THE INHIBITION OF SEEDLING GROWTH BY CROP ...

University of Nebraska - Lincoln

DigitalCommons@University of Nebraska - Lincoln Publications from USDA-ARS / UNL Faculty

USDA Agricultural Research Service --Lincoln, Nebraska

4-1-1963

THE INHIBITION OF SEEDLING GROWTH BY CROP RESIDUES IN SOIL INOCULATED WlTH PENICILLIUM URTICAE BAINER D. E. Behmer T. M. McCalla

Follow this and additional works at: http://digitalcommons.unl.edu/usdaarsfacpub Part of the Agricultural Science Commons Behmer, D. E. and McCalla, T. M., "THE INHIBITION OF SEEDLING GROWTH BY CROP RESIDUES IN SOIL INOCULATED WlTH PENICILLIUM URTICAE BAINER" (1963). Publications from USDA-ARS / UNL Faculty. Paper 159. http://digitalcommons.unl.edu/usdaarsfacpub/159

This Article is brought to you for free and open access by the USDA Agricultural Research Service --Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications from USDA-ARS / UNL Faculty by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln.

Plant and Soil XVIII, no. 2

April 1963

THE INHIBITION OF SEEDLING GROWTH BY CROP RESIDUES IN SOIL INOCULATED WlTH PENICILLIUM URTICAE BAINER * by D. E. B E H M E R and T. M. McCALLA ** INTRODUCTION

In the Great Plains area of the United States, stubble-mulch practices have been widely used in the control of soil erosion by wind or water. Although this method of leaving crop residue on the surface has been very effective in combating erosion, depressed plant growth and reduced grain yield have often occurred in wer years. Similar growth problems have been observed during unseasonably cool, wet springs in field experiments at Lincoln, Nebraska. Because increased numbers of certain micro-organisms occur immediately beneath a decomposing surIace mulch, the production of phytotoxic compounds under these conditions m a y well have been associated with the adverse effect on plant growth. In fact, a strain of Peuicil~ium urlicae Bainer isolated from stubble-mulch plots at Alliance, Nebraska, has been {ound to produce a phytotoxic substance when grown in culture media ( N o r s t a d t and M c C a l l a 6). Effects of mierobial decomposition of plant residues on seedling growth have been studied by numerous investigators.Pat r i c k 7show_ ed that fumigation of a peach-orchard soil prevented the development

* Joint contribution from University of Nebraska and Saii and Water Conservation Research Division, Agri•ultural Research Service, U.S. Department of Agrigulture , and Nebraska Agricultural Experiment Station, Lincoln, Nebraska, cooperating. Published with the approval of the DJrector as Paper No. 1242, JournaI Series, Nebraska Agricultural Experiment Station. ** Graduate student, University of Nebraska, and Research Microbiologist, USDA, Lincoln, Nebraska, respectively.

--

199

--

200

D.E. BEHMER AND T. M. MCCALLA

of a s u b s t a n c e toxic to p e a c h tree seedlings. S w a b y s tested p l a n t response to incorporations of organic m a t t e r in sterile a n d inocul a t e d sand. H e concluded t h a t the addition of organic m a t t e r u n d e r sterile conditions does not iniluence growth, b u t t h a t the microbial decomposition of organic m a t t e r m a y produce p l a n t - g r o w t h - i n h i b i t o r y substances. Culture filtrates of Aspergillus ~¢iger will induce severe e u r v a t u r e of corn-seedling roots ( C u r t i s 2). T h e g r o w t h s u b s t a n c e in the culture filtrate has been isolated a n d identified as a n e u t r a l cyclic peptide c o m p o u n d t h a t has been given the n a m e mal/ormi•. A filt r a t e t h a t induced curling of roots a n d caused reduced root a n d shoot g r o w t h of w h e a t seedlings was p r o d u c e d b y a culture of P. ~~rticae ( N o r s t a d t and M c C a l l a 6). One of the toxic substances f r o m the culture filtrate was identified as Patulin. Several workers h a v e shown t h a t erop residue e x t r a c t s depress p l a n t g r o w t h (Coll i s o n a n d C o n n 1, N e w t o n a n d Y o u n ä 4, N i e l s e n , C u d d y , a n d " W o o d s õ). Aqueous e x t r a c t s of sorghum, corn, oats, sweetclover, wheat, s o y b e a n , a n d b r o m e - g r a s s residues were toxic to corn, wheat, a n d s o r g h n m seedlin~s ( G u e n z i a n d M e C a l l a s). T h e p u r p o s e of this s t u d y was to d e t e r m i n e if wheat-seedling growth inhibitors are present in crop residues in the soil, a n d if P. urticae produces substances toxic to w h e a t seedlings in residuet r e a t e d soll.

