Three controls were included to determine the relative merits of thevarious preharvest foliar sprays of maleic hydrazide (table I): 1. Successivesprays of 50, 100, and 200 p.p.m. of 2,4,5-trichlorophenoxyacetic acid wereapplied on July 15, August 2, and August 11. This treatment was includedbecause of favorable results reported by MIARSHALL and SMITH (10). 2. Apost-harvest treatment with the methyl ester of alpha-naphthaleneaceticacid as a dust formulation, "Barsprout" (American Cyanamid Company,New York), was used. Approximately the equivalent of 0.9 gram of the

I Journal Article no. 1270 of the Michigan Agricultural Experiment Station.2 Formulated as the water soluble diethanolamine salt of 1,2-dihydro-3,6-pyridazine-

dione, and supplied by the U. S. Rubber Company, Naugatuck Division, Naugatuck,Connecticut.

135

www.plantphysiol.orgon August 2, 2020 - Published by Downloaded from Copyright © 1952 American Society of Plant Biologists. All rights reserved.



http://www.plantphysiol.org



PLANT PHYSIOLOGY

TABLE ITHE EFFECT OF CONCENTRATION AND TIME OF APPLICATION OF PREHARVEST

FOLIAR SPRAYS OF MALEIC HYDRAZIDE ON THE SPROUTING OF COBBLERAND PONTIAC POTATOES SUBSEQUENTLY HELD AT STORAGE

TEMPERATURES OF 45 AND 55°F FOR SEVEN MONTHS.

Spray treatments Grams of sprouts per 10 tubers

Cobbler PontiacChemical Date Concentration

45°F 55°F 450F 550F

Maleic hydrazide 7/15/50

8/2/50

8/11/50

8/19/50

9/2/50

2,4,5-trichlorophenoxy-acetic acid

Barsprout (post-harvestapplication)

Control (no treatment)Differences necessary

for significance:5% level1% level

7/15/508/2/508/11/50

p.p.m.

5001000250050010002500500100025005001000250050010002500

50100200

42.59.00.017.514.02.0

27.515.07.0

58.539.526.0

110.028.02.0

39.012.512.0*66.037.030.5124.0108.596.0

88.59.51.0

10.53.00.0

40.022.50.0

145.594.551.5

110.550.03.0

40.03.50.0

68.024.526.0

156.5133.075.5

28.0 53.5 2.0 47.513.0 66.5 0.0 56.0

47.0 98.5 96.0 115.0

22.8 36.2 47.4 33.831.6 50.5 65.8 47.2

*9.0 grams removed from 2 tubers.

active ingredient was applied per bushel at the time the potatoes were placedin storage. 3. A third control received no chemical treatment.

Harvests were made and the yields were recorded on August 25 for theIrish Cobbler variety and on September 9, 1950, for the Pontiac variety.Immediately after harvest, duplicate 10-tuber samples were taken from thereplicates of each treatment and placed in paper bags. With the Pontiacvariety, individual tubers in all samples were labeled and initial weightsrecorded. One of the duplicate 10-tuber samples from each of the tworeplicates of all treatments of both varieties was then placed in a storagemaintained at 45 ± 20 F and the other at 55 + 20 F. On March 29, 1951,after approximately seven months, the potatoes were removed from storage,

136



PATERSON ET AL.: FOLIAR SPRAYS OF MALEIC HYDRAZIDE

photographed, weighed, and desprouted. The weight of the sprouts for eachsample of 10 tubers was determined.

Results

Harvest records showed no reductions in the yield, size, or quality ofpotatoes within a given variety resulting from any of the chemical spraytreatments. No tuber injury was evident. There was, however, a signifi-cant difference in the productivity of the two varieties with a mean acreyield of 268 bushels of U. S. no. 1 potatoes for Irish Cobbler compared with435 bushels for Pontiac.

