共查询到20条相似文献，搜索用时 15 毫秒
1.
Pilar Baeza Patricia Sánchez-de-MiguelAna Centeno Pedro JunqueraRubén Linares José Ramón Lissarrague 《Scientia Horticulturae》2007
During the last few years, leaf water potential has been a useful tool in controlling vine water status. However, the time of measurement that could best explain short- and long-term vine responses remains a matter of discussion. The objectives of this work were to study the relationship between vine water status and vine performance and to determine what time of day leaf water potential is best correlated to physiological performance and agronomic vine response. The assay was conducted in Madrid, Spain. Plant material was Cabernet-Sauvignon (Vitis vinifera L.) grafted onto SO4. Three irrigation treatments were established: T1 was non-irrigated, and T2 and T3 were irrigated with a constant fraction of the ETo, k = 0.45 and 0.2, respectively. Vine water status was monitored through predawn, midmorning and noon leaf water potential. Their relationships with net CO2 assimilation rate, vegetative growth rate, yield components and must composition at harvest were studied for 3 consecutive years. Shoot growth rate and net CO2 assimilation rate were better correlated with midmorning and noon leaf water potentials – Ψm and Ψn – than predawn leaf water potential – Ψpd – but all of them were significant. Shoot growth rate was zero for Ψpd = −0.48, Ψm = −1.12 and Ψn = −1.18 MPa. Berry size was better correlated with the water stress integral for predawn (SΨpd) although the water stress integral for midmorning (SΨm) and noon (SΨn) performed quite well. No relationship was found between the water stress integral and TSS, total acidity or pH. Leaf water potential performed as a good parameter for determining both vine water status and agronomic response, but not for evaluating must composition. 相似文献
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Sang-Hyun Lee Jin-Ho Choi Wol-Soo Kim Tae-Ho Han Yong-Seo Park Hirosi Gemma 《Scientia Horticulturae》2006
This study was carried out to investigate the cause of stone cell formation in pear (Pyrus pyrifolia cv. ‘Niitaka’) flesh. Potted plants grown in a glass house were subjected to water stress conditions without irrigation for 30 days from 30 days before full bloom (BFB treatment), full bloom (FB treatment) and 30 days after full bloom (AFB treatment). Control plants were drip-irrigated daily maintaining a soil matrix potential around −40 ± 5 kPa. The formation of stone cells in pear flesh increased in the FB treatment and AFB treatment plants and this tendency was sustained until the harvest season. Root activity was investigated 60 days after full bloom (DAFB) and the triphenyltetrazolium chloride (TTC) reduction potential, the formazan content and leaf water potential were investigated 30, 45, and 60 DAFB. Root activity decreased progressively due to the effect of water stress. Also, the Ca content in leaf and flesh was lower. The peroxidase activity was high in the flesh at the early stages of fruit growth and decreased at the late stages of fruit growth, and then a higher increase of peroxidase activity was observed in water-stressed fruit. The reduction in calcium content of leaf and fruit in plants under water stress may be related to the reduction of root activity and leaf water potential. The increase in peroxidase activity under water stress may be due to limited calcium absorption. Higher peroxidase activity may induce the accumulation of lignin in the cell wall and promote the formation of stone cells in pear flesh. We conclude that water stress condition during the early stages of fruit growth is one of several factors that determine the formation of stone cells in pear flesh. 相似文献
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A field experiment was conducted during 2005 and 2006 growing seasons at Ras Munif (32°22′N, 35°45′E), Ajloun, Jordan, to evaluate different pollination treatments and their effects on fruit set and quality of loquat fruit grown under Mediterranean conditions. Open, supplemental, rain, and covered pollination treatments were imposed on the selected trees. Results showed that under supplemental and open-pollination, extremely higher fruit set was obtained compared with rain and covered treatments. In spite of a heavy crop load, fruits obtained under open and supplemental pollination were also heavier and larger, this could be partly due to a significant increase in seeds and flesh weight. Sugar content was good for both open and supplemental pollination. Wind plays little or no role in loquat pollination process. Loquat flowers attracted very limited number of bee visitors, A. mellifera, Anthophora albigena and Xylocopa violocea of family Apidae and Halictus quadricinctus of family Halictidae were recorded the only loquat flower visitors. They showed a variation in their visiting time but loquat flowers attracted the highest rate and number during the mid of the day. 相似文献
