scholarly journals EFFECT OF SURFACTANTS ON UPTAKE OF GIBBERELLIN A3 BY SOUR CHERRY LEAVES

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1167d-1167
Author(s):  
Moritz Knoche ◽  
Martin J. Bukovac

Gibberellin A3 (GA) applied to virus-infected sour cherry (Prunus cerasus L., `Montmorency') trees inhibits flower initiation and promotes spur formation. However, response to a given dose may vary. Differential foliar absorption has been suggested as a major source of this variation. Therefore, we studied if surfactants would reduce variation in GA absorption. Uptake through the abaxial surface exceeded that through the adaxial surface by about one order of magnitude (adaxial surface 1.1 vs 7.8% in 1988, 0.7 vs 16.6% in 1989). GA uptake was markedly affected by surfactants. Over a 24-hr uptake period, Activator 90 and Ortho X-77 were most effective (abaxial surface 38.3 and 37.4% in 1989), whereas Regulaid did not affect GA uptake. L-77 significantly depressed absorption (abaxial surface 9.1% in 1989). In addition to the level of uptake, surfactants also changed GA absorption kinetics. Penetration increased linearly over a 96-hr time period when Regulaid was included. However, with Ortho X-77, uptake was rapid initially but levelled off within 96 hr. These findings will be discussed in relation to biological response data obtained in the field experiments.

2014 ◽  
Vol 62 (8) ◽  
pp. 647 ◽  
Author(s):  
Ana Paula Lorenzen Voytena ◽  
Bruno Degaspari Minardi ◽  
José Bonomi Barufi ◽  
Marisa Santos ◽  
Áurea Maria Randi

While many ferns have been described as desiccation tolerant (DT), few studies have reported on the mechanisms they use to survive cell desiccation. Among the species belonging to the genus Pleopeltis, P. pleopeltifolia (Raddi) Alston (Polypodiopsida, Polypodiaceae) is a DT species endemic to Brazil. So as to better characterise the mechanisms of desiccation tolerance in ferns, the present study aimed to analyse frond anatomy and physiological changes associated with desiccation and rehydration of P. pleopeltifolia. Fronds are dorsiventral, with uniseriate epidermis. The epidermal cells have various shapes, tending to stretch in the longitudinal direction of the frond. Anticlinal cell walls are sinuous, and periclinal cell walls are convex. Anomocytic stomata are restricted to the abaxial surface. Trichome-type scales are found on both sides of the frond and may play a relevant role in rehydration of this plant when water is available. The mesophyll of the frond consists of palisade parenchyma, tending to a bistratified adaxial surface and spongy parenchyma on abaxial surface. The cuticle on the adaxial surface is conspicuous, ensuring better control of internal water balance. For physiological analyses, sporophytes were subjected to desiccation for 0, 5, 10 and 15 days and rehydration for 1 day. Sporophytes showed a sharp decline in water content when kept without irrigation, reaching 9.6% after 15 days, in addition to wilting and frond rolling. A significant increase in sugar content in fronds was noticeable during desiccation, which may favour a possible osmotic adjustment and vitrification. A notable increase in proline content during rehydration was observed in fronds. During the five initial days of desiccation, the chlorophyll and carotenoid contents decreased abruptly, but after 1 day of rehydration, they had partly recovered. The photosynthetic parameters analysed by fluorescence of chlorophyll a ceased completely after 15 days of desiccation but they had recovered near to pre-desiccation levels after 1 day of rehydration.


