Cerci Maria Carneiro

Growth of white clover seedlings treated with aqueous extracts of leaf and root of tough lovegrass

This study was carried out to investigate the effect of extracts of leaf and roots of tough lovegrass (Eragrostis plana) on seedling growth of white clover (Trifolium repens), in two experiments. The first experiment was conducted as a pilot test, in which two concentrations (30 and 60%) of leaf aqueous extract were tested. In Experiment II, source (leaf/root) and concentration (5 and 10%) of the extracts were combined. Distilled water was used as control in both trials. Fifty seedlings at 7 days of age were placed in gerbox containers on filter paper moistened with extracts and incubated at 25°C for 14 days. In the first experiment, percentage of normal seedlings decreased by 82.5% and 100% at the concentrations of 30% and 60%, respectively, which indicated the need to increase the dilution of the extracts. In the subsequent experiment, the extracts from the two sources, at 10% of concentration, reduced by 78% the percentage of normal seedling and increased the percentage of abnormal seedlings, which reached 27%. At 5% concentration, the leaf extract was the most deleterious treatment, resulting in greater mortality (M=27.6%) and abnormality (A=19.5%) of seedlings, compared to the root extract (M=4.8%; A=9.5%) and the control (M=2.4%; A=0.25%). The morphological changes caused by the extracts were radicle necrosis, retention of cotyledons and absence of secondary roots. The results suggest that allelopathic compounds from leaves and roots of tough lovegrass differ in chemical nature and/or concentration.

Desenvolvimento morfológico das gramas Esmeralda, São Carlos e Tifton 419

Avaliou-se o desenvolvimento morfologico das gramas Sao Carlos (Axonopus affinis), Tifton 419 (Cynodon dactylon x C. transvaalensis) e Esmeralda (Zoysia sp.), cultivadas em casa de vegetacao e colhidas integralmente aos 97, 118, 146, 174, 202, 230 e 258 dias de idade. A Tifton 419 mostrou os maiores comprimentos de estolao (83,3 cm), altura de planta (23,6 cm) e numero de folhas (12-24 cm-1 de estolao); as folhas mediram 6,7 cm x 1,9 mm (textura fina). Os estoloes da Sao Carlos atingiram em media 58,3 cm e foram os mais espessos (2,5 cm), com 2-4 folhas cm de estolao-1; as folhas mediram 10,9 cm x 12,3 mm (textura grossa) e a altura maxima da planta foi de 13 cm. A Esmeralda foi inferior quanto a altura (10 cm), comprimento de estolao (45 cm) e numero de folhas (7 folhas cm de estolao-1); as folhas mediram 6,2 cm x 3,7 mm (textura media). O acumulo de materia seca da parte aerea (mg planta-1) atingiu 12.100 (Sao Carlos), 8.700 (Tifton 419) e 3.500 (Esmeralda) e a relacao raiz:parte aerea foi de 0,33; 0,15 e 0,19, respectivamente. As distintas caracteristicas morfologicas das gramas podem subsidiar sua escolha para diferentes propositos.

Rebrota de Lotus spp. de diferentes hábitos de crescimento

This work aimed to compare Lotus spp. cultivars with different growth habits (L. corniculatus: cv. Sao Gabriel, semi-erect, cv. ARS2620, prostrate, and L. uliginosus: cv. Maku, decumbent), submitted to different height (4 - 8 cm) and cutting frequencies (15 d and 30 d), between the 95th and 233rd days old, grown in pot. Greater DM production (g. plant-1 of DM) was obtained under monthly cutting at 8 cm (Maku = 13.3; S. Gabriel = 11.5; ARS2620 = 7.3). Maku surpassed the others when intermediate levels (monthly cutting-4 cm; fortnighly cutting-8 cm) were used; harvests every 15 d and at 4 cm resulted in no difference among cultivars. The cv. ARS2620 showed the lowest height and the highest residual green canopy after defoliation. After the last cut, the cv. Maku overcame the other cultivars regarding crown diameter, DM of taproot, DM of soboles, DM of underground roots, and shoots. Lenient management favoured all the cultivars but they showed compensatory mechanism when they were submitted to intense and less frequent cutting or under frequent and less intense cutting. The three cultivars showed subterraneum stems of sobole type. The persistence of cv. S. Gabriel and the underground system of Lotus spp. were affected under intense and frequent cutting.

Morphological and anatomical aspects of birdsfoot trefoil and big trefoil

This study was carried out with the objective of describing the aerial and underground organs of birdsfoot trefoil [Lotus corniculatus (Sao Gabriel and ARS-2620 cultivars)] and big trefoil [Lotus uliginosus (Maku cultivar)]. The plants were cultivated in pots and harvested at 150 and 210 days after sowing. Stems, leaves and roots were prepared in according to conventional anatomical techniques. The anatomical structures of L. corniculatus and L. uliginosus differed in terms of pith cell integrity, starch content in the parenchyma root cell and underground stem cortex. The leaves were amphistomatic, with phenolic idioblasts, small vascular bundles and few conducting elements. The underground system was diffuse, with adventitious shoots that grew in two directions, had no cataphylls, emerged from the ground, and gave rise to aerial stems. The morphological characteristics of the shoot system of both species matched the recent descriptions of soboles.

Morphological development of Alfagraze cultivar and Crioula alfalfa populations selected at the seedling stage

The objective of this study was to compare two populations of Crioula alfalfa cultivars, selected by the length of the seedling second internode (Crioula-LI, long internode = 2.5 cm; Crioula-SI, short internode = 1.5 cm) with Alfagraze cultivar in order to verify the seedling morphology value for the selection of more prostrate plants. The plants were grown individually in pots in a semi-protected environment and harvested at 74, 104, 134, 164, 194 and 224 days. Crioula populations varied in terms of height, leaf area, root volume, dry matter yield, and the Crioula-LI population outnumbered that of Crioula-SI. For height, length of internode and primary stem, Alfagraze (45.1 cm, 2.1 cm and 16.7 cm) was similar to Crioula-SI (37.6 cm, 2.3 cm and 18.2 cm); however, the leaf area (2.028 cm2) and dry matter yield (20.3 g) did not differ from those of Crioula-LI (2.021 cm2, 21 g). The Alfagraze cultivar surpassed the Crioula population in terms of procumbency, crown diameter and crown stem number. At the flowering stage, the Crioula-LI cultivar had total stem number (61/plant) higher than Alfagraze (47/plant) and Crioula-SI (41/plant) cultivars. The length of the seedling internode is a promising marker for the selection of alfalfa, being a predictive factor for plant height, stem number, root volume and leaf area, and can be useful in the alfalfa breeding.