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This study evaluates the effect of gibberellic acid (GA3) in inducing parthenocarpy in ‘Algerie’ loquat, as well as the optimum treatment conditions and associated techniques, hand thinning and ringing, to produce seedless fruit with high enough quality for fresh consumption. GA3 applied in the course of the phenological growth stages 504–508 of the BBCH-scale produced seedless fruits, with the magnitude of the response depending on the concentration applied and number of treatments. Percentage of panicles bearing seedless fruitlets significantly increased with increasing GA3 concentrations up to 100 mg l−1 and significantly and positively correlated with the number of treatments applied. Trees treated three times with 100 mg l−1 developed more than 90% of panicles bearing almost 7 seedless fruits per panicle, which were smaller in size, drier and slightly acid but similar in TSS concentration and skin colour than seeded fruits from untreated trees. Fruit thinning to 3 fruits per panicle did not increase seedless fruit size, but ringing performed at the onset of cell enlargement stage, growth stage 702 of the BBCH-scale, significantly increased fruit size by 12–15%, depending on the year. Trees treated three times with 100 mg l−1 of GA3 and ringed produced 26 kg, on average, of seeded fruit of suitable commercial quality. 相似文献
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Iván García Tejero Víctor Hugo Durán ZuazoJuan Antonio Jiménez Bocanegra José Luis Muriel Fernández 《Scientia Horticulturae》2011
Water efficiency is a key concept to solve water-shortage problems in semiarid areas. Deficit irrigation (DI) in many crops has frequently proved to be an efficient tool to optimise water-use efficiency. Three different DI strategies were studied for commercial orchards of mature sweet orange (Citrus sinensis L. Osbeck, cv. Salustiana and cv. Navelina) from 2006 to 2008: sustained deficit irrigation (SDI), regulated deficit irrigation (RDI), and low-frequency deficit irrigation (LFDI) all defined physiologically with stem-water potential thresholds. The experimental research plots were located in the Guadalquivir river basin, SW Spain. The effects of DI treatments on the fruit yield and on the crop-water status, by the integrated stem-water potential (Ψint) were analysed. Also, the benefits of DI in terms of agricultural water-use efficiency (WUEagr) and financial water-use efficiency (WUEf) were estimated for each irrigation strategy. Different relationships were estimated between these parameters and irrigation and total water applied, in order to establish the best irrigation strategy for different irrigation regimes. Yield and Ψint showed significant differences consistent with the water amounts applied, although the crop response was influenced by other parameters such as crop variety and irrigation strategy. In this sense, treatments with similar irrigation rates and Ψint resulted in different yield values, evidencing the importance of these factors. Regarding the crop variety, the results showed that cv. Salustiana responded better than cv. Navelina to DI, from the physiological and agricultural perspectives. In terms of water savings, the RDI and LFDI reduced water use by between 1000 and 1250 m3 ha−1, respectively, with similar yields in comparison to the fully irrigated treatment, significantly improving the WUE. Consequently, the WUEf, and WUEagr were more strongly affected by deficit-irrigation strategy rather than the total water supplied. Thus, the amount of irrigation water would have a relative importance but other variables such as the irrigation strategy, would decidedly influence prudent water management in semiarid areas. 相似文献
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Chiraz Charfi Masmoudi Mouna Mezghani Ayachi Mohamed Gouia Foued Laabidi Saloua Ben Reguaya Abderrazzek Oueled Amor Mohamed Bousnina 《Scientia Horticulturae》2010
