Salinity and It's Effect on the Germination Rates of Radishes- Ranier Knowles

8/20/2019 Salinity and It's Effect on the Germination Rates of Radishes- Ranier Knowles

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THE EFFECT OF SALINITYON THE GERMINATION

RATE OF RADISHES

The effects of salt and osmotic stresses on the germination processesin seeds of the species Raphanus sativus (common radish) were

compared using various concentrations of saline solutions. The loweststress intensity delayed germination, while higher doses of NaCl

reduced final germination percentages. While the germination rate ofseeds used as a control group was noticeably more successful, No

significant difference occurred between the effects of these solutes ongermination percentages in concentrations of saline solutions with a

sodium chloride percentage of less than !. "nhibited seeds sub#ect tosaline solutions with a percentage of sodium chloride higher than !

showed stunted or no signs of physical development after theduration of the e$periment %eed germination in water and underwater stress (NaCl) was evaluated within a lab environment.

Ranier &nowles


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THE EFFECT OF SALINITY ON THE GERMINATIONRATE OF RADISHES - Ranier Knowles

INTRODUCTION'ermination is a vital stage of development for spermatophytes. The individualsurvival of a plant is dependent on weather or not a seed germinates effectively.The survival of a species is therefore dependent on the ability for a seed toaffectively reproduce and germinate effectively. The conditions under whichgermination can occur are vital. ature seeds of some species are incapable ofgerminating, even under ideal conditions of temperature and hydration. %uchseeds are nown as *dormant+. ormancy must be bro en in order for a seed toeffectively germinate. ormancy of these seeds is bro en individually dependingon the type or species of seed- though all dormancy can be bro en throughvarious combinations of light intensity, temperature fluctuation, acidity, ore$ternal scarification.

nce dormancy is bro en given the right circumstances (temperature, lighting,moisture, o$ygen,) seeds will naturally absorb water through osmosis. /n0ymeswithin the plant and food supplies become *hydrated+. 1ydrated en0ymesbecome active and the seed increase its metabolic activities to produce energyfor the growth process. "n addition, the absorption of water causes turgorpressure to increase in the cells and they are able to enlarge through a process

nown as imbibition. This reaction

The primary effect of salts on germination is osmotic. Water upta e by seeds isdecreased by elevated salinity levels, thus or halting germination.. 2ccordingly,imbibition, similar to osmosis, involves the movement of water down a potentialgradient. Thus, the water potential within a substrate must be greater than thewater potential in the cells of the seed, in order for water to move from thesubstrate into the cells of the seed. %alinity effects germination by reducing thesubstrates water potential, thereby restricting water and nutrient upta e to theseeds. (National 3ibrary of edicine, 445) %alt stress mimics water stress inmany ways leading to the suggestion that the principal effect of salt is osmotic.

delayed germination, high rate of seedling mortality, stunted growth andreduced yield are some of the most common effects of salted soils. 1oweversince some salts are more inhibitory than others, specific to$ic effects must alsobe involved. 2lthough sodium chloride (table salt) is among the less to$ic salts, itis one of the most common and thus one of the most troublesome to agriculturehence its inclusion in this e$periment. The purpose of this e$periment is todemonstrate the effect of numerous solutions of sodium chloride on commonradish seeds and compare their rates of germination to determine the effect ofsalinity on the germination rate of a shallow rooted crop.

HYPOTHESIS


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The germination rate of radishes will decrease as the concentration of the salinesolution increases- this is because salt will decrease or halt the seeds ability toimbibe water.MEATHODS1ow does salinity affect the germination rate of seeds of the species Raphanussativus (common radish). "f the concentration of salinity increases within asubstrate, the germination rate of the seeds will decrease uniformly. Throughoutthe e$periment, the rate of germination of the species Raphanus sativus (common radish) was tested by sub#ecting 4 seeds to 6 different concentrationsof a saline solutions increasing in increments of 4.7!. The e$periment wasconducted using 6 petri dishes based with a substrate consisting of paper towel.8ml of each saline solution were absorbed within the substrate of each petri dish.The results of this e$periment were compiled over the course of a wee . Thegermination rate of seeds of the species Raphanus sativus (common radish)were observed to slow or decrease before plummeting after a concentration of

! halting germination completely. The results of this e$periment partiallysupported the hypothesis the effect of salinity could be summed up through thedelay of seed germination, and the decline in its rate and percentage.

