Silvana de Paula Quintão Scalon

Crescimento inicial de mudas de Bombacopsis glabra (Pasq.) A. Robyns sob condição de sombreamento

This experiment was carried out to study the growth of Bombacopsis glabra (Pasq.) A. Robyns seedlings under different light intensities. The germination capacity of the seeds was determined by the index and percentage of germination speed of a hundred seeds (1 seed/sac). After 40 days, seventy-five saplings were transferred to 50% and 30% shade and beds under direct sunlight. Sapling development was carried out in randomized block design with three repetitions of five saplings, with stem height and lap diameter being evaluated on the 61 st , 82 nd , 103 rd and 124 th day after sapling emergence. Chlorophyll content a, b, total and ratio a/b; dry mass of the plant (DM), leaf area (LA), relative growth rate (RGR), leaf area rate (LAR) and net assimilating rate (NAR) and survival sapling percentage were measured on the 103 rd and 124 th days, when the experiment was concluded. The seeds presented 95% of germination and a high index of germination speed (1.7). The saplings presented 100% of survival in all the treatments. Shade levels did not affect sapling survival, stem diameter, leaf area, chlorophyll a and b, RGR, LR and LAR during the studied intervals. The saplings grown under 50% shadow presented a higher height, larger concentration of total chlorophyll and a lower a/b ratio. Bombacopsis glabra propagates easily, presenting a good development at full sunlight and enduring 30% and 50% shade.

GERMINAÇÃO E CRESCIMENTO DE MUDAS DE PITANGUEIRA (Eugenia uniflora L.) SOB CONDIÇÕES DE SOMBREAMENTO

The objectives of this work were to evaluate germination capacity of Eugenia uniflora L. seeds and the growth of seedlings under shade conditions. The experiment was carried out at Experimental Research Area of the UNIGRAN ¾ Dourados, MS. Germination test was done with 300 seeds and germination percentage and emergence speed index were evaluated. At the third month after emergence, the seedling growth experiment was carried out in a randomized block design with three treatment (50% and 70% of sunlight and at full sunlight) with four replications of 15 seedlings each treatment. When seedlings presented 4, 5, 6 and 7 months of age, height and stem diameter were evaluated and at the final of the experiment, total dried weight of seedlings (g), leaf area (dm2), leaf weight rate - RPF (g/g) and leaf specific weight - PEF (g/dm2). Eugenia uniflora L. is specie of easy propagation by seeds presenting 65,7% of germination and emergence speed index of 3.34, and seeds began their germination process 23 days after sowing. Seedlings growth better under full sunlight conditions, where they showed biggest height, stem diameter, dried weight and leaf area.

Tratamentos para quebra de dormência, temperaturas e substratos na germinação de Adenanthera pavonina L.

Desenvolveu-se, esse trabalho, com o objetivo de avaliar tratamentos pre-germinativos para quebra de dormencia bem como a temperatura e substratos ideais para a germinacao de sementes de Adenanthera pavonina L.. No primeiro experimento as sementes foram tratadas com acido sulfurico durante 10 e 20´ (H2SO4), acido sulfurico 20´ + imersao por 24 horas em acido giberelico (GA) 100mg.L-1; acetona por 20´ e testemunha. A incubacao foi realizada em temperatura alternada de 20/30°C, e temperaturas fixas de 25°C e 30°C. No segundo experimento, as sementes foram tratadas com acido sulfurico 15´ e a semeadura nos substratos sobre papel, rolo de papel e entre areia, nas temperaturas de 18oC, 20/30oC, 25oC e 30oC. Observaram-se maiores valores de germinacao nas sementes tratadas com H2SO4 por 10´ (83%), nao havendo diferenca significativa entre as temperaturas, em ambos os experimentos. Com relacao ao substrato foi observado que as sementes germinaram melhor nos substratos sobre papel e em rolo de papel (media de 86%). Entretanto, no segundo experimento, o IVG foi maior a 18°C (1,22) e no substrato sobre papel (1,33), nao variando significativamente da temperatura alternada 20/30°C. A maior porcentagem de germinacao na primeira contagem variou de 30% (18o C) a 13% (30o C), sendo maior em rolo de papel (43%). O numero de dias para alcancar 50% de germinacao variou de 3,33 a 13 dias nos tratamentos com H2SO4. Nao foi observada diferenca significativa no peso seco das plântulas (1,08g), submetidas a diferentes temperaturas e substratos.