The experiment was carried out at the Experimental Field ‘Taoues’, southern Tunisia (34°N, 10°E) to examine the effect of irrigation schedules on water relations for young olive trees, cultivars Chétoui, Chemlali, Coratina, Picholine and Manzanille. Plants were cultivated at 7 m × 7 m spacing and drip irrigated from April to September. Irrigation amounts (IA) of 20%ETc, 50%ETc and 100%ETc were applied, where ETc is the FAO crop evapotranspiration. The effect of IA on midday leaf water potential (Ψleaf), stomatal resistance (Rs) and conductance (gs), soil (Hv) and relative leaf (RWC) water contents was studied. Results showed that a further increase in IA was not systematically followed by an increase of water potential, production and WUE values. Some controversial responses were observed following to a variety with large seasonal variations. At the beginning of the growing season, differences between treatments were not very important because soil water content was still high enough to prevent important changes in Ψleaf values. The most stressed trees showed potentials of −1.53 MPa for Picholine cv. and ranging between −2.30 MPa and −2.10 MPa for the other varieties depending on IA. The less stressed trees provided potentials of −0.97 MPa for Picholine cv. and varying between −1.63 MPa and −2.13 MPa for cultivars Coratina, Manzanille, Chétoui and Chemlali. Then, as the season progresses, and when IA was increased from 20%ETc to 50%ETc, Ψleaf values decreased significantly for cultivars Chemlali (−3.05 MPa), Coratina (−3.75 MPa), Manzanille (−3.0 MPa) and Chétoui (−3.5 MPa). At 100%ETc, Manzanille and Picholine cultivars show better water status with respective potentials of −2.7 MPa and −2.6 MPa. Stomatal resistance monitoring showed maximums at midday for all cultivars with pick value of 4.45 s/cm recorded for Chétoui cultivar irrigated at 50% ETc. The most important variations were recorded for cultivar Chemlali which seem to be the ablest to regulate stomata aperture. Close coordination between Ψleaf and gs and Ψleaf and RWC measurements was found. But, the response varied following to treatment. At low irrigation levels (20%ETc and 50%ETc), gs was found to be linearly and positively correlated to Ψleaf. It increased linearly and positively with increasing values of Ψleaf (r of 0.84 and 0.96, respectively). At 100%ETc, Ψleaf is found to be correlated to gs following to a polynomial function with an optimum gs value of 450 mmol/m2/s and Ψleaf of about −2.5 MPa. 相似文献
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The fruit shape in muskmelon (Cucumis melo L.) was classified as flat, round or oblong on the basis of shape index, and inheritance of these shapes was found to be complicated. Stripes on the rind of the fruit were governed by a single recessive gene st and their inheritance was independent of the nature of the rind whether netted or smooth.For netting on the fruit rind 2 genes were found. N gene controlled netting, its allele n smoothness. S gene suppressed netting when present in homozygous condition. N was epistatic over S and so was n over s. In the absence of N, SS caused smoothness and Ss caused netting. The smooth parents ‘Lucknow Safeda’, ‘Sl. 445’ and ‘Durgapura Madhu’ were found to be different from ‘Persiiski-5’ with respect to genes for smoothness.Inheritance of flesh pigments in green × white crosses showed that green flesh was conditioned by a recessive gene. However, in orange × green, green × orange and orange × white, flesh colour inheritance was complex.A possibility of maternal inheritance of pigments and an interaction between nuclear and extra-nuclear genes was suggested. Probably different genes were controlling chlorophyll and carotenoid pigments through separate biochemical pathways. 相似文献
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Two apple (Malus × domestica Borkh.) orchards, a conventional and an organic one, were compared in terms of plant growth, marketable fruit quality attributes (fruit weight, shape, color, phenolic compound concentration, nutrients) and yield. The two orchards were located nearby, in order to exclude possible pedoclimatic influences on the measured variables. The two management systems resulted in similar new season's shoot growth and similar fruit quality attributes, in terms of total soluble solids, juice pH, titratable acidity and color indexes, while the conventionally grown trees produced almost twice the yield of the organically managed ones. The flesh plus peel portion of the conventionally produced fruits exhibited higher total flavonoid and o-diphenols concentration, while the flesh portion presented higher flavonoid concentration. Nitrogen concentration was higher in all portions of conventionally grown fruits, while potassium, calcium, sodium and manganese concentrations were higher in the flesh portion of organically produced fruits. Significant differences were observed between management systems concerning fruit nutrient ratios, but their values were within the desired ranges, under both conventional and organic management systems. 相似文献