The weights of sprouts in grams for 10 tubers after seven months storageat 45 and 550 F for the various treatments applied to the two varieties aregiven in table I. The relatively greater effectiveness of preharvest foliarsprays of maleic hydrazide as contrasted with 2,4,5-trichlorophenoxyaceticacid and the post-harvest application of the methyl ester of alpha-naphtha-leneacetic acid is apparent from the data. Especially striking were the dif-ferences in sprout growth at 550 F. Applications of 2500 p.p.m. of maleichydrazide four to seven weeks before harvest resulted in nearly completeinhibition of sprouting at both temperatures, while control lots sproutedprofusely. Some significant reductions in sprout growth resulted whenmaleic hydrazide was applied 48 hours before the vines were cut off. Greaterdormancy resulted when the sprays were applied on August 11. This appli-cation date was approximately two weeks prior to harvesting Irish Cobblerand three weeks before harvesting the Pontiac variety. Tubers from plantsreceiving 2500 p.p.m. of maleic hydrazide on either July 15 or August 2were clean, bright, firm, and practically free from any evidence of sproutgrowth, even after seven months storage (fig. 1). The data in table I indi-cate that a spray of 1000 p.p.m. of maleic hydrazide, if applied at the propertime, may be sufficient for the induction of dormancy. It also appears that1000 p.p.m. and even 500 p.p.m. of maleic hydrazide compare favorablywith 2,4,5-trichlorophenoxyacetic acid and the post-harvest treatment of themethyl ester of alpha-naphthaleneacetic acid for inhibition of sprouting inpotatoes.

Subsequent to the seven months of storage at 45 and 550 F, samples ofIrish Cobbler tubers harvested from plants sprayed with 2500 p.p.m. ofmaleic hydrazide on July 15, 1950, along with comparable non-treated con-trol lots, were analyzed for several constituents (2, 14). No differences werefound in percentages of dry matter, starch, or other acid-hydrolyzable poly-saccharides, total carbohydrate, or nitrogen (Kjeldahl). However, lowervalues were found for both reducing and non-reducing sugars in tubersstored at 450 F which had received the preharvest foliar spray of 2500p.p.m. of maleic hydrazide approximiiately six weeks before harvest. Simi-lar, though less striking, trends were also evident when tubers were storedat 550 F (table II).

137



PLANT PHYSIOLOGY

Although initial and final weights after storage of individual tubersthe Pontiac variety were recorded for all treatments, there was no signiicant reduction in weight losses when tubers and the attached sprouts weweighed together. Similar results for post-harvest treatments using t]methyl ester of alpha-naphthaleneacetic acid on the Irish Cobbler varielhave been reported by GANDARILLAS and NYLUND (8).

FIG. 1. Comparative sprouting of potatoes harvested from plants sprayed wi2500 p.p.m. maleic hydrazide approximately six weeks before harvest (left), non-treatcontro!s (right). Top, Pontiac; bottom, Irish Cobbler.

Discussion

Several chemicals (3, 4, 16) have been suggested as effective for t]inhibition of sprouting of potatoes during storage. Applications of sproiinhibitors to growing crops may have distinct advantages. The relati'effectiveness of the chemical may be much greater on growing crops becauof the rapid absorption, penetration, and translocation to the desired plaiorgans, which usually occurs with foliar applications to growing crops:ennfrAtrPdcI wi+ith nn'R.-hn.rvpqd, trPAtrnPntcz whieh mr.v f,iil 1inlIPz zncpisal nr,

138




TABLE IITHE EFFECTS OF A PREHARVEST FOLIAR SPRAY OF MALEIC HYDRA ZIDE ON THE

SUGAR CONTENT OF IRISH COBBLER POTATOES AFTER SEVEN MONTHSSTORAGE AT 45 AND 55°F (EXPRESSED AS PER CENT. OF DRY WEIGHT).

Reducing sugar Non-reducing sugarTreatment

Replication 1 Replication 2 Replication 1 Replication 2

450 F.Maleic hydrazide 1.63 1.65 0.69 0.76Control 3.26 2.68 1.21 1.02

550 F.Maleic hydrazide 0.56 0.42 1.05 0.77Control 0.62 0.52 1.63 1.25

visions facilitating penetration are provided (7, 11). Formulations of alpha-naphthaleneacetic acid and 2,4,5-trichlorophenoxyacetic acid, when sprayedon growing potato plants to reduce or inhibit subsequent sprouting duringstorage have frequently resulted in tuber injuries and in a reduction ofquality (7, 15, 21). In this connection, maleic hydrazide is unique in thatno apparent abnormalities or loss of quality are evident even at concentra-tions which induce permanent dormancy.