2012 ◽  
Vol 20 (2) ◽  
pp. 63-70 ◽  
Author(s):  
Piotr Brzozowski ◽  
Krzysztof Zmarlicki

Abstract Certified organic farm area in Poland increased 8.5 fold during the 2003-2010 time period to 518 thousand ha, which constituted 2.8% of the arable land. The production costs and profitability of the organic fruit production of apples, strawberries, and sour cherries were evaluated and compared to conventional production of those fruits. The research was based on data from thirty-two commercial fruit farms; twenty farms with conventional production, and twelve with organic production. The main problems associated with organic production were the costs of weed control and soil cultivation. The conventional production of apples turned out to be slightly more profitable than the organic production. The organic production of sour cherries was not profitable. In the case of strawberries, it was the opposite - the organic production gave a better financial outcome than the conventional one


1976 ◽  
Vol 16 (79) ◽  
pp. 226 ◽  
Author(s):  
DS Loch ◽  
JM Hopkinson ◽  
BH English

The consequences of defoliation on seed production of stylo (Stylosanthes guyanensis) were examined in field experiments at Walkamin in north Queensland. The practical aim of defoliation is to present a level uncompacted crop canopy to the harvester without a reduction in the quantity of seed carried at harvest ripeness. It was concluded that the latest date at which defoliation is reasonably certain to achieve its objectives is about four weeks before first flower initiation. In north Queensland, this means late February for cvv. Cook and Endeavour and early April for cv. Schofield. The results suggest that development of the population of individual shoots must be synchronized to produce the highest peaks of standing seed; that this is best achieved by ensuring that a closed crop canopy with a ceiling shoot population exists at the time of first flower initiation; and that poorly synchronized shoot development is a consequence of defoliating too late and a cause of reduced seed production.


2014 ◽  
Vol 18 (4) ◽  
pp. 1457-1465 ◽  
Author(s):  
J. Dawidek ◽  
B. Ferencz

Abstract. This study is the first attempt in the literature on the subject of comparing water balance components for floodplain lake basins, depending on the type of a lake connection to the parent river. Research was carried out in the Bug River valley in 2007–2011 water years. Four types of connections were distinguished in the area under study. Simple water balance equation could only be used with regard to the lakes connected to the main river via the upstream crevasses. Detailed and individual water balance equations were developed with reference to the other types of lakes. Water gains and losses varied significantly in the lakes under study. Values of horizontal water balance components (inflow and outflow) of the floodplain lake in Wola Uhruska considerably prevailed over the vertical ones (precipitation and evaporation). Inflow of the Bug River waters was diverse during the time period under study and amounted from 600 000 to 2 200 000 m3 yr−1. Volumes of precipitation and evaporation were rather stable and amounted to approx. 30 000 m3 yr−1. The lowest disparity between horizontal and vertical water balance components was observed in the inter-levee lake. Both upstream inflow of rivers water and outflow from the lake (ranged from 0 in 2008 to 35 000 m3 yr−1 in 2009) were usually an order of magnitude higher than precipitation and evaporation from the lake surface (700–800 m3 yr−1). Study showed that the values and the proportion between aforementioned vertical and horizontal water balance elements were determined by the type of a lake connection to the Bug River. Storage volume showed no relationship to the type of connection, but resulted from individual features of the lakes (location within the valley, precipitation and evaporation volume, difference between water inflow and outflow).


2011 ◽  
Vol 11 (24) ◽  
pp. 13287-13304 ◽  
Author(s):  
T. Röckmann ◽  
M. Brass ◽  
R. Borchers ◽  
A. Engel

Abstract. The isotopic composition of stratospheric methane has been determined on a large suite of air samples from stratospheric balloon flights covering subtropical to polar latitudes and a time period of 16 yr. 154 samples were analyzed for δ13C and 119 samples for δD, increasing the previously published dataset for balloon borne samples by an order of magnitude, and more than doubling the total available stratospheric data (including aircraft samples) published to date. The samples also cover a large range in mixing ratio from tropospheric values near 1800 ppb down to only 250 ppb, and the strong isotope fractionation processes accordingly increase the isotopic composition up to δ13C = −14‰ and δD = +190‰, the largest enrichments observed for atmospheric CH4 so far. When analyzing and comparing kinetic isotope effects (KIEs) derived from single balloon profiles, it is necessary to take into account the residence time in the stratosphere in combination with the observed mixing ratio and isotope trends in the troposphere, and the range of isotope values covered by the individual profile. The isotopic composition of CH4 in the stratosphere is affected by both chemical and dynamical processes. This severely hampers interpretation of the data in terms of the relative fractions of the three important sink mechanisms (reaction with OH, O(1D) and Cl). It is shown that a formal sink partitioning using the measured data severely underestimates the fraction removed by OH, which is likely due to the insensitivity of the measurements to the kinetic fractionation in the lower stratosphere. Full quantitative interpretation of the CH4 isotope data in terms of the three sink reactions requires a global model.


