Physiology of Woody Plants, Edition, T.T. Kozlowski, S.G. Pallardy. Academic Press, San Diego (1996), 411 pp. (ISBN). Price: 69.95 US$, ISBN: 0-12-424162-X

Araticum-de-terra-fria" (Annona emarginata (Schltdl.) H. Rainer) has been consider a good alternative in rootstock production for the main commercial Annonaceae species. Although this species develops in different soil and climate conditions, there is no understanding by the physiological responses of this species at different nutritional levels. Thus, the objective of this study was to evaluate the influence of different ionic strengths on development of vegetative species known as "Araticum-de-terra-fria". It was evaluated in seedlings grown in different ionic strengths (25% I, 50% I, 75% I and 100% I) of the complete nutrient solution Hoagland and Arnon (1950) no 2, for 140 days, the following characteristics: Gas Exchange (CO 2 assimilation rate, stomatal conductance, internal CO 2 concentration, transpiration rate, water use efficiency, Rubisco carboxylation efficiency); Vegetative growth characteristics (diameter, leaf number, dry matter); Physiological Indexes (leaf area ratio, specific leaf area, relative growth rate, net assimilation rate, leaf weight ratio) and Ionic Accumulation (nutrients leaf analysis). Seedlings grown under 50% I showed the highest values of Leaf CO 2 assimilation rate, water use efficiency, carboxylation efficiency, growth, relative growth rate, net assimilation rate and ionic accumulation in the total dry matter. So it is concluded that "Araticum-de-terra-fria" seedlings grown under intermediate nutrient concentrations of complete nutrient solution Hoagland and Arnon (1950) no 2, explored more adequately their physiological potential that justify their adaptation in different nutritional conditions and allow reducing the amount of mineral nutrition of seedlings production. Index terms: Annonaceae, Araticum-de-terra-fria, seedlings, rootstock, macronutrients.

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Gas exchange, phisiological indexes and ionic accumulation in Annona emarginata (Schltdl.) H. Rainer seedlings in nutrients solution

A determinacao do conteudo de clorofilas foliares e uma caracteristica de interesse dos ecofisiologistas e dos
produtores rurais. Com vistas a utilizacao pratica e nas publicacoes cientificas, objetivou-se com o presente trabalho estabelecer, para folhas de seringueira, equacoes capazes de converter para o sistema internacional as unidades arbitrarias que expressam
os teores de clorofila a (Chla), clorofila b (Chlb) e clorofila total (Chltot) obtidos em folhas intactas com uso de clorofilometro portatil. Folhas em diferentes posicoes da planta e diferentes estadios de maturacao, representativas de um grande intervalo de concentracao de pigmentos, foram coletadas e analisadas em campo com uso do ClorofiLOG Falker ®, atraves de quatro
avaliacoes em 45 foliolos medianos. Estes foram posteriormente processados em laboratorio para a obtencao do extrato de pigmentos com uso de dimetilsulfoxido (DMSO) por incubacao em banho-maria, dosagem em espectrofotometro de absorcao
molecular e conversao em teor de pigmentos por unidade de massa fresca, com uso de equacoes convencionais. Os dados foram avaliados quanto ao coeficiente de correlacao de Pearson e testados diferentes modelos de regressao. Para todas as variaveis, o ajuste linear e o mais adequado, com coeficientes de correlacao das equacoes de ajuste (r) de 0,74 para Chlb e 0,88 para Chla e Chltot.

https://revista.ufrr.br/agroambiente/article/download/1737/1335

Validação das unidades arbitrárias do teor de clorofilas obtido em folhas intactas de seringueira.

The harvest timing of peach palm stems for heart-of-palm production is mainly defined by the height and diameter of the stem. Spear leaf parameters could be used in the field to obtain a higher heart-of-palm yield. The aim of this study is to verify if the length and opening of the spear leaf are related to the peach palm heart production. Three harvests were carried out in Campinas (SP), over a period of one year. Before harvest the plants were measured: main stem circumference, height, number of tillers and leaves, length and degree of spear leaf opening. After stem harvest, heart-of-palm production was evaluated. Regardless of the harvest date, the length of the first-rate heart-of-palm was longer when the spear leaf was open. Total mass production of heart-of-palm as a function of spear leaf opening is variable and dependent on weather conditions. When there was a difference in total mass production, this was higher when spear leaf was open. There was no correlation between spear leaf length and total heart-of-palm production. Although there may be an increase in the number of stalks, this had not resulted in a significant effect in terms of mass. The insertion of the spear leaf openness criterion in the determination of the harvest timing may not be worthwhile, since the payment to the producer occurs on the total mass of first-rate heart-of-palm, which may not be higher due to the degree of spear leaf opening.

