Qualidade fisiol?gica de sementes de gen?tipos de algodoeiro sob estresse salino

• Main Author: Lima, Leonardo Henrique Guedes de Morais
• Other Authors: CPF:02621094767
• Format: Others
• Language: Portuguese
• Published: Universidade Federal do Rio Grande do Norte 2014
• Subjects: Algod?o; Germina??o; Salinidade; Cotton; Germination; Salinity; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA MOLECULAR E DE MICROORGANISMOS
• Online Access: http://repositorio.ufrn.br:8080/jspui/handle/123456789/16775

Made available in DSpace on 2014-12-17T15:18:12Z (GMT). No. of bitstreams: 1 LeonardoHGML.pdf: 763178 bytes, checksum: c568f24d89429cee54a6bd18443ef3bc (MD5) Previous issue date: 2007-02-28 === The germination of cotton seeds and the seedlings emergency are generally delayed and reduced by the salinity. Although the cotton is considered a tolerant culture, it can suffer substantial reductions in regarding its growth and production when exposed to salinity condition. The aims of this study went evaluate the effect of the saline stress in the germination phase to four cotton genotypes (BRS Rubi, BRS Safira, BRS 201 and CNPA 187 8H), using different osmotic potentials generated with increment of sodium chloride (NaCl). The saline stress was simulated using NaCl aqueous solutions in the potentials: 0.0 (Control); -0.2; -0.4; -0.6; -0.8 and -1.0 MPa. The treatments were monitored by means of tests for analysis of seeds, germination, first counting, speed germination index, length of shoot, radicle length, dry weigth of embrionic axis and shoot/radicle ratio. The tests for germination, first counting and index of germination speed were accomplished using 50 seeds for repetition and for the study of length of shoot, radicle length, dry weigth of embrionic axis and shoot/radicle ratio were used 20 seeds by repetition. For both tests four repetitions were accomplished by genotype for each one of the potentials. The seeds of each repetition were involved in papers Germitest humidified with NaCl solution corresponding to the potential. The repetitions of both tests were maintained in a germinator with saturated humidity. The analysis were initiate four days after the induction of the saline stress. The evaluations of the first three variables analyzed were accomplished daily; the seeds were remove and counted when its germinated. For the length tests just the repetitions corresponding to the potential of NaCl 0,0 MPa were analysis 4 days after the beginning of the induction of the saline stress. The analysis of the repetitions of the potentials -0,2 and -0,4 and of the potentials -0,6, -0,8 and -1,0 MPa they were accomplished with 12 and 20 days, respectively. For accomplishment of the analisis of this test the shoot of the 20 plantules of each repetition was separate from the radicle and both parts were measured. The statistical analyses were performed using the GENMOD and GLM procedures of the SAS. For the variable germination, the cultivates CNPA 187 8H and BRS Safira stood out for the potential -0.8 MPa, with averages of 89% and 81%, respectively. The test of speed germination index to cultivate BRS Safira presented the largest averages for the two higher saline potentials. It was observed that the increase of the saline potential reduces the germination percentage and speed germination index. For each day of evaluation it was verified that the increase of the saline potential causes a reduction of the length both of the shoot and of the radicle. The radicle tends to grow more than the shoot until the potential -0,4 MPa === A germina??o de sementes de algod?o e a emerg?ncia de pl?ntulas s?o geralmente retardadas e reduzidas pela salinidade. Embora o algod?o seja considerado uma cultura tolerante, pode sofrer redu??es substanciais no seu crescimento e na produ??o quando exposta ? condi??o de salinidade. O objetivo deste estudo foi avaliar o efeito do estresse salino na fase de germina??o em quatro gen?tipos de algod?o (BRS Rubi, BRS Safira, BRS 201 e CNPA 187 8H), empregando-se diferentes potenciais osm?ticos, gerados com acr?scimo de cloreto de s?dio (NaCl). O estresse salino foi simulado, utilizando-se solu??es aquosas de NaCl nos potenciais 0,0; -0,2; -0,4; -0,6; -0,8 e -1,0 MPa. Os tratamentos foram monitorados por meio de testes para an?lise de sementes: germina??o, primeira contagem, ?ndice de velocidade de germina??o (IVG), comprimento de parte a?rea, comprimento de rad?cula, peso seco de eixo embrion?rio e rela??o rad?cula/parte a?rea. Os testes para germina??o, primeira contagem e IVG foram realizados utilizando-se 50 sementes por repeti??o; para o estudo de comprimento de parte a?rea, comprimento de rad?cula, peso seco de eixo embrion?rio e rela??o rad?cula/parte a?rea, foram utilizadas 20 sementes por repeti??o. Para ambos os testes, foram realizadas quatro repeti??es por gen?tipo para cada um dos potenciais. As sementes de cada repeti??o foram envolvidas em pap?is Germitest umedecidos com a solu??o de NaCl correspondente ao potencial. As repeti??es de ambos os testes foram conduzidas em germinador e a umidade mantida ao ponto de satura??o. As leituras das tr?s primeiras vari?veis analisadas foram iniciadas quatro dias ap?s a indu??o do estresse salino. As avalia??es foram realizadas diariamente; as sementes foram retiradas e contabilizadas ? medida que ocorria a germina??o. Para os testes de comprimento, apenas as repeti??es correspondentes ao potencial de NaCl 0,0 MPa foram lidas, quatro dias ap?s o in?cio da indu??o do estresse. As leituras das repeti??es dos potenciais -0,2 e -0,4 e dos potenciais -0,6, -0,8 e -1,0 MPa foram realizadas, respectivamente, aos 12? e 20? dias. Para a realiza??o das leituras deste teste, a parte a?rea das 20 plantas de cada repeti??o foi separada da rad?cula e ambas mensuradas. As an?lises estat?sticas foram efetuadas, utilizando-se os procedimentos GENMOD e GLM do SAS. Para a vari?vel germina??o, as cultivares CNPA 187 8H e BRS Safira destacaram-se para o potencial -0,8 MPa, com m?dias de 89% e 81%, respectivamente. Foi observado que o aumento do potencial salino reduziu a porcentagem do IVG. Para cada dia de avalia??o, verificou-se que o aumento do potencial salino provoca uma redu??o do comprimento da parte a?rea e da rad?cula. A rad?cula tende a crescer mais que a parte a?rea at? o potencial -0,4 MPa