Etiane Caldeira Skrebsky

Effect of cadmium on growth, micronutrient concentration, and δ-aminolevulinic acid dehydratase and acid phosphatase activities in plants of Pfaffia glomerata

Plântulas de Pfaffia glomerata (Spreng.) Pedersen foram cultivadas em cinco niveis (0, 20, 40, 60 e 80 μM) de cadmio (Cd) em um sistema hidroponico durante 7 d, visando-se analisar o crescimento, as concentracoes de micronutrientes, clorofilas e carotenoides, bem como as atividades da desidratase do acido δ-aminolevulinico (ALA-D; E.C.4.2.1.24) e fosfatase acida (AP; E.C.3.1.3.2) nas plantas. A concentracao de Cd, na parte aerea e raizes, aumentou com o incremento dos niveis de Cd. A concentracao de Cd nas raizes foi, em media, 12 vezes maior do que na parte aerea. O comprimento das raizes nao foi afetado pelos tratamentos de Cd. Em contraste, a biomassa seca da parte aerea e raizes aumentou significativamente pela adicao de 20 e 40 μM Cd. Alem disso, a biomassa seca total das plantas somente diminuiu no nivel de 80 μM Cd em relacao a das plantas-controle. Por outro lado, a biomassa radicular diminuiu significativamente pela adicao de Cd a niveis superiores a 40 μM. Constatou-se resposta dependente do orgao e do micronutriente a toxicidade de Cd. As concentracoes de Zn e Cu na parte aerea e raizes nao foram alteradas pela presenca de Cd. A absorcao de Mn foi diminuida pelo estresse de Cd, porem sua translocacao nao foi alterada. Um efeito sinergistico do Cd na concentracao de Fe nas raizes foi observado nos niveis de 20 e 80 μM Cd. As atividades da ALA-D e AP foram diminuidas com o incremento dos niveis de Cd, porem a ALA-D foi mais afetada. Naquelas concentracoes de Cd, a concentracao de clorofila tambem foi diminuida. Houve uma correlacao positiva entre as concentracoes de carotenoides e clorofila. Os resultados indicam que a P. glomerata parece ter algum grau de tolerância ao Cd.

Physiological and oxidative stress responses of four potato clones to aluminum in nutrient solution

Aluminum toxicity is a serious problem in Brazilian soils and selecting potato clones is an important strategy to produce this crop on these kinds of soils. Potato clones, Macaca, SMIC148-A, Dakota Rose, and Solanum microdontum, were grown in a nutrient solution (pH 4.0) with 0, 50, 100, 150 and 200 mg Al L-1. After 7 d, Al concentration in both root system and shoot of all clones increased linearly with increasing Al levels. Based on relative root growth, S. microdontum and SMIC148-A were considered Al-tolerant clones, whereas Macaca and Dakota Rose were considered Al-sensitive. Shoot growth in Macaca linearly decreased with increasing Al levels. Root H2O2 concentration in both Al-sensitive clones increased with increasing Al supply, whereas in Al-tolerant clones it either decreased (SMIC148-A) or demonstrated no alteration (S. microdontum). Shoot H2O2 concentration increased linearly in Macaca, whereas for Dakota Rose it showed a quadratic relationship with Al levels. On the other hand, shoot H2O2 concentration in the Al-tolerant clones either demonstrated no alteration (S. microdontum) or presented lower levels (SMIC148-A). Root catalase (CAT) activity in both Al-sensitive clones increased with increasing Al levels, whereas in Al-tolerant clones it either demonstrated no alteration (SMIC148-A) or presented lower levels (S. microdontum). Shoot CAT activity in the S. microdontum increased curvilinearly with increasing Al levels. In all potato clones, chlorophyll concentration showed a curvilinear response to Al supply, where in Al-sensitive clones it decreased upon addition of Al exceeding 100 mg L-1, but in SMIC148-A it increased at levels between approximately 100 and 150 mg L-1, and decreased in S. microdontum regardless of the Al level. Carotenoid concentrations in the Al-sensitive clones were linearly decreased with increasing Al levels. Aluminum supply caused root lipid peroxidation only in the Al-sensitive clones, whereas in the shoot it increased linearly in the Al-sensitive clones and in S. microdontum it only increased at around 50 mg L-1. Most of root protein oxidation was only observed in the Al-sensitive clones. However, shoot protein oxidation was increased with increasing Al levels for all potato clones. These results indicate that oxidative stress caused by Al in potato may harm several components of the cell, mainly in Al-sensitive clones.