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In order to screen almond genotypes for drought tolerance, three different irrigation levels including moderate and severe stress (Ψs = −1.2 and −1.8 MPa respectively) and a control treatment (Ψs = −0.33 MPa) were applied for five weeks to six different cultivated almond seedlings. A factorial experiment was conducted with a RCBD which included 3 irrigations factors, 6 genotype factors and 3 replications. Seeds were prepared from controlled pollination of the bagged trees (after emasculation and flower isolation using isolator packets in the previous year). Genotypes included: homozygote sweet (Butte), heterozygote sweet (SH12, SH18, SH21 and White) and homozygote Bitter (Bitter Genotype). Leaf and root morphological and physiological traits including; midday relative water content, midday leaf (xylem) water potential, shoot dry weight and growth, total leaf area, leaf size, total leaf dry weight, specific leaf area, leaf greenness (SPAD), stomatal size and density, root and leaf nitrogen content and chlorophyll fluorescence were measured throughout the study. Results showed the six genotypes had different reactions to water stress but all genotypes showed an ability to tolerate the moderate and severe stresses and they showed different degrees of response time to drought stress. Almond seedling leaves could tolerate Ψw between −3 and −4 MPa in short periods. Water availability did not significantly affect stomatal density and size of young almond plants. The analysis of leaf anatomical traits and water relations showed the different strategies for almond genotypes under water stress conditions. Although almond seedlings even in severe stress kept their leaves, they showed a reduction in size to compensate for the stress effects. All genotypes managed to recover from moderate stress so Ψw = −1.2 could be tolerated well by almond seedlings but Ψw = −1.8 limited young plant growth. Leaf greenness, leaf size, shoot growth, shoot DW, TLDW and stomatal density were not good markers for drought resistance in almond seedlings. Root DW/LA, lower stomatal size and lower SLA might be related to drought resistance in cultivated almonds. Butte had the least resistance and White showed better performance during water stress while other genotypes were intermediate. Bitter seedlings showed no superiority in comparison with other genotypes under water stress conditions except for better germination and greater root DW which might make them suitable as rootstocks under irrigation conditions. 相似文献
11.
Francilene Gracieli Kunradi Vieira Graciele Da Silva Campelo Borges Cristiane Copetti Patricia Faria Di Pietro Eduardo da Costa Nunes Roseane Fett 《Scientia Horticulturae》2011
The total phenolic, flavanol, monomeric anthocyanin contents and the antioxidant activity of flesh and peel of 11 apple cultivars from Brazil were investigated. Concentrations of the parameters measured differed significantly among the apple cultivars and were highest in the peel compared to the flesh. Total phenolic content (mg GAE/100 g fresh matter) ranged from 128.3 (Golden Delicious) to 212.0 (Epagri-F5P283) in the flesh and 304.6 (Golden Delicious) to 712.6 (Catarina) in the peel. Total flavanol content (mg CAE/100 g fm) varied from 11.7 (Epagri-SJ11) to 28.2 (Epagri-F43P23) and from 32.4 (Epagri-SJ11) to 147.7 (Catarina) in the flesh and peel, respectively. COOP-24 peel had the highest total anthocyanin content. The Epagri-F5P283 and Epagri-F43P23 flesh and Catarina peel had the highest antioxidant activity while Golden Delicious flesh and peel had the lowest. The total phenolic content and antioxidant activity were significantly correlated in both flesh (R2 = 0.717) and peel (R2 = 0.716). The contribution of phenolics to the antioxidant activity in peel suggests that their removal may induce a significant loss of antioxidants. 相似文献
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《Scientia Horticulturae》2005,104(2):221-236
This study was to assess selection criteria for salt tolerance in halophytic seashore paspalum (Paspalum vaginatum Swartz) ecotypes, and to determine influence of salinity on water status. Nine seashore paspalums exhibiting the widest range of salinity tolerance were grown in a greenhouse using nutrient/sand culture. Comparative salinity tolerance was determined by measuring shoot, root, and verdure dry weights at six salinity levels (1.2–49.7 dS m−1). Threshold ECw (electrical conductivity of water), ECw50%, ECw25%, and leaf firing (LF50) were also measured. Total water potential (Ψw), solute potential (Ψs), turgor pressure (Ψp), and relative water content (RWC) were determined as measures of water status across salinity levels. Based on the number of times in the top (best) statistical category for growth measurements, SI 93-2 and HI 101 were the most