MEATHODOLOGY

-9 petri dishes

-Paper towe

-Ta! e sa t "NaC #

-Meas$ri%& '$p

- Se%siti(e )eas$ri%& s'a e 'apa! e o* )eas$ri%& s)a a)o$%ts+

-Disti ed water

- , . radish seeds

-Shoe!o/0!o/ ar&e e%o$&h to )ai%tai% a sa)p es+

-9 ar&e * as1s0!ott es "'apa! e to ho d , itre o* water#

- Ni1o0 ! a'1 per)a%e%t )ar1er

MEATHOD2

- Meas$re di**ere%t a)o$%ts o* ta! e sa t with s'a e i%'reasi%& *ro) 3&ra)s to 4.&ra)s i% 3-&ra) i%'re)e%ts+

- Meas$re , itre o* disti ed water a%d po$r i%to ea'h o* the 9 * as1s+- Add sa t to respe'ti(e * as1s a!e i%& d$ri%& this pro'ess- Re)o(e 5 ea* ets o* paper towe a%d *o d i% ha *

- S1et'h Petri dish o%to paper towe s- C$t o$t petri dish )o$ d *ro) paper towe


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- P a'e , petri dish shaped pie'e o* paper towe i% ea'h petri dish- Add 6. seeds to ea'h petri dish- Meas$re 4 ) o* ea'h sa t so $tio% a%d p a'e respe'ti(e 7 i%to ea'h o* the petri

dishes ea(i%& , petri dish with p$re disti ed water as a 'o%tro +- P a'e ids o% petri dishes- 8se tape to sea the petri dishes- P a'e a petri dishes i%to !o/- P a'e !o/ i% war) dar1 p a'e that does% t * $'t$ate dra)ati'a 7 i% te)perat$re- Che'1 e(er7 da7 a%d re'ord res$ ts re ati%& to the rate o* &er)i%atio% 'o)pared to

the sa t 'o%'e%tratio%+

RESULTS

GERMINATION RATE OF RADISHES GERMINATED :ITHIN ;ARIO8S SALINE SOL8TIONS

NaCL < N8M=ER OF SEEDS GERMINATEDDa7 . Da7 , Da7 6 Da7 5 Da7 4 Da7 3 Da7 >

Co%tro". ,9 6. 6. 6. 6.,+3< . ,, ,> , 6. 6. 6.6< . 4 ,5 ,3 ,9 6. 6.

6+3< . 6 ? ,6 ,5 ,> ,>5< . . . , , , ,

5+3< . . . . . . .4< . . . . . . .

PERCENTAGE GERMINATION RATE OF RADISHES GERMINATED :ITHIN ;ARIO8S SALINESOL8TIONS

NaCL < PERCENTAGE OF SEEDS GERMINATEDDa7 . Da7 , Da7 6 Da7 5 Da7 4 Da7 3 Da7 >

Co%tro".3 ?3 93 ,.. ,..

6+3< . ,. 53 >. >3 . .5< . . . 3 3 3 3

5+3< . . . . . . .4< . . . . . . .


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DISSCUSSIONThe owest sa i%e i%te%sit7 de a7ed &er)i%atio%@ whi e hi&her per'e%ta&es o* sa t "NaC #withi% the sa i%e so $tio% red$'ed *i%a &er)i%atio% per'e%ta&es+ :hi e the &er)i%atio% rateo* seeds $sed as a 'o%tro &ro$p was %oti'ea! 7 )ore s$''ess*$ @ No si&%i*i'a%t di**ere%'eo''$rred !etwee% the e**e'ts o* these so $tes o% &er)i%atio% per'e%ta&es i% 'o%'e%tratio%s

o* sa i%e so $tio%s with a sodi$) 'h oride per'e%ta&e o* ess tha% 6.

-.

,..

,6.

. , 6 5 4 3 > ?

P E R C E N T A G E G E R M I N A T I O N R A T E

DAYS

PERCENTAGE GERMINATION RATE OF RADISH SEEDS

GERMINATED :ITHIN ;ARIO8S SALINE SOL8TIONS

CONTROL .< NaC .+3< NaC ,< NaC

,+3< NaC 6< NaC 6+3< NaC

5< NaC 5+3< NaC 4< NaC


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o* sa t a ows it to !e hi&h 7 h7dros'opi' a!sor!i%& waster easi 7+ This res$ ts i% the e**e'tsdisp a7ed thro$&ho$t this e/peri)e%t+

The desi&% o* the e/peri)e%t a%d the a''$ra'7 o* the data 'o e'ted was )oderate+ Tho$&hthe data was 'o e'ted withi% a a!orator7 e%(iro%)e%tB the data )a7 !e !iased !ased $po%

e/ter%a *a'tors+The da7ti)e a%d %i&htti)e te)perat$re was e*t to * $'t$ateB this 'o$ d ha(e !iased e**e'tsre ati%& to the &er)i%atio% ti)e o* the seeds !ased towards the te)perat$re o* the roo)o% a%7 parti'$ ar da7+

Atte)pts were )ade to e%s$re that the a)o$%t o* water &i(e% a%d the a)o$%t o* sa t'o)posi%& the sa i%e so $tio% were a''$rate+ So $tio%s were )i/ed i% ar&er !at'hes toe%s$re that there was a s)a er de&ree o* per'e%ta&e error !ased $po% h$)a% error "+e+&+%ot )eas$ri%& a''$rate 7#+

The ti)es the res$ ts were 'o ated a%d the &er)i%atio% res$ ti%& were o!ser(ed@ (aried da7!7 da7+ This 'o$ d ha(e !iased res$ ts towards da7s were !io o&7 was i% the a*ter%oo%rather tha% the )or%i%&+ Res$ ti%& i% * awed res$ ts !ased $po% the ti)e ta1e% *or seeds to'o%' $de &er)i%atio%+

The a''$ra'7 o* the e/peri)e%t a%d there*ore the data 'o e'ted 'o$ d !e i)pro(ed !7e%s$ri%& that o% 7 o%e depe%de%t (aria! e was !ei%& )eas$red+ Ass$ri%& o% 7 o%ei%depe%de%t (aria! e was

Creati%& a% arti*i'ia e%(iro%)e%t wo$ d a ow the sta!i i atio% o* te)perat$re+ This wo$ de%s$re that the i&ht a(ai a! e to the seeds was 'o%sta%t a%d (ar7i%& e $a 7 !etwee% %i&ht

periods 'o%siste%t with the %at$ra wor d+ The a''$ra'7 o* )eas$re)e%t 'o$ d !e'o)p eted *or !oth sa t water a%d s$!strate )ateria 'o$ d !e 'o)p eted with essper'e%ta&e error+ The te)perat$re 'o$ d ha(e !ee% )o%itored to e%s$re the te)perat$rewas opti)a *or the &er)i%atio% o* the radish seeds@ this wo$ d e%s$re that the o% 7 *a'tor'o%tri!$ti%& to the &er)i%atio% rate was sa i%it7+

%tudies demonstrating the environmental stresses crops are sub#ected to atdifferent stages of development are very important to ensure that we reap thebenefits of an efficient horticulture. %alt, mainly sodium chloride, occursnaturally at high levels in the subsoils of most 2ustralian agricultural land ( 448

avid 9. :annell). 2lthough sodium chloride (table salt) is among the less to$icsalts, it is one of the most common and thus one of the most troublesome toagriculture hence its inclusion in this e$periment. %alinity effects germination byreducing the substrates water potential, thereby restricting water and nutrientupta e to the seeds. (National 3ibrary of edicine, 445) %alt stress mimicswater stress in many ways leading to the suggestion that the principal effect ofsalt is osmotic. The principal effects of salinity on seed germination could besummari0ed in the delay of seed germination, and the decline in its rate andpercentage.

CONCLUSION

2ustralia and its agricultural regions are at particular threat concerning salinityand its underlying causes. ore than 5;444 farms and


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the National 2ction :lan for %alinity and Water =uality (N2: regions), accountedfor showing signs of salinity. >arms primarily involved with the production ofbeef cattle, sheep and grains accounted for 5?,444 or < ! of the farms showingsigns of salinity. &nowing how salinity affects the germination rate of radishes isnot e$actly helpful to the overall health of the 2ustralian agricultural industry.1owever, the implications salinity has on the 2ustralian agricultural industry areevident. 2ustralia need to act to prevent issues such as dry land salinity withoutproper decisive action we ris the future of our agricultural industry.

REFERENCEShttp@AAhsc.csu.edu.auAagricultureAproductionAsalinityAsalinity.html [email protected]?A 46


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detailed the process of germination not specific to the species of Raphanus sativus (commonradish). This article will not form the basis of my research; however it will be useful detailingthe processes of germination formulating a background of my investigation.

http://www.biologyreference.com/Re-Se/Seed-Germination-and-Dormancy.html#ixzz3hLsoATi5

Bewley, J. Derek. "Seed Germination and Dormancy." Plant Cell 9 (1997): 1055–1066. ——,and Michael Black. Seeds: Physiology of Development and Germination, 2nd ed. New York:Plenum Press, 1994.

In this article J. Derek.and Michael Black review the affect of dormancy and the factors thateffect germination. The authors summarise the factors affecting the germination anddormancy of seeds. Though not specific to the species Raphanus sativus (common radish).This article will not form the basis of my research; however, it will help determine the factorsthat affect germination and dormancy within seeds.

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Salinity and It's Effect on the Germination Rates of Radishes- Ranier Knowles