MATERIALS AND METHODS Samples of the plow layer of a Sharpsburg silty clay loam s0il were taken from the Agronomy I~arm, Lincoln, Nebraska, oll an east slope of 4 per cent. The dark-colored, friable surface layer of 8 to 12 illches covers a finer textured zone which grades into a light-brown parent material of Peorian loess origin. The soil samples were composited, air dried, and passed through a 2 mm sieve. The bulk soll was divided into fonr parts, three of whieh were separately mixed with 1% by weight of fillely ground (to pass 40-mesh screen) aKalfa, corll and sorghum stover residlle. ~No residue was added to the fourth part. From each of the four parts of soil or soil with residue, eighteen 50-g samples were weighed into individual 100-mm petri dishes, and the dishes and contents were autoclaved for 2 hours. Nine dishes of eaeh type were then inoculated with a suspension of P. urticae spores in modified Crone's solution (7.1 g NH4NOa and 3.6 g IK2HPO4 per liter of distilled watet). Spores for inoculatioll were harvested from 8-week-old rose-bengal slallt cultures. The

EFFECT OF CROP RESIDUES ON SEEDLING GROWTH

201

c o u n t of viable spores in the inoculating suspension was a p p r o x i m a t e l y i5,000 per ml. A sufficient v o l u m e of suspension was used to bring the moisture c o n t e n t of the soil to 40% (I moisture e q u i v a l e n t equals 27% moisture). To the remaining nine petri dishes of each type, sterile Crone's solution was added in sufficient q u a n t i t y to bring the moisture level oi the soil to 40%. The e x p e r i m e n t thus included 8 t r e a t m e n t combinations of residue and inoculum, w i t h each t r e a t m e n t represented b y 9 petri dishes.

Fig. 1. H u m i d i t y chambers used in the experiment. C o m p o n e n t parts are: 1 1arge petri plate, 2 iarge r u b b e r stoppers, and a I-liter beaker. All 72 petri dishes were incubated at 24°C in a m o i s t u r e - s a t u r a t e d atmosphere. A f t e r 2 weeks of incubation, 3 dishes of each t r e a t m e n t were p l a n t e d w i t h 15 fungicide-treated * Cheyenne w i n t e r - w h e a t seeds. W h e a t seeds were p l a n t e d in a second 3 dishes of each t r e a t m e n t after 3 weeks of incubation, and in the final 3 dishes after 4 weeks of incubation. P l a n t e d plates, w i t h o u t lids, were placed in hulllidity chambers, as shown in Figure 1. D a t a on seed germination and on length and weight (oven-dry basis) of the seedlings were recorded after 7 days of growth at 24°C.

* Orthocide - active ingredient, N-trichloromethylmercapto-4-cyclohexene-l,2-dicarboximide.

202

I). E . B E H M E R

EXPERIMENTAL

A N D T. M. M C C A L L A

RESULTS AND DISCUSSION

The influence of crop residues, P. urticae inoculation, and different incubation periods (prior to planting) on the germination and growth of wheat seedlings in soll is shown in Table 1, and an analysis of variance is shown in Table 2. TABLE

1

W e i g h t * ( o v e n - d r y basis) a n d I e n g t h * of w h e a t shoots, a f t e r 7 d a y s of g r o w t h , a n d g e r m i n a t i o n p e r c e n t a g e * of w h e a t in P. urticae-inoculated a n d non-inocul a t e d soil c o n t a i n i n g 1% b y w e i g h t oi finely g r o u n d alfalfa, corn, a n d s o r g h u m residues. Soil i n c u b a t i o n period ** 2weeks

Residue t r e a t m e n t

3 weeks

4weeks NoILinoc.

Noninoc.

Inoc.

No~inoc.

Inoc.

99 104 94

110 102 101 91 101

107 104 96 80 97

93

86 96

103 98 93 86 95

132 1!7 lll 93 113

133 99 89 76 99

128 118 I00 88 108

125 101 86 62 94

93 89 100

100 t00 100 I00 100

98 93 98

t00 100 I00 I00 100

Mean

Inoc.

Weight o/wheat shoots (mg) None . . Corn . . Sorghum Alfalfa . Mean .