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Spear leaf in determining the harvest timing of peach palm heart

The determination of foliar chlorophyll content is a characteristic that interests ecophysiologists and rural producers. With consideration for practical uses as well as scientific publications, our present work aims to establish equations, for rubber tree leaves, that can convert arbitrary units of expressing chlorophyll content to the international system. Chlorophyll a (Chla), chlorophyll b (Chlb), and total chlorophyll (Chltot) were obtained from intact leaves using a portable chlorophyll detecting instrument. Leaves from different positions on the plant, at various stages of maturity, and representing a large spectrum of pigment concentrations, were collected and analyzed in the field using the Clorofil OG Falkner ® instrument, through four evaluations in forty-five medium leaflets. At the laboratory, leaflets underwent a process of pigment extraction. They were incubated in a water-bath with dimethylsulfoxide (DMSO), dosed in molecular absorption spectrophotometer, and converted into pigment content per unit of fresh weight using conventional equations. The data were evaluated according to the Pearson correlation coefficient and tested with different regression models. For all variables, the linear fit is the most adequate, with correlation coefficients (r) 0.74 for Chlb and 0.88 for Chla and Chltott.

Validation of arbitrary units of chlorophyll contents obtained in intact leaves of rubber tree.

The close relationship between the chlorophyll-meters readings and the total chlorophyll and nitrogen contents in leaves, has allowed their evaluation both in annual and perennial species. Besides, some physiological events such as the CO2 assimilation have also been estimated by chlorophyll meters. This work was carried out aiming to evaluate the gas exchanges of peach palms as a function of the chlorophyll SPAD-Meter readings. Three year-old peach palms from Yurimaguas, Peru were studied in Ubatuba, SP, Brazil, spaced 2 x 1 m in area under a natural gradient of organic matter which allowed four plots to be considered, according to the peach palms leaves colors, from light yellow to dark green. The SPAD readings and the stomatal frequency of leaflets were evaluated. The photosynthetic photon flux density (PPFD, μmol m-2 s-1), the leaf temperature (Tleaf, oC), the CO2 assimilation (A, μmol m-2 s-1), the stomatal conductance (gs, mol m-2 s-1), the transpiration (E, mmol m-2 s-1) and the intercellular CO2 concentration (Ci, μmol mol-1) were evaluated with a portable infrared gas analyzer (LCA-4, ADC BioScientific Ltd., Great Amwell, U.K.). A linear increase in the CO2 assimilation as a function of the SPAD readings (y = -0.34 + 0.19x, R2 = 0.99), indicates that they can be a rapid and cheap complementary method to evaluate in peach palms some important physiological events, such as CO2 assimilation.

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Gas exchanges in peach palms as a function of the spad chlorophyll meter readings

The Amazonian peach palm is presently the main species of heart-of- palm producer in many Brazilian regions. Here we evaluated the effects of soil water deficit and rewatering on leaf water potential (ψleaf), gas exchange and chlorophyll fluorescence emission in peach palms. Plants were grown in 80 L-plastic pots under greenhouse conditions. Water deficit was imposed by water withdrawing for 13 days, when irrigation was re-established for 8 days more. ψleaf was measured at 5:30 a.m. and 1:30 p.m. Gas exchange measurements were performed at 8:00 a.m. and at 2:00 p.m., after chlorophyll a fluorescence evaluations. The minimum ψleaf value observed at predawn was − 1.6 MPa, when net CO2 assimilation (PN) was zero on the 13th day of water deficit, thus showing mesophytes characteristics. The sharp PN decrease of 94%, 6 days after the beginning of treatments, demonstrated the drastic effect of the soil water deficit. After rewatering, a rapid recuperation of ψleaf was observed, whereas PN, transpiration rate (E) and stomatal conductance (gs) recovered more slowly, reaching values exhibited by the control plants only 7 days after rewatering. The lower maximal quantum yield of photosystem II (PSII) (FV/FM) values in the midday for plants under water deficit indicated dynamic photoinhibition of PS II to excessive PPFD. These results suggest a drought tolerance of peach palm plants, showing stomatal control of water losses and PN limitation, whereas the photosynthetic apparatus was maintained by photoprotection processes.

Valéria Aparecida Modolo

Papers

Gas exchanges in peach palms as a function of the spad chlorophyll meter readings

Photosynthesis and water relations of peach palms (Bactris gasipaes kunth) under soil water deficit.