A number of interesting aspects are associated with the use of maleichydrazide as a sprout inhibitor. There is a considerable latitude in thetime during the growing season that the chemical can be applied with effec-tiveness and in the concentrations which can be used. It appears that withadjustments of spraying times and concentrations, almost any degree ofinduced dormancy may be possible.

Tubers from treated lots which showed no evidence of sprouting in stor-age were planted into the field in the spring of 1951, but gave no evidenceof growth activity. Similar results have been reported for onions (18). Testsare under way utilizing various means of breaking this induced dormancy.

Prolonging dormancy with maleic hydrazide is also unique in that apicaldominance is apparently destroyed in both the tuber and in the potentialindividual sprouts on the tuber. Unlike the knobby suppressed sproutswhich may eventually develop on the apical ends of tubers following treat-ments with the methyl ester of alpha-naphthaleneacetic acid and 2,4,5-tri-chlorophenoxyacetic acid, maleic hydrazide inhibits completely the apicalregion of the potato and growth, when it occurs, is initiated at the basal end(fig. 2).

Several economic problems exist in the storage of potatoes. At rela-tively low temperatures (32 to 450 F) a degradation of starch occurs andsugars accumulate resulting in a sweetened product of poor quality for de-hydration, chip manufacture, and ordinary table use. Conversely, if rela-tively high (above 40° F) storage temperatures are utilized, losses fromsprouting and shriveling occur along with a rapid deterioration of ediblequality. According to ARREGUIN-LOZANO and BONNER (1), the regulation

139



PLANT PHYSIOLOGY

of starch degradation and sugar synthesis by temperature in potato tubersappears to reside in a powerful phosphorylase enzyme rather than an amy-lase system. At least three reactions are involved in the temperatureeffects: 1. regulation of the amount of phosphorylase enzyme inhibitorwhich is produced at high temperatures, 2. regulation of the activity of theglucose-fructose interconverting system which is increased at low tempera-tures, and 3. regulation of the activity of the sucrose synthesizing enzymewhich is increased in amount at low temperature storage.

Maleic hydrazide as an agent for prolonging dormancy in the storage ofpotatoes has permitted the use of temperatures up to 550 F without thehazard of sprouting, and analyses of treated tubers after seven months stor-

:

.. . : : ~~~~~~~~~~~~.

-9.i>..........aX :m

.......................

FIG. 2. The apical (left) and basal (right) ends of Pontiac tubers showing the rela-tively greater inhibition of growth on the apical end indiled by maleic hydrazide.

age at 450 F showed the presence of only half the quantities of reducing andnon-reducing sugars in non-treated lots. According to DENNY and THORN-TON (5) reducing sugars which may accumulate at low temperatures, andnot sucrose, are responsible for poor quality (dark color) in pot-ato chips.In the present study, potato chips were processed from maleic hydrazidetreated and non-treated Irish Cobbler and Pontiac tubers held for sevenmonths at 45 and 550 F. The color quality of chips from treated tuberswas judged superior in each instance.

While the effects of 2,4 5-trichlorophenoxyacetic acid and the methylester of alpha-naphthaleneacetic acid on the respiratory activity of producetreated for spiout inhibition have not been fully clarified (6, 8), there hasbeen assembled considerable evidence, aside from data herein reported, that

140




maleic hydrazide is a selective respiratory inhibitor (9, 12, 17). In thepractical storage of produce, accumulated results (18, 19, 20) suggest a use-ful application of the response induced in some plants by this uniquegrowth-regulator.

SummarySprays of 500, 1000, and 2500 p.p.m. of maleic hydrazide applied to the

foliage of Irish Cobbler and Pontiac potato vines approximately one toseven weeks prior to harvest were effective in prolonging dormancy oftubers held in storage for seven months at temperatures of 45 and 550 F.