salt-tolerant ecotypes, while Adalayd was least tolerant. Results indicated that comprehensive assessment of salt tolerance using different tissues across salinity levels up to ECw50 were desirable and repeatable in halophytic seashore paspalums. The criteria ECw50%, ECw25%, and LF50 were also useful in ranking of salt tolerance, but threshold ECw was not reliable in halophytic turfgrass. Shoot Ψw and Ψs decreased continuously in all ecotypes as salinity increased. Trends in shoot growth of salt-tolerant SI 93-2 and HI 101 and least tolerant Adalayd paralleled responses of shoot Ψp with the more tolerant ecotypes maintaining more favorable Ψp and growth. Among parameters of water relations, shoot Ψw and Ψp were found to have the largest effects, which accounted for 82% and 22% of variations of shoot and root growth of seashore paspalums, respectively. 相似文献
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Carmina Reig Vittorio Farina Giorgio Volpe Carlos Mesejo Amparo Martínez-Fuentes Francesca Barone Francesco Calabrese Manuel Agustí 《Scientia Horticulturae》2011
The application of gibberellic acid (GA3) to the whole loquat tree from mid-May to early June and from early August to the onset of flowering, significantly reduced the number of premature flowering shoots per current shoot and per m3 of canopy, and so reduced the total number of panicles per m3 of canopy. The number of vegetative shoots per m3 of canopy was also significantly reduced by applying GA3. The response depended on the concentration applied and produced optimal results at 50 mg l−1. Differences in the number of flowers per panicle and leaves per shoot were not significantly modified by the treatment. Nevertheless, GA3 applied directly to the developing apex near to flower differentiation reduced the number of flowers per panicle by 25–35% and without modifying the morphological characteristics of the panicle. Results suggest that less sprouting of lateral buds was largely responsible for the reduction in flowering intensity caused by GA3. Best treatments reduced thinning costs (60%, approximately) of premature flowering shoots, slightly increased fruit diameter and significantly improved fruit colour and juice quality, thus advancing harvest date. 相似文献
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Water spray as a potential thinning agent for date palm flowers (Phoenix dactylifera L.) c.v. ‘Lulu’
Flower or fruit thinning is a critical cultural practice in the date palm production chain that affects fruit development, quality and yield and regulates tree yearly bearing. Development of a save and economic thinning agent for date palm is critically required especially under harsh conditions. During 2004 and 2005 seasons, water spray for 3 min was applied at different times following mechanical pollination on ‘Lulu’ date palm cultivar growing under Al-Ain oasis conditions. The results showed that water spray following pollination generally decreased fruit set percentage to different extent depending of the time of application. In this respect, the most effective treatment was water spray after 4 h following pollination. This treatment significantly decreased fruit set percentage (48%) compared to the control (79%), as the mean of both seasons. However, the other treatments including water spray 1 h before pollination also decreased fruit set percentage but to a lesser extent. Fruit quality characteristics especially fruit and flesh weight, length and diameter were significantly increased by water spray treatments during the 2004 season, in contrast to the 2005 season. Thinning with water significantly decreased both bunch weight and total yield per tree at the Tamr stage especially when applied after 4 h following pollination. To the best of our knowledge, this is a pioneer study investigating the role of water as a potential thinning agent for date palm flowers. The use of water spray as a save and economic thinner needs, however, more research work to justify the time following pollination and duration of application which may vary upon cultivar, method of pollination and district. 相似文献