Phytotaxa ◽  
2016 ◽  
Vol 267 (1) ◽  
pp. 77 ◽  
Author(s):  
LAÍCE FERNANDA GOMES DE LIMA ◽  
JOSÉ FERNANDO ANDRADE BAUMGRATZ ◽  
EIMEAR NIC LUGHADHA ◽  
JOÃO UBIRATAN MOREIRA DOS SANTOS

Two new species of Graffenrieda are described from the Amazon rainforest. Graffenrieda maturaca is characterized mainly by its leaves which are dull on the adaxial surface, chartaceous, narrowly elliptic to oblanceolate, and apparently uni-nerved, with only the median acrodromous vein evident. This species has been collected only at Serra de Maturacá, in the state of Amazonas, Brazil. Graffenrieda goldenbergii is distinguished mainly by the pulverulent, whitish, early caducous indumentum of the rachis, pedicel, hypanthium and calyx, by the abaxial surface of the leaves which is moderately lepidote, with trichomes ca. 0.2 mm diam., by the irregularly valvate calyx, and by the membranaceous, costate, not sulcate fruits. This species has been collected in the state of Acre, Brazil, and in the Province and District of Lama in Peru. Both species are illustrated, compared with similar species, and their conservation status is discussed.


1991 ◽  
Vol 117 (1) ◽  
pp. 61-74 ◽  
Author(s):  
D. M. Firman ◽  
P. J. O'Brien ◽  
E. J. Allen

SUMMARYExperiments were conducted in controlled environment cabinets and in the field at Cambridge, UK, in 1987–90 and in Valencia, Spain 1989–90 with several varieties of potato. The initiation of leaf primordia and flowers was recorded in sprouts stored for long periods at 13°C with constant illumination and in sprouts exposed to different photoperiods and periods of cold storage. In field experiments, the effects of a wide range of planting dates, differences in physiological age, the time at which seed tubers were sprouted and of imposing an 8 h photoperiod were investigated.More than 40 leaf primordia were initiated in the sprouts of Home Guard and Arran Comet stored at 13 °C, but, in other varieties, fewer leaves were initiated. Flowers were initiated in the sprouts of some varieties. In field-grown plants, the number of nodes to the first flower differed between varieties and was increased by ageing sprouts before planting. Stems from physiologically old seed of all varieties had more nodes below ground than young seed but the number of aerial leaves to the first flower increased only slightly with increasing physiological age. The number of aerial leaves to the first flower was lower and less variable in Estima than in Maris Piper.Initiation of flowers usually occurred before tuber initiation and within two weeks of emergence but was earlier in some varieties than others. There was little influence of photoperiod on the time to initiation of flowers and tubers in most experiments but, with low levels of radiation, flowering was completely inhibited in the variety Maris Piper.


2017 ◽  
Vol 9 (1) ◽  
pp. 230-236
Author(s):  
Ranbir Singh Rana ◽  
Bhosale Arjun Vaijinath ◽  
Sanjay Kumar ◽  
Ranu Pathania