The inhibition of sprouting resulting from single preharvest foliar spraysof 2500 p.p.m. of maleic hydrazide applied four to seven weeks before har-vest was more complete than that obtained with preharvest foliar treat-ments of 2,4,5-trichlorophenoxyacetic acid or with post-harvest applicationsof the methyl ester of alpha-naphthaleneacetic acid.

Maleic hydrazide-induced sprout inhibition treatments were accompaniedby an absence of shriveling with little or no deterioration of quality andwith no reduction of yield of U. S. no. 1 potatoes. Apical dominance of bothtubers and individual sprouts on the tubers was destroyed. The percentagesof reducing and non-reducing sugars were lower in maleic hydrazide treatedpotatoes stored at 450 F. The lower content of reducing sugar was evi-denced in lighter colored chips.

The possible significance of maleic hydrazide in controlling the degra-dation of starch to sugar in the storage of potatoes at low temperatures aswell as the inhibition of sprouting at high temperatures is discussed.

DEPARTMENTS OF HORTICULTURE AND AGRICULTURAL CHEMISTRYMICHIGAN STATE COLLEGE

EAST LANSING, MICHIGAN

LITERATURE CITED1. ARREGUIN-LOZANO, B. and BONNER, J. Experiments on sucrose forma-

tion by potato tubers as influenced by temperature. Plant Physiol.24: 720-738. 1949.

2. ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS. Official and Tenta-tive Methods of Analysis. Sixth Edition. 144. 1945.

3. BROWN, W. Experiments on the effect of chlorinated nitrobenzenes on.the sprouting of potato tubers. Ann. Ap. Biol. 34: 422-429. 1947..

4. DENNY, F. E. Further tests on the use of the methyl ester of alpha--naphthaleneacetic acid for inhibiting the sprouting of potato tubers..Contrib. Boyce Thompson Inst. 11: 15-20. 1945.

5. DENNY, F. E. and THORNTON, N. C. Factors for color in the produc-tion of potato chips. Contrib. Boyce Thompson Inst. 11: 291-303.1940.

6. ELLISON, J. H. and SMITH, ORA. Effects of spraying a sprout inhibitoron potato plants in the field. Proc. Amer. Soc. Hort. Sci. 51: 397-400. 1948.

141



PLANT PHYSIOLOGY

7. ELLISON, J. H. and SMITH, ORA. Retarding sprout growth of potatotubers by spraying the foliage with 2,4,5-trichlorophenoxyaceticacid. Proc. Amer. Soc. Hort. Sci. 54: 447-451. 1949.

8. GANDARILLAS, H. and NYLUND, R. E. Further studies on the influenceof sprout-inhibiting and sprout-inducing treatments on the growthand yield of potatoes. Amer. Potato Jour. 26: 7-16. 1949.

9. ISENBERG, F. M. R., ODLAND, A{. L., Popp, H. WV., and JENSEN, C. 0.The effect of maleic hydrazide on certain dehydrogenases in tissuesof onion plants. Science 113: 5940. 1951.

10. MARSHALL, E. R. and SMITH, ORA. Effect of field and storage applica-tions of sprout inhibitors on potato tubers. Amer. Potato Jour. 27:133-141. 1950.

11. MARSHALL, E. R. and SMITH, ORA. Maleic hydrazide as a sprout inhib-itor for potatoes. Bot. Gaz. 112: 329-330. 1951.

12. NAYLOR, A. W. and DAVIs, E. A. Respiratory response of root tips tomaleic hydrazide. Bull. Torrey Bot. Club 78: 73-79. 1951.

13. SCHOENE, D. L. and HOFFMAN, 0. L. Maleic hydrazide, a uniquegrowth regulant. Science 109: 588-590. 1949.

14. SELL, H. M., JOHNSON, F. A., and LOGASSE, F. S. Changes in the chem-ical composition of the tung fruit and its component parts. Jour.Agr. Res. 73: 319-334. 1946.

15. SMITH, ORA, BAEZA, M. A., and ELLISON, J. H. Response of potatoplants to spray applications of certain growth-regulating sub-stances. Bot. Gaz. 108:421-431. 1947.

