ANALYSIS OF GROWTH AND GAS EXCHANGE OF PLANTS Lonchocarpus sericeus (Poir.) D.C. IN FLOODING FOR THE RECOVERY OF THE RIPARIAN FORESTS

Com o intuito de selecionar esp\ue9cies para utiliza\ue7\ue3o na recupera\ue7\ue3o de matas ciliares na margem do rio S\ue3o Francisco localizada no estado de Sergipe foi realizado um experimento com o objetivo de avaliar o crescimento e as trocas gasosas de plantas de Lonchocarpus sericeus (Poir.) D.C., submetidas a alagamento em condi\ue7\ue3o de viveiro. O experimento foi realizado no Viveiro Florestal do Departamento de Ci\ueancias Florestais, da Universidade Federal de Sergipe (UFS), no munic\uedpio de S\ue3o Crist\uf3v\ue3o-SE (11\uba01\u2019 de latitude S e 37\uba12\u2019 de longitude W, com altitude de 20 m), estado de Sergipe, Brasil, no per\uedodo de outubro de 2006 a janeiro de 2007 em condi\ue7\ue3o ambiente. Foi utilizado delineamento experimental inteiramente casualizado (DIC), em fatorial (2x7), dois tratamentos (controle \u2013 T0, plantas em capacidade de campo e alagadas \u2013 T1) e dias ap\uf3s alagamento (0, 15, 30, 45, 60, 75 e 90 dias). Para simular a condi\ue7\ue3o de alagamento, as plantas foram postas em vasos pl\ue1sticos de cor preta com volume de 5 L e mais substrato. Ap\uf3s, estes vasos foram acoplados a vasos com volume de 10 L, onde foi acrescida a \ue1gua at\ue9 atingir l\ue2mina d\u2019\ue1gua de 5 cm acima do colo das plantas. As plantas do controle permaneceram em vasos com volume de 5 L com substrato mantido na capacidade de campo. Nas vari\ue1veis n\ue3o destrutivas foram utilizadas 4 repeti\ue7\uf5es por tratamento, avaliadas a cada quinze dias, onde cada repeti\ue7\ue3o consta de 6 plantas, totalizando 24. Para as vari\ue1veis destrutivas foram utilizadas 4 repeti\ue7\uf5es por tratamento, avaliadas quinzenalmente a partir de 15 dias ap\uf3s o alagamento, onde cada repeti\ue7\ue3o consta de uma planta totalizando 24 plantas. Desta forma foram utilizadas 48 plantas por tratamento. As vari\ue1veis n\ue3o destrutivas foram altura, di\ue2metro do colo e n\ufamero de folhas. Enquanto as vari\ue1veis destrutivas analisadas foram massa seca da raiz e parte a\ue9rea, raz\ue3o da massa seca da raiz/parte a\ue9rea. Al\ue9m disso, foram realizadas an\ue1lises de trocas gasosas mensalmente, sendo avaliadas doze plantas por tratamento, com amostragem de duas folhas, completamente expandidas, por planta. As vari\ue1veis biom\ue9tricas foram submetidas \ue0 an\ue1lise de vari\ue2ncia e posteriormente ao teste de m\ue9dia (Tukey p <0,05), enquanto dos valores de trocas gasosas foram retirados os desvios padr\uf5es das m\ue9dias. Diante disso, observamos que o alagamento promoveu a redu\ue7\ue3o em altura e na raz\ue3o massa seca da raiz/parte a\ue9rea, a partir dos 30 dias ap\uf3s aplica\ue7\ue3o do tratamento. Al\ue9m disso, as plantas alagadas apresentaram modifica\ue7\uf5es morfol\uf3gicas como ra\uedzes advent\uedcias e hipertrofia das lenticelas, caracter\uedsticas de esp\ue9cies tolerantes ao alagamento. A taxa fotossint\ue9tica l\uedquida foi reduzida em 48,20% em rela\ue7\ue3o ao controle aos 60 dias. Todavia, apesar das redu\ue7\uf5es nas vari\ue1veis de crescimento e trocas gasosas, a esp\ue9cie Lonchocarpus sericeus mostrou-se promissora na recupera\ue7\ue3o de mata ciliar, por apresentar modifica\ue7\uf5es morfol\uf3gicas caracter\uedsticas de esp\ue9cies tolerantes ao alagamento.In order to select species for using in the restoration of riparian forests on the banks of the Sao Francisco River, in the state of Sergipe, an experiment was conducted to evaluate the growth and gas exchange of plants Lonchocarpus sericeus (Poir.) D.C., subject to flooding conditions in the nursery. The experiment was conducted at Forest Nursery, Department of Forest Sciences, Federal University of Sergipe (UFS), the municipality of S\ue3o Crist\uf3v\ue3o, (11 \uba 01 'S latitude and 37 \uba 12' longitude W, altitude 20 m) , state of Sergipe, Brazil, from October 2006 to January 2007 under ambient conditions. We used a completely randomized design (CRD), factorial (2x7), two treatments (control - T0, plants at field capacity and flooded - T1) and days after flooding (0, 15, 30, 45, 60, 75 and 90 days). To simulate the condition of flooding, the plants were placed in plastic pots of black color with a volume of 5 L and more substrate. Following these pots were attached to pots with a volume of 10 L, which was added water until it reaches a water depth of 5 cm above the top of the plants. The control plants kept in pots with a volume of 5 L substrate maintained at field capacity. In non-destructive variables were used four replicates per treatment evaluated every fifteen days, where each replicate consists of six plants, totaling 24. Destructive variables used were 4 replicates per treatment, determined biweekly from 15 days after flooding, where each replicate consists of a plant totaling 24 plants. Therefore, 48 plants were used per treatment. The non-destructive variables were height, diameter and number of leaves. While the destructive variables analyzed were dry weight of roots, dry weight of shoots and dry weight of root / shoot ratio. In addition, we carried out analysis of gas exchange on a monthly basis and evaluated twelve plants per treatment, with two sampling leaves, fully expanded, per plant. The biometric variables were subjected to analysis of variance and subsequently the average test (Tukey p <0.05), while the values of gas exchange were taken from the standard deviations of the mean. Thus, we observe that the flooding caused a reduction in height and dry mass of root / shoot ratio, from 30 days after treatment application. In addition, flooded plants showed morphological changes such as hypertrophy of adventitious roots and lenticels, characteristics of species tolerant to flooding. The net photosynthetic rate has been reduced by 48.20% compared to control after 60 days. However, despite reductions in growth variables and gas exchange species Lonchocarpus sericeus showed promise in the recovery of riparian vegetation, due to its morphological characteristics of species tolerant to flooding