Sacarose e período de cultivo in vitro na aclimatização ex vitro de ginseng brasileiro (Pfaffia glomerata Spreng. Pedersen)

Pfaffia glomerata (Spreng.) Pedersen is an extensively used plant in popular medicine due to its phytotherapic characteristics. Due to low photosynthetic capacity of plants cultivated in vitro, an extra source of carbohydrates is required to supply their metabolic demands. The growth rate of roots and shoots of P. glomerata are different during the in vitro cultivation. The objectives of this study were to evaluate the effect of sucrose levels and the duration of in vitro growth on ex vitro acclimatization of P. glomerata seedlings. Treatments consisted of a bifactorial combination (5x2) of five sucrose levels (15, 30, 45, 60 and 75g L-1) and two periods of in vitro cultivation (25 and 32 days after inoculation). In the in vitro cultivation, the experimental unit consisted of a test tube containing 10mL of MS medium and a nodal segment, from in vitro cultivated plants, of 1,0cm in length without leaves. The acclimatization scheme consisted of ex vitro cultivation by four successive phases: (i) opening of the test tube and subsequent cultivation in growth room for three days; (ii) seedlings subcultivation to Plantmax substrate and cultivation in growth room for 21 days; (iii) seedlings transfer to partially shady natural environment for 24 days; and (iv) seedling subcultivation to soil under field condition. The greatest plant growth by increasing the sucrose availability (levels among 45 and 60g L-1) during the in vitro growth contributed to acclimatization. Regardless of duration of the in vitro growth, the seedlings obtained and efficient acclimatization. The acclimatization procedure was 100% efficient on seedling production of P. glomerata.

Substratos na aclimatização de Pfaffia glomerata (Spreng) Pedersen produzida in vitro sob diferentes doses de sacarose

This work was aimed at selecting substrates on the ex vitro acclimatization of Pfaffia glomerata produced in vitro under different sucrose levels. The treatments consisted of a bifactorial combination (5x3) between five sucrose levels (15, 30, 45, 60, and 75g L-1), present in the in vitro culture, and three substrates [Plantmax®; Plantmax® + soil (1:1 v/v), and vermiculite (middle size) + soil (Paleudalf) (1:1 v/v)] used in the ex vitro acclimatization steps. Physical and chemical evaluations of the substrates were carried out as well as evaluations of plant growth and survival for both in vitro and ex vitro cultures. Plants obtained from in vitro cultures in the presence of 45 to 60g L-1 sucrose showed better ex vitro acclimatization. The substrate combinations vermiculite + soil and Plantmax® + soil gave rise greater growth to plants during the last acclimatization step (partially shady natural environment), probably due to having greater total porosity. However, the isolated use of Plantmax® increased the plant survival under field conditions because this substrate showed the greatest values for water retention capacity, easily available water and available water.

Sacarose e nitrogênio na multiplicação in vitro de Pfaffia glomerata (Spreng.) Pedersen

Pfaffia glomerata (Spreng.) Pedersen, known as brazilian ginseng, is an extensively used plant in folk medicine due to its phytotherapic characteristics. This work aimed to determine the best combination of sucrose (30, 45 and 60 g L-1) and nitrogen (50, 75, 100 and 125% of the strength of MS medium) on micropropagation of P. glomerata. In 30 days of cultivation, sucrose ranging from 40 to 45g L-1 and nitrogen at 50% increased the height and the number of nodes. The number of shoots was greater at concentration of 55g L-1 sucrose combined with 70% N. The dry matter of roots, aerial parts, and of the whole seedling was increased on 50% N and 45g L-1 sucrose. Altogether the halved concentration of nitrogen and the increased concentration of sucrose to 45g L-1 increase the height, the number of nodes and the shoots as well as biomass production improved due to an enhancemednt of carbon use.

Caracterização das exigências nutricionais de mudas de Pfaffia glomerata em Argissolo Vermelho distrófico arênico pela técnica do nutriente faltante