16. SMITH, ORA, ELLISON, J. H., and McGOLDRICK, F. Growth of potatosprouts retarded by 2,4,5-trichlorophenoxyacetic acid. Science109: 66-68. 1949.

17. SMOCK, R. M., EDGERTON, L. J., and HOFFMAN, M. B. Some effects ofmaleic hydrazide on the softening and respiration of apple fruits.Proc. Amer. Soc. Hort. Sci. (In press).

18. WITTWER, S. H. and SHARMA, R. C. The control of storage sprouting inonions by preharvest foliage sprays of maleic hydrazide. Science112: 597-598. 1950.

19. WITTWER, S. H., SHARMA, R. C., WELLER, L. E., and SELL, H. M. Theeffect of preharvest foliage sprays of certain growth regulators onsprout inhibition and storage quality of carrots and onions. PlantPhysiol. 25: 539-549. 1950.

20. WITTWER, S. H. and HANSEN, C. M. The reduction of storage losses insugar beets by preharvest foliage sprays of maleic hydrazide. Ag-ronomy Jour. 43: 340-341. 1951.

21. WOOD, D. C. and ENNIS, W. B. Influence of butyl 2,4,5-trichlorophe-noxyacetate upon the development of tuber abnormalities in Irishpotatoes. Agronomy Jour. 41: 304-308. 1949.

142



ERRATAVolume 26:

Page 521, line 3, liberation of organic phosphate should read liberation of inorganicphosphate.

Page 598, line 29, component may be expressed should read component (solvent orconstituent solute) may be expressed.

Page 598, line 30, molal free energy difference per liter of component flux shouldread molal free energy difference divided by the partial molal volume (at itsreference state) of the constituent component subject to flux consideration.

Page 599, lines 23 and 24, V2 in liters should read V2 in liters per mole.Page 599, lines 27 and 28, V2 is the partial molal volume of the constituent solute

in solution, in liters should read V20 is the partial molal volume of the constitu-ent solute in solution, in liters per mole.

Pages 599 to 608, factor v should read V°.Page 600, line 9, delete of solute flux.

Page 60, line 16, equation (27) should read REE= m m t .Page 603, line 18, The ratio V/m should read The factor Ax V0/m.Page 603, line 19, delete of solute flux.Page 603, line 20, RNI is in grams should read RNI is in grams per square centi-

meter per second.Pages 655 to 672, factor V should read V°.Page 657, line 45, delete In other words, flux intensities are not forces per unit area,

but rather are forces concerned with the ordered movement of a unit volumeof a constituent component of solution through a unit of distance.

Pages 699, 701, 703, 705, and 707, title, Acetaldehyde should read Aldehydes.Page 787, line 37, in the 5/P and 2/P groups should read in the 5P and 2P groups.

Volume 27:Page 104, lines 38 and 42, and Page 105, lines 3 and 4, Method 1 should read

Method a and Method 2 should read Method b to correspond with designationsin figure 3.

Page 109, line 12, affect should read effect.Page 140, paragraph 2, line 5, non-reducing sugars in non-treated lots should read

non-reducing sugars as was in non-treated lots.Page 463, line 23, K, the constant, should read K, the constants.Page 463, line 25, V' should read V'.Page 466, legend for figure 5, interference of Na and Rb uptake should read inter-

ference of Na with Rb uptake.Page 469, Table I, Figure 5 should read Figure 3.Page 469, Table I, Figure 6 (left) should read Figure 4 (left).Page 469, Table I, Figure 11 should read Figure 8.Page 470, line 10, which the un-competitively affected should read which are un-

competitively affected.Page 471, Table II, Figure 6 (right) should read Figure 4 (right).Page 471, Table II, Figure 7 should read Figure 5.Page 530, line 5, although specifically should read although not specifically.Page 530, line 15, adenosine triphosphate should read adenosinephosphatase.

Documents

I, 0.1% · receiving 2500 p.p.m. of maleic hydrazide on either July 15 or August 2 were clean, bright, firm, and practically free from any evidence of sprout growth, even after seven