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Cucumber fruits (Cucumis sativus L., cv. Trópico F1) grown on perlite substrate and NFT (Nutrient Film Technique) were harvested during two seasons (winter and spring) to monitor the effects of climatic conditions and hydroponic growth systems on fruit quality at harvest. The best fruit quality at harvest, as measured by lightness and hue angle parameters, was obtained during the 3 weeks following the first winter picking. When values of a parameter of preharvest climate value called G* were lower than 0.4 MJ m−2 °C day−1 interval−1, the cucumber achieved its optimum quality at harvest, as measured by the dark green color of the skin. NFT-grown fruits showed darker and greener skin color (higher hue angle and lower lightness) compared with perlite-grown fruit, irrespective of the season considered. During the winter season, the plant transpiration rate was 30% higher in perlite than in NFT culture, which correlates with higher differences in G* and 40% additional yield in perlite. However, in spring G* was not sensitive enough to discriminate between the two hydroponic systems. In general, fruit quality at harvest in spring was lower than during the winter, due to flesh whitening, higher longitudinal and equatorial calibers, and slightly higher pH, as well as worse epidermal color coordinates (ranging from the dark and dull green color typical of winter fruit to light and a vivid green-yellow color). During the spring season, NFT-grown fruit were less acid than perlite-grown fruit with no apparent correlation with the climatic conditions or fruit nutrition. 相似文献
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Berry weight (BW) and sugar concentration (SC) are relevant indices in viticulture since they can be easily measured and, when considered together, give a relatively fair estimation of grape quality. This work aims to evaluate the influence of water availability, leaf area and fruit load on BW and SC, estimating the relative importance of these factors. Leaf area (LA), berry number (BN), yield (YLD), water potential in summer (ψpd-s), BW and SC were measured in 16 and 17 ‘Tempranillo’ vineyards in 1999 and 2000, respectively. In all the vineyards, according to local practices, the irrigation amount decreased as summer progressed. The study vineyards comprised a broad range of situations concerning leaf area, fruit load and water status in summer. Average leaf water potential in summer and LA/BN ratio, when considered together, estimated properly BW (R2 = 0.91; P < 0.001) and, in a similar way, ψpd-s and LA/YLD ratio estimated SC (R2 = 0.74; P < 0.001). The relative weight of ψpd-s in both relationships was much higher than that of any of the LA:fruit ratios, showing that, under semiarid conditions, water availability plays the main role in regulation of berry growth and sugar accumulation and, therefore, the highest attention should be paid in these areas to irrigation management, seeking the degree of stress that allows optimizing the combination of yield and berry quality in each situation. 相似文献
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Despite problems of low fruit set, small fruit size and alternate bearing, the Hass cultivar dominates commercial avocado production worldwide. To increase yield and fruit size, gibberellic acid (GA3) (25 mg L−1) was applied at different stages of ‘Hass’ avocado tree phenology: (i) mid–late April (flower abscission), end of June–beginning of July (fruit abscission and beginning of the exponential phase of fruit growth), and mid-January (beginning of pre-harvest fruit drop); (ii) end of June–beginning of July; and (iii) mid-September (near the end of the major fruit abscission period; period of exponential fruit growth). In both years of the research, applications of GA3 in April and June–July were within the periods of intense flower and fruit abscission, respectively; fruit abscission was low in September and January. Maximum air temperature was not related to flower or fruit abscission. In the on-crop year (391 fruit per untreated control tree), a single application of GA3 at the end of June–beginning of July significantly increased total yield (kilograms only) and yield of commercially valuable fruit (178–325 g/fruit) (as kilograms and number per tree) compared with the control (P < 0.0001). GA3 applied in September increased total yield (kilograms only) and yield of commercially valuable fruit (kilograms and number per tree) to values intermediate to and not significantly different from all other treatments, except trees receiving multiple applications of GA3. This treatment reduced total yield and yield of commercially valuable fruit (kilograms and number per tree) relative to all treatments (P ≤ 0.0002). In contrast, during the off-crop year (32 fruit per control tree), no GA3 treatment had a significant effect on yield or fruit size compared with the control and all other GA3 treatments. For ‘Hass’ avocado, there was no negative effect from applying GA3 at the end of June–beginning of July in both the off- and on-crop years; 2-year cumulative total yield and yield of commercially valuable fruit were increased by 27 kg (128 fruit) and 22 kg (101 fruit) per tree, respectively, above the yield of untreated control trees (P < 0.0001). 相似文献