Este trabalho teve por objetivo caracterizar as exigencias nutricionais de mudas de ginseng brasileiro (Pfaffia glomerata (Spreng.) Pedersen) em Argissolo Vermelho distrofico arenico pela tecnica do nutriente faltante. Plantas de P. glomerata produzidas in vitro e aclimatizadas ex vitro foram usadas como material inicial para o experimento em casa de vegetacao. Aos 10 dias apos o transplante para o solo, atraves de solucoes nutritivas, foram realizadas as adubacoes correspondentes a nove tratamentos: controle (sem adubacao), adubacao completa (com macro e micronutrientes) e as omissoes individuais de N, P, K, Ca, Mg, S e dos micronutrientes (Zn, B, Cu, Fe, Mn e Mo). Aos 60 dias de cultivo, avaliaram-se os parâmetros de crescimento das plantas. O numero de folhas por planta foi o parâmetro de crescimento mais afetado pela ausencia dos nutrientes N, K, S e P na adubacao. O efeito da omissao dos nutrientes na adubacao foi diferenciado quanto a particao de biomassa entre os orgaos da planta. A biomassa acumulada pela parte aerea obedeceu a seguinte ordem decrescente, em relacao a omissao do nutriente: Mg @ micronutrientes > Ca @ adubacao completa > P > S > K > N @ controle. Ja a biomassa radicular obedeceu a seguinte ordem decrescente: Mg @ adubacao completa ³ P ³ micronutrientes ³ S ³ Ca > N > K @ controle. Plantas jovens de P. glomerata cultivadas em Argissolo Vermelho distrofico arenico apresentaram grande reducao no crescimento pela ausencia de N, K, S e P na adubacao. As omissoes de Mg e dos micronutrientes na adubacao nao foram limitantes para o crescimento das plantas jovens.

Micronutrient concentration in potato clones with distinct physiological sensitivity to Al stress

The objective of this study was to evaluate the effects of aluminum (Al) on the zinc (Zn), manganese (Mn), iron (Fe) and copper (Cu) concentrations in four potato clones (Macaca and Dakota Rose: both Al-sensitive clones; and SMIC148-A and Solanum microdontum: both Al-tolerant-clones), grown in a nutrient solution (pH 4.00) with 0, 50, 100, 150 and 200mg Al L-1. Root Zn and Fe concentrations decreased linearly with the increase of Al levels in Macaca, SMIC148-A and Dakota Rose and increased linearly in S. microdontum. Shoot Zn concentration showed a quadratic relationship with Al in S. microdontum and SMIC148-A, but a curvilinear response in Dakota Rose. Shoot Fe concentration showed a quadratic relationship with Al in S. microdontum, SMIC148-A and Dakota Rose. Root Mn concentration decreased linearly in Macaca and SMIC148-A, and increased linearly in S. microdontum with Al levels. Mn concentration showed a quadratic relationship with Al in roots of Dakota Rose and in shoot of SMIC148-A, and increased curvilinearly with Al levels in shoot of Dakota Rose. In shoot, there was no alteration in Zn, Fe and Mn in Macaca and Mn concentration in S. microdontum. Roots and shoot Cu concentration increased linearly in Dakota Rose, and showed quadratic relationship with Al in Macaca. Roots Cu concentration showed a quadratic relationship with Al levels in S. microdontum and SMIC148-A. Shoot Cu concentration increased linearly in S. microdontum, and decreased linearly in SMIC148-A. Therefore, the excessive Al accumulation affected the uptake and distribution of Zn, Fe, Mn and Cu in roots and shoot of potato clones.The response of shoot Cu concentration to Al was less altered in the Al-tolerant clones than was in Al-sensitive clones. Aluminum tolerance in S. microdontum may be connected with greater levels of Zn, Fe and Mn in the roots.

Crescimento de plântulas de Pfaffia glomerata (Spreng.) Pedersen cultivadas in vitro sob dois níveis de nitrogênio e sacarose, durante seis subculturas sucessivas e aclimatização

The present research was aimed at evaluating the growth of brazilian ginseng (Pfaffia glomerata (Spreng.) Pedersen) in vitro cultured plantlets under two levels of nitrogen and sucrose, during six successive subcultures and acclimatization. Two nutritional treatments were tested: nitrogen at 100% strength of the MS medium + 30g L-1 sucrose; and nitrogen at 50% strength + 45g L-1 sucrose. During six successive subcultures, the explants of 30-day-old plantlets grown under both treatments were transferred, respectively to the next subculture on the same treatment conditions. At 6th subculture, plantlets were transferred to substrate Plantmaxâ Hortalicas and submitted to acclimatization in a growth chamber. Throughout the subcultures, fluctuations in growth response due to nutritional conditions tested were observed. The height of the higher sprout, the average height of sprouts, and the total number of nodal segments per plantlet, respectively for four, four and three subcultures were greater in 100% strength of the MS medium + 30g L-1 sucrose than in 50% strength + 45g L-1 sucrose. On the other hand, dry matter of roots, of shoots and of the whole plant, respectively for two, two and three subcultures, were greater in 50% strength + 45g L-1 sucrose. In conclusion, the increase of sucrose associated with reduction of N level in the culture medium enhanced the biomass production, while the MS at full strength enhanced the growth based in sprout length and number of nodal segments. These differences concerning the biomass production observed during in vitro culture did not persisted in the acclimatization process ex vitro, where MS at full strength give rise greater growth in sprout length and number of leaves per plant.