Armazenamento e germinação de sementes de uvaia Eugenia uvalha Cambess

Com o presente trabalho, objetivou-se testar o tempo e temperatura de armazenagem e tratamentos pre-germinativos na germinacao de sementes de uvaia (Eugenia uvalha Cambess). As sementes foram separadas em lotes de 100 unidades, que foram pesadas e, em seguida, armazenadas em temperatura ambiente (30±2oC) e em geladeira (13± 2oC), sendo acondicionadas em frascos de plastico com tampa rosqueada. No inicio do experimento e a cada 30 dias (30, 60, 90 e 120 dias de armazenamento), as sementes foram imersas por 30 minutos em agua quente ou GA 125 mg.L-1 e GA 250 mg. L-1 por doze horas, e aquelas sem nenhum tratamento serviram como testemunha; em seguida, foram semeadas em recipiente contendo terra + areia (1:1) como substrato. Foram avaliados a percentagem de emergencia e o indice de velocidade de emergencia. O experimento foi conduzido em esquema fatorial 2 (temperaturas de armazenamento) x 4 (tratamentos pre-germinativos) x 4 (periodos de armazenamento) em delineamento inteiramente casualizado com quatro repeticoes de 25 sementes. As sementes armazenadas em refrigeracao apresentaram, em geral, maior percentagem e indice de velocidade de emergencia. As sementes de uvaia recem-colhidas nao emergiram ate os 200 dias de observacao. Sob armazenamento a temperatura ambiente, houve menor emergencia (32,14%) que aquelas sob refrigeracao (40,37%). Quanto aos periodos de armazenamento, a maior emergencia foi observada nas sementes armazenadas por 60 dias sob refrigeracao (65,56%) e 90 dias sob temperatura ambiente (52,03%). GA 125 mg.L-1, sob refrigeracao, e GA 250 mg.L-1, sob temperatura ambiente, foram os tratamentos pre-germinativos com maior emergencia. O indice de velocidade de emergencia foi maior nas sementes armazenadas sob refrigeracao, e aos 60 dias (0,099), esse indice foi maior, comparado com as sementes por 90 dias (0,069) sob temperatura ambiente. As sementes imersas em giberelina alcancaram o maior IVE (acima de 0,05).

Study of Acari and Collembola Populations in Four Cultivation Systems in Dourados - MS

The impact four cultivation systems on the soil fauna was studied, using Oribatida and Gamasida acarids as bioindicators and collembolan. The research was carried out in experimental fields, located in EMBRAPA - CPAO in Dourados, Centerwest of Brazil from July 1997 to December 1999. The constant pasture system presented smaller impact on the soil fauna followed by agricultural cattle rotation and a direct plantation system. In the conventional plantation series, the populational density of the mesofauna organisms was low, especially collembolan families.

Biometry of fruit and seeds and germination of Magonia pubescens ST.Hil (SAPINDACEAE)

Magonia pubescens is a common native tree species of Brazilian savanna with a great utilization potential because of its economic and ecologic characteristics. The aim of this work was to evaluate the biometrical characteristics of fruit and seeds of this species and its germination potential. It was studied 28 fruit and 293 seeds originated from trees placed in Aquidauana - MS. The study was conducted in the Vegetable Physiology Laboratory and nursery conditions belonged to Faculdade de Ciencias Agrarias (FCA) of Universidade Federal da Grande Dourados (UFGD). There was a large variation in the size, weight and the seed-number of the fruit that presented middle values 6,66 cm of length, 8,14 cm of diameter, 248,21g fresh mass and 13,14 seeds. On the other hand, the seed size variation was smaller than the fruit size variation. The seeds presented middle values 4,81 cm of length, 8,44 cm of width and 3,5 of fresh mass. For the germination study, the seeds received the following treatments: 1) KNO3 1% 24h; 2) KNO3 2% 24h; 3) GA 500 mg. L -1 24h; 4) GA 250 mg L-1 24h; 5) Water 24h; 6) Control. The experiment was set up according to a three-replicate randomized complete design with 6 treatments. The treatment of immersion in water for 24 hours promoted the highest values of emergence percentage (80%). The gibberellins promoted the highest values of aerial part height (meddle of 14,7cm). The highest values of fresh and dry aerial part matter were observed in seedlings originated from seeds treated with GA 500 mg. L -1 (1,26 and 0,24g, respectively). The highest values of fresh and dry cotyledons matter were observed in seedlings originated from seeds treated with KNO3 1% 24h (7,63 and 1,81, respectively). It is recommended to pre-soak of the seeds in water or GA for 24 hours to obtain a greater number of seedlings.

Composição química e atividade alelopática do óleo volátil de Hydrocotyle bonariensis Lam (araliaceae)

Os oleos essenciais sao liquidos aromaticos obtidos de materiais vegetais (flores, folhas, ramos, sementes, ervas, madeira, frutos, raizes e cascas), sendo constituidos por misturas complexas, dentre outras, de terpenoides que podem conter ate 100 ou mais compostos orgânicos. Os terpenos encontrados com maior frequencia nos oleos essenciais sao os monoterpenos, sesquiterpenos e com menor frequ-encia os diterpenos. Seus constituintes terpenicos podem apresentar diversas funcoes orgânicas, como alcoois, cetonas, eteres, esteres e aldeidos. Os terpenos possuem, tambem, diversas funcoes nas plantas atuando como fitoalexinas, repelentes de insetos, agentes de atracao polinica, agentes de defesa contra herbivoros, feromonios, hormonios vegetais, moleculas de sinalizacao e aleloquimicos.