Field experiments were conducted during rabiseason of 2007-08 and 2008-09 to study the phenology, thermal indices and its subsequent effect on dry matter accumulation of mustard (Brassica juncea L.) varieties viz., RCC-4, Kranti and Varuna grown under varying environmental conditions of Himachal Pradesh. The early sown (10th October) crop varieties took maximum average growing degree days for flower initiation (492±1), 50% flower-ing (682±1), pod initiation (742±1), 90% pod formation (811±4) and maturity (1394±8) which decreased with subse-quent delay in sowing time and recorded lowest under late sown (9th November) crop. The accumulated helio-thermal units and photo-thermal units decreased from 9824 to 7467 oC day hour and 19074 to 15579 oC day hour, respectively. High heat-use efficiency was obtained under late sown condition on 30th October. The heat-use efficiency (HUE) was high at 90% pod formation stage as compared to other stages in all the varieties and sowing dates (except 9th November sowing). The early sown (10th October) crop had maximum calendar days and cumula-tive pan evaporation (158 days and 448.2 mm) followed by normal (20th and 30th October) (153 days and 434 mm) and late (9th November) (138 days and 403.1 mm) sown crop indicating higher water requirement under early sow-ing. The predictive regression models explained 83-85% variation in dry matter yield in three varieties of mustard. The agro climatic indices are important determinants for temperature, radiations and photoperiods behaviors of crop. The accurate predictions of crop phenology are useful inputs for crop simulation modeling and crop management, and used for climate change assessment and simulated adaptations in present scenarios.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1071a-1071
Author(s):  
Ursula K. Schuch ◽  
Leslie H. Fuchigami ◽  
Mike A. Nagzao

Floral initiation in coffee has been shown to be stimulated by short days in young plants, but the inductive stimulus for mature plants is still not clear. Experiments were conducted to determine whether floral initiation in immature and mature plants is promoted by short photoperiods, and delayed by long photoperiods. In a growth chamber study, 18-month-old coffee (Coffea arabica L. cv. Guatemalan) plants exposed to 8 hr photoperiods developed flower buds after 4 weeks, whereas no floral initiation was observed on the plants exposed to 16 hr photoperiods for ten weeks. Trees growing in the field were illuminated with incandescent light from midnight to 3:00 a.m. from July to December 1989. The control plants received no artificial light during the same time period. Night light interruption delayed flower initiation until the end of December on branches that were fully exposed to the light. On control trees, flower buds started to emerge at the beginning of November. These results indicate that in immature and mature coffee plants floral initiation is stimulated by short days, and delayed by long days.


HortScience ◽  
2011 ◽  
Vol 46 (4) ◽  
pp. 596-598 ◽  
Author(s):  
Michael G. Bausher

Vegetative grafting has been proposed as a technique for managing diseases in tomatoes under open-field conditions. Over 2 successive years, we investigated the use of grafting under open-field fresh tomato production and found a serious limitation with current grafting techniques, which resulted in recurring rootstock shoot regrowth (“suckering”) from the rootstock cotyledons when left intact. Left unchecked, the regrowth of tomato rootstocks can envelop the experimental scions, which can impact the growth of field-grown tomatoes. In the Fall of 2007, the cultivars Multifort, Aloha, and TX-301 with ‘FL-47’ scions were grafted by a commercial propagator. These grafted plants were planted in a field experiment and after a time period, the number of rootstock suckers was counted and removed. This process was repeated over five time periods. In 2008, we grafted all of the plants below the rootstock cotyledons. During five different time periods spanning 57 d, bud regrowth from the rootstock occurred in all studied rootstocks in 2007. The difference in the 2 years was dramatic. In the first year, the number of plants with rootstock regrowth was as high as 84.6% in some of the plots for ‘Multifort’, 30.7% for ‘Aloha’, and 15.4% for ‘TX-301’. In the second year, with a different grafting technique, no regrowth from the rootstocks was observed. Even when the rootstock regrowth was removed in 2007, the rootstock sprout growth would reappear from the rootstock. The statistical interaction of the percentage of plants with rootstock regrowth for all recorded dates in 2007 was significant for ‘Multifort’ (Tukey-Fischer P ≤ 0.05) but not ‘Aloha’ or ‘TX-301’. Although the study also contained fumigation treatments, no interaction of soil treatments on root sprouting was observed. Since adopting this method, rootstock regrowth has not been observed in subsequent field experiments for the past 3 years.


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