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

. . . . .

. . . . .

. . . . .

. . . . .

. . . . .

. . . . .

96 98 86 62 86

101 99 94

114 100 103 67 96

127

126 106 97 74

I00 98 I00 98 99

98

86 93

70 86

79

Length of wheat shoots (mm) None . . Corn . . Sorghum Alfalfa . Mean

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

. . . .

. . . .

. . . .

. . . .

. . . .

. . . .

. . . . . . . . . .

103 91 58 95

Germi~.atio~~ (%) None . . . . . . . . . . . Corn . . . . . . . . . . . Sorghum

. . . . . . . . .

Alfalfa

. . . . . . . . . .

98

Mean

. . . . . . . . . .

95

98

97

80 98 89

98 93 99 97

91

* Mean of t h r e e replications w i t h a t o t a l of 45 seeds. ** T i m e elapsed f r o m w e t t i n g to p l a n u n g , i n c u b a t i o n at 24°C.

Addition of corn and sorghum stover and alfalfa hay residues to the soff effectively reduced yields as compared to the soil without residues. Alfalfa residues reduced both length and weight of shoots to the greatest extent. Seedling shoot-length was reduced in all cases by addition of

EFFECT

OF CROP RESIDUES

TABLE

ON SEEDLING

GROWTH

203

2

A n a l y s i s of v a r i a n t e of l e n g t h a n d w e i g h t ( o v e n - d r y basis) of w h e a t s h o o t s , a f t e r 7 d a y s of g r o w t h , a n d g e r m i n a t i o n p e r c e n t a g e of w h e a t in P. urticae-inoculated a n d n o n - i n o c u l a t e d soil c o n t a i n i n g 1% b y w e i g h t of f i n e l y g r o u n d a l f a l f a , c o r n , a n d s o r g h u m residues. Degrees S o u r c e of v a r i a t i o n

Reßidues . . . . . . . . . . Incubation periods . . . . . Residues × incubation periods Inoculation . . . . . . . . Inoculation × residues . . . Inoculation × mcubation periods . . . . . . . . . Inoculation × residues × incubation periods .... Error . . . . . . . . . . .

of freedom

6 48

.

Mean square Wheat shoots Length

Weight

Germination

8,561.8'* 710.3"* 132.9 1,859.5'* 398.9**

1,627.8"* 1,702.8** 112.4 6.3 82.3

1.22 2.39 1.22 0.50 0.76

351.3"*

174.4

4.50*

40.0 74.2

36.8 98.6

0.93 1.29

* S i g n i f i c a n t a t t h e 5 % level ** S i g n i f i c a n t a t t h e 1 oB levei

residue to the soil. Furthermore, m most cases inoculation with P. urticae caused an additional stunting of the shoots (Fig. 2). Increasing the length of the incubation period prior to planting caused a slight reduction in seedling weight and length on the control soll and the corn and sorghum-treated solls. Soll treated with alfalIa residues became progressively more toxic to wheat-seedling growth with length of incubation. The high toxicity of incorporated alfalfa residue suggests the presence of natural plant-growth inhibitors. However, inoculation of the alIalfa residue with P. urticae increased this toxic effect, especially with increased incubation time prior to planting. Wheat seedlings grown in soll treated with alfalfa residue, inoculated with P. urticae, and incubated for 3 and 4 weeks prior to planting, developed a root curling not evident with other residue treatments (Fig. 3). There was also some indication of root curling at the 2-week incubation period. Although differences were not statistically slgnificant, germination of wheat appeared to be quantitatively improved in soil inoculated with P. urticae, except at the 4-week incubation period. The interaction between inoculation and incubation period was shown to be significant at the 5% level of probability.

204

D. E. BEHMER

AND

T. M. MCCALLA

Fig. 2. Appearance of 7-day-old wheat seedlings growing on Sharpsburg silty clay loam soll incubated 3 weeks prior to planting. U pper, containing 1% incorporated alfalfa residue- leit, non-inoculated; right, P. urticae inoculated. Lower, containing (leit) no residue; and (right) 1% alfalIa residue. Both plates received P. urticae inoculation. A n y effects of adverse C/N ratio caused b y the addition of residue to this soll should h a v e been offset b y the nitrogen present in the wetting solution (Crone's medium). Autoclaved P . urticae


20,5

Fig. 3. Root patterns of 7-day-old wheat seedlings growmg in moist Sharpsburg silty clay loam soll. Soil was incubated for 4 weeks prior to planting of the wheat.