Sensibilidade à dessecação e aoarmazenamento em sementes de Eugenia pyriformis Cambess. (uvaia)

This study aimed to evaluate the desiccation sensivity and storage and longevity behavior of uvaia seeds (Eugenia pyriformis Camb.). It was carried out with seeds from fruits collected at Amambai-MS city. To study the desiccation sensitivity, a protocol based on the dehydration level on each five percentage points reaching 45, 40, 30, 25, 20, 15, 10 and 5% seeds moisture contents was used. To study the longevity of seeds during storage were tested the following conditions of cold and dry chamber (16 ± 1C o / 40% UR), refrigerator (5 ± 1C o) and freezer (-18 ± 1 o C) for 30 days and seeds sown soon after processing constituted the control treatment. Seeds were sowed between sand at 20/30 oC at 10 h light/14 h darkness in B.O.D. Uvaia seeds are desiccation sensitivity and can not tolerate drying below 5% moisture content. The moisture content decrease caused the reduction on the fresh mass, primary root length, hypocotyls length and on the seedlings total length reduction as in the germination medium time. The fresh seeds presented approximately 77% germination and the 5% moisture content dehydration reduced the germination to 15%. The storage conditions under low temperatures and seeds dehydration reduced seed germination, thus indicating a recalcitrant behavior of uvaia seeds.

Seed germination and vigor of corn plants submitted to saline stress induced by different salts

O objetivo do trabalho foi avaliar o efeito do estresse salino induzido por diferentes potenciais osmoticos das solucoes de NaCl, KCl e CaCl2, na germinacao de sementes e no vigor de plântulas de milho. O trabalho foi constituido por dois experimentos realizados no Laboratorio de Sementes da Universidade Federal da Grande Dourados e em casa de vegetacao da Embrapa Agropecuaria Oeste, Dourados-MS. O delineamento experimental utilizado foi inteiramente casualizado, em arranjo fatorial 3 x 6, com quatro repeticoes, sendo o primeiro fator constituido pelos sais e o segundo pelos potenciais osmoticos: 0,0; -0,2; -0,4; -0,8; -1,2 e -1,6MPa. Foram analisadas as variaveis: Experimento 1 - porcentagem de germinacao, comprimento de parte aerea e comprimento da raiz primaria; Experimento 2 - altura final de planta, comprimento radicular, diâmetro de colmo, area foliar, teor de clorofila e massa seca de parte aerea e de raiz. A germinacao nao foi afetada pelo estresse salino. A diminuicao do potencial osmotico nas solucoes de KCl e NaCl, causou decrescimos no comprimento de parte aerea e acrescimos no comprimento da raiz primaria. A condicao de estresse provocada pelos sais proporciona comportamento diferenciado no vigor de plântulas de milho. O efeito salino do NaCl e maior nas caracteristicas altura de planta, comprimento radicular, area foliar e massa seca de raiz.

Crescimento inicial de mudas de pau ferro (Caesalpinia ferreaMart. ex Tul. var. leiostachya Benth.) sob diferentes regimes hídricos

The objective of this study was to evaluate the initial growth of Caesapinia ferrea Mart ex. Tul var. leiostachva Benth (Fabaceae-Caesalpinioideae) under four hidric regimes (overflow, 70, 40 and 12.5% of field capacity). The seedlings were submitted to the treatments after 60 days of age. The experimental delineation was completely randomized with four repetitions of eight seedlings for treatment. After 7 days of permanence under treatment, the evaluations had been initiated. The diameter (6,5 mm), relative water content (52.45%), specific foliar area (174.58 g cm2), rate of relative growth (0.0160 g g-1), liquid assimilated rate (0.0004 g dm-2 days-1) and specific weight of leaf (0.0062 g cm2) did not vary statistically between the treatments. The seeds under 70% CC had presented greater height (84.6 cm), size of the root (28.9 cm), dry mass of the root (6.24 g), foliar area (376.0 cm2), dry mass of the leaf (1.98 g), dry mass of the aerial part (8.27 g) and content chlorofile (31.67 ig cm2).The ratio of specific weight (0.2368 g g-1) and the nitrogen content (0.37 g kg-1) was higher under 12.5% CC. The ratio of foliar area (35.09 g g-1) was lower under 12.5% CC. Therefore, the best condition for the production of the seedlings is at 70% of the field capacity.