A preliminary genetic linkage map of chrysanthemum (Chrysanthemum morifolium) cultivars using RAPD,ISSR and AFLP markers

A genetic linkage map of chrysanthemum (Chrysanthemum morifolium) was constructed by genotyping 142 F₁ progeny of the bi-parental cross ‘Yuhualuoying’ × ‘Aoyunhanxiao’ with a combination of RAPD, ISSR and AFLP markers in a double pseudo-testcross mapping strategy. A total of 567 polymorphic markers, including 153 RAPDs, 61 ISSRs and 353 AFLPs, were used in linkage mapping. 336 of 567 (60%) markers were grouped on the two parental maps, leaving 231 (40%) markers unlinked. In the ‘Yuhualuoying’ linkage map, 210 markers including 116 testcross and 94 intercross markers were placed in 12 major and 32 minor (8 triplets and 24 doublets) linkage groups, covering 1034 cM with an average map distance of 6.2 cM between adjacent markers. In ‘Aoyunhanxiao’ linkage map, 190 markers consisting of 113 testcross and 77 intercross markers were resolved into 9 major and 24 minor linkage groups, with genome coverage of 1095 cM and a mean inter-marker separation of 6.9 cM between adjacent markers. Six pairs of homologous linkage groups were established on the basis of 64 intercross markers shared by the two parental maps. The maps lay a foundation for further quantitative traits loci (QTL) mapping and marker-assisted breeding of chrysanthemum.     

Anther wall development,microsporogenesis and microgametogenesis in male fertile and sterile chrysanthemum (Chrysanthemum morifolium Ramat., Asteraceae)

Anther wall development, microsporogenesis and microgametogenesis were compared between a normal male fertile chrysanthemum cultivar ‘NJAU04-29-2’ and the two male sterile selections ‘rm20-11’ (anther indehiscent) and ‘NJAU05-52-2’ (anther aborted). In both of the two male sterile types, the tapetum enlarged abnormally and showed signs of disorganization of walls at the onset of meiosis, the pollen was aborted, the anthers appeared shrunken, and the anther vascular bundle and connective tissue were degenerated by anthesis. In ‘rm20-11’, the two smaller pollen sacs began to degenerate at the microsporogenesis stage, so that only one or two microsporangia developed, while in ‘NJAU05-52-2’, only one or two microsporangia were formed following the archesporial cell stage, and most of the microspore mother cells degenerated during the course of meiosis.     

The effects of some chemical treatments on leaf water conductance of cut,flowering stems of Chrysanthemum morifolium

The leaf water conductance of cut, flowering stems of Chrysanthemum morifolium was measured by diffusion porometry. The stems were placed in solutions of chemicals which have commonly been used in flower preservatives, or which might be expected to affect the physiology of the leaves.In the environmental conditions of our experiments (18° C; 0.8 kPa; 5 W m^?2 visible radiation for 8 h) sucrose (6 %) and abscisic acid (0.001 %) lowered leaf water conductance. Silver nitrate (0.003 %) or 8-hydroxyquinoline sulphate (0.02 %) either had no effect or increased leaf water conductance. We conclude that the latter two substances increase the vase life of cut flowers by affecting the physiology and pathology of the stem rather than the stomatal physiology of the leaf. The leaves of stems standing in high concentrations of sucrose accumulated sucrose and were frequently damaged as a result.The results are discussed with regard to the water relations of the cut flower and the possible use of anti-transpirants.     

Effects of Prohexadione Calcium on growth and gibberellins contents of Chrysanthemum morifolium R. cv Monalisa White

The effect of Prohexadione Calcium (Pro-Ca) and daminozide was observed on the growth characteristics and endogenous gibberellin contents of Chrysanthemum morifolium R. cv Monalisa White. Three concentrations viz. 100, 200 and 400 ppm of Pro-Ca and a single concentration of daminozide (800 ppm) were applied three times with 7 days interval on three weeks old plant under greenhouse condition. Pro-Ca suppressed the plant length up to 30.7% while daminozide inhibited up to 27.12% at optimum concentration. The chlorophyll contents and stem diameter were higher than control, while the fresh weight and flower number insignificantly reduced with such treatments. Gibberellin (GA) analysis showed that Pro-Ca and daminozide application significantly lowered bioactive GA₁ content, although the amount of its immediate precursor GA₂₀ was fractionally higher. Bioactive GA₄ content was slightly higher than the control while significant difference in GA₉ was found between the plants treated with Pro-Ca and daminozide. Current study showed that both early C13 hydroxylation and non-C13 hydroxylation pathways of GA biosynthesis are operational in C. morifolium.     

Comparative effects of deficit irrigation (DI) and partial rootzone drying (PRD) on soil water distribution,water use,growth and yield in greenhouse grown hot pepper

This study was conducted to compare two water-saving practices, deficit irrigation (DI) and partial rootzone drying (PRD), and examine how they affected soil water distribution, water use, growth and yield of greenhouse grown hot pepper compared to commercial irrigation (CI). Control (CI) in which irrigation water was applied to both sides of the system when soil water content was lower by 80% of field capacity; deficit irrigation (DI50, DI75) in which 50% and 75% irrigation water of CI supplied to both sides of the root system; 1PRD with half of the root system exposed to soil drying and other half kept well-watered with 50% irrigation water of CI, and 2PRD with 50% irrigation water of CI supplied, half to fixed side of the root system. The results showed mean soil volumetric water content of DI75, DI50, 1PRD and 2PRD were lower by 21.06%, 28.32%, 24.48% and 34.76%, respectively than that of CI after starting the experiment. Water consumption showed some significant effect of irrigation treatments during the growing period of drought stress application, and therefore decreased in DI75, DI50, 1PRD and 2PRD to a level around 75% and 50% of CI. All the DI and PRD treatments resulted in a reduction of total dry mass of 7.29–44.10%, shoot biomass of 24.97–47.72% compared to CI, but an increase in the