upper, containing no residue; Iower, leit, 1% incorporation of alIalfa residue, non-inoculated; lower right, 1% incorporation of alfalfa residue, P. urticae-inocutated.

might have been added to the non-inoculated soil as a proof that growth eIfects were attributable to the viable mold. However, at this very low concentration it is doubtIul that there was any efIect, since the inoculated control soil outyielded the non-inoculated control soil throughout the experiment. Although residues alone eIfected a reduction in seedling growth, P. urticae caused reduced growth only in the presence of residues. These findings suggest that crop residues in soils, alone or in combination with P. urticae, may cause depressive efIects on the growth of wheat seedlings. The presence of certain soil-inhabiting fungi

206


and their action in plants

of c r o p r e s i d u e s . onstrated

on crop residues

whose root systems However,

may

induce

are exposed

growth

retardation

to degradation

these relationships

products

have not been dem-

in the field. SUMMARY

L a b o r a t o r y e x p e r i m e n t s were c o n d u c t e d to d e t e r m i n e t h e effects of crop residues, w i t h o u t a n d w i t h Penicillium urticae B a i n e r i n o c u l a t i o n , o n g r o w t h of w h e a t seedlings in soil. F i f t y g r a m s of S h a r p s b u r g silty clay l o a m soil, c o n t a i n i n g 1 °/o b y w e i g h t of i n c o r p o r a t e d alfalfa, s o r g h u m a n d c o r n s t o v e r residue, were p l a c e d in p e t r i dishes, a u t o c l a v e d , w e t t e d to 4 0 % m o i s t u r e , a n d i n c u b a t e d a t 24°C. for periods of 2, 3, a n d 4 weeks. O n e - h a l f of t h e p e t r i dishes were i n o c u l a t e d w i t h P. urticae. G e r m i n a t i o n a n d s e e d l i n g - s h o o t m e a s u r e m e n t s were t a k e n a f t e r 7 d a y s of growth. T h e results of t h i s s t u d y s h o w e d t h a t (1) i n o c u l a t i o n of soil g e n e r a l l y r e d u c e d seedling h e i g h t regardless of t h e residue t r e a t m e n t ; (2) i n o c u l a t i o n of soil c o n t a i n i n g c o r n a n d s o r g h u m residues r e s u l t e d i n g r e a t e r tissue prod u c t i o n b u t r e d u c e d h e i g h t of seedlings as c o m p a r e d to n o n - i n o c u l a t e d soils; a n d (3) in t h e a b s e n c e of residues, t h e i n o c u l a t e d c o n t r o t soils were a b e t t e r g r o w t h m e d i u m for w h e a t seedlings t h a n were t h e n o n - i n o c u l a t e d c o n t r o l solls. I n a d d i t i o n , Mfalfa residues, especially in t h e p r e s e n c e of P . urticae, were s t r o n g l y i n h i b i t o r y to t h e w h e a t seedlings, c a u s i n g curling a n d r e d u c e d w h e a t - s e e d l i n g r o o t growth. Received June 5, 1962 REFERENCES 1 Collison, R. C. and Conn, H. J., The effect of straw on plant growth. New York (Geneva) Agr. Expt. Sta. Tech: Bull. 114 (1925). 2 Curtis, R. W., Studies on response of bean seedlings and corn roots to malformin. Plant Physiol. ;16, 37-43 (1961). 3 Guenzi, W. D. and MeCalla, T. M., Inhibition of germination and seedling development by crop residues. Soll Sci. Soe. Am. Proe. 26, 456-458 (1962). 4 N e w t o n , R. and Young, R. S., Nitrification under and after alfalfa, brome, timothy and western rye grass. V. Biological assays of ha}, crop residues. Can. J. Research 18, 374-387 {1940). 5 Nielsen, K. F., Cuddy, T. F. and Woods, W. B., The influence of the extract of some crops and soil residues on germination and growth. Can. J. Plant Sci. 40, 188-197

(1960). 6 N o r s t a d t , F. A. and MeCalla, T. M., A phytotoxic substance from a speeies of Penicillium. Seience (submitted) (1963). 7 P a t r i c k , Z. A., The peaeh replant problem in Ontario. II. Toxie substances from microbial decompoSition products of peach root residues. Can. J. Botany 33, 461-468 (195s). 8 Swaby, R. J., Stimulation of plant growthby organic matter. J. Australian Inst. Agr. Sci. 8, 156-163 {1942).