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Abstract SUMMARY The present investigation was lanned to study the causal of Sore-shin disease of cott the effect of some physiological, physical and ch factors geverning the outbreak and control of the dis caused by Rhizoct- ~ lQ orticium)solani,on cotton pl, t s, The findings can be summarized as follow:- 1- The tested isolate of -R (-Co-rt-ici-um..•. solani caused cotton Sore-shin disease with different d grees. The percentage of both pre-and post-emergence ing off increased by increasing-’den~i ty • 2- Sodium nitrite followed by sodium and casin were the best for supporting linear and J- Fructose, maltose and galactose ear and amount of growth. 4- The optimum temperature for the Ii ear growth and dry weiof growth. hi~est linght was 25°C. ’- The highest pereentage of cotton s ed germination in Petri dishes was obtained from seeds ex sed to 600e for 10 minutes (l 6- The highest percentages of healthy survivals were obtained from seeds exposed to 600e for 5 followed by 500e for 15 min. Com 7- seed exposed to 6aoe for 15 root and seedling length of • or 700C tor 15 min. with the control. e the highest mean of cted plants, while 8 - 9 - ;10- = 10 a exposing to 500C for 5 min ve the highest mean of root length s , On the other hand. the highest mean dry weight as obtained for un-infected plants from exposure 0 600e for 10 min and to 70°C for 10 min of infected lants, ~»onophenols were always les in healthy hypocotyls of seedling from seeds exposed 0 hot air treatment. Reduction varied depending on t e temperature and duration of exposure. Hot air trea ent resulted in a reduc_ tion of monophenol content i the infected hypocotyls ’than control treatment, Polyp enols, increased in all treatments, in varying degree , compared with the control. Orthodihydroxy phenols, increased in respone to infection of plants from seed not exposed to hot air treatment. Amino acids, increased in un- nfected plants exposed to hot air treatments with the xception of few treatments. Infection resulted in some henols, in all durations of t only in 5 min exposure of Polyphenols, increased in the ings from seed exposed to hot infected seedlings showed different hot air treatments. of the orthodihydroxyp- 5000 treatment, and 600e and 700e in leaves. eaves of healthy seedltreatments. Leaves of ble responses to the Monophenols, decreased ~-- -------_._--~-, ._~~~~~- L5- Seeds soaked in 10 ppm GA3 gave the highest percentage of seed germination, while NAA at 25 ppm decreased seed germination percentage in sterilized soil. 16- The highest percentages of healthy survival plants were obtained from seeds treated with GA3 at 5 ppm, and NAA a,; 100 ppm. 17- GA j at 5 ppm and NAA at 100 ppm reduced root length 18- Growth regulators, reduced the average of dry weight of healthy plants, while did not affect infected plants. 19 Phenolic compounds in hypocotyls of seeds treated with growth regulators, decreased in all treatments except in case of the highest concentrations of both GAJ and lIJ.A.as response to il~fection, similar to the case of the •••. ..._ ecids. in ~ec”ted. b.7pocotyl.s were always less tIIIa tIIId t4 ’UIe CGIIlro1 as a resul.t of treatment with e ••.~.-tara. elKCept’those receiY1nB the highest o _~:Lon or .aA, (ZOO ~). ~ ]”a ~_. tIlere -., a pOll~1;:1Yecorre1A1;i.on bet:ween ’the o.MllL:tat;icm o~ ”-31 or IIAAand. phen*l.1.c cOIIlpound8 i.n -.J.tiV’ tieaues. ezcaept .anopheu.o1a which showed ’the ., -- III = contrast!This correlation was noticed in infected tissues only in case of total phenols. In case of total free phenols, infection Was accompanied by a reduction in the ti,ssue content of phenolic compounds in the respecti ’Ie healthy control 22 - Growth regulators, :Lnduced increase in wnino acids in healthy tissue in all treatments compared with the control. On the other hand, those amounts showed 4 vuriation among infected leaves due to the kind of gro~h regulators and the concentration applied. a- Soek1ng aeed.ain different concentrations of GA J and Iii tended to increase all sugar fractions of the healthy hypocotyls ,::omparedwith healthy control. except GAJ at 5 ppm t:reatments. Infection tended to in- (~rease the carbob,ydrate content of 1nf’ected. seedlings 1•• ci·]]Z the nao-r••dUC1ng sugar :traction •• The tota~ ••I_it. ~ were -ore ’than doubl.ed :Ln the IOO ppm .:11&&.) - :LDcreaaed !aboat 75%in the 5 PIa GA 3 trea- .•• • - - - -~~- ~-...- ~~~ .b,;L&1eCJl,i perce- .~,. -- Cd .hea1-u..?’ -.a;iw:1.~ p].an:ts (60_42~)_ ••. - .JBr-n:~ re ••I1:~ J..:+l &. .a:rop o:r the ’ta1:a1 ADd ::I”J.OEI.-r-ed._ ”’-e -e’ra 1..n ~ :le c~ ~Q ~e UD.-1n%’- ..25 - ..26 - 27 - ’”:~~1.12 = sugar fractions. Sugar conlent was alway less in the leaves of infected plants than those of the un-infected ones at all NAA and GAJlevels except in 5ppm treatment. Increasing N and K level led to significant increase of seed germination percentage while the treatment of (N2PJK J ) gave the highest percentage of seed germination. ,;N2PI~ (treatment) gave the highest healthy surVivals percentage, it was found that a balance between the three fertilizers (:N”,Pand K) is required to obtain the highest percentage of healthy survival plants • P2 .,.-~, NJP2’ NJ~ and NJP2KI treatments gave the highest average length of un-infected seedlings, while NI ~ PJ ’ NIP) , NIK) t PJKJ and NrP2KJ treatments gave the highest average length of infected seedlings Adding fertilizers at levels of PJ t ~,NJP2t P2KI1 HJK2 and N2PrKr treatments resulted in the highest dry weight of un-infected seedlings. while B)P2’ NJKJ• p~ aDd .IP2~ u-ea~-ts gare ”the hishes1; dr:t weight d i.D:fec1ied. seedJ1Dp. llr:rP aud K •.1i ~;rer_~ ..-~_ hacl -~ err_’t: •••. ’t~ -tal. and po1ypheno1s in _poco’C7]..s 0% pJI-*_ 1’rGa 1DZ:; 1-- 32- ected and non-infe.Hted soil. For orthodihydroxyphen- 01, infection resuli;ed in a slight decrease in most treatments. Monophellols increased as a result of infection As regard amino acids, infection was most accompanied by a DROP in their amounts when fertilizers were added. Monophenols increased in leaves of un-infected plants in (N) levels, P2,PJ and K) treatments. Infection reaul ted in a redu.ction in monophenols in the different levels of N ,Il and K. Similar trend was found for polyphenols, total free phenols and total amino acids, w:bich were presen1; at h.J.gher concentration in infected o:eC\CIIl l.eayea ~l -u. leayes of plants receiving no JlP8Cifi.c DUtri.~m regi.aes. Ul %ertiJiser U’l1IB”-Dtsresulted in an :increa.se in JICT-re’wri uS BUfP’1Ir’S aDd total. soluble sugars of un- ~ec’Hd seecni.” eaept those receiving B1P:rKJ and JIi’iK) ’Rea- ,,-. ~O’&IU801ub~e sugars and reduoing -S” were ~ ~ in theun-1nteC’ted plants thaD ’C••• :I.:r 18ge1 1.n ~ecfied cc:m:tiro1. Po1;aasiwa was aeeampa- D..i.rM by an ~ rollOifed. by a DROP :Ln -the 1;o1;;a.l. ~ea.”Sc 18 ~ ~~ec”,,-a. ---t. ~_’t::ed. b:rpee= 114 = Increasi g the sup:ply of N,P and K fertilizers exhibited an nitial rise in reducing sugars followed by DROP in nfected h,Y’pocotyls.Inc: easing K- level led tyls. In N and P caused a reduction in total solublo wl-infected and infected hypocotyls. to an in rease in sugar fraction and in contrast with P-levels while N-levels increased and then decreased sugar co tents. ~; _ Fertili ation treatments led to a reduction in sugar in un-infected leaves compared with the control. :fection resul tE~din a DROP in sugar cont ent, I dir~erent trea~ents of fertilization. ~ - ,tiu._ decrees_ in un-infected hypocotyls reg¥’tl””’!” .•••• ~ trea~t. Infection caused a reduction in JIi.~””il level1J1 most treatments. Nutritional trea- .••••. ” Efl=au..L~ed. in. a aUgb:t DROP o-r Phoaphoroua in ~. ~ec1;ion led to an increase in P-contedJ1~””,,, ueatments. Potassi\DD was pres- 1IUo6U~r CGl$eeu:tratioDSin lqpocot.Y1s as a res- ~ctri.’t:l••. laud acc•• ula”,ecl to a higher level ••• preseDt 111iDtected cottQD leaves at tiana hiper ’thaD in ””infected tissues of plants ceiving s:Lmilar treatments. Non-inoculated plants ceiving different fertilizers always contained hi er amounts of Potassium compared with the non-trea ed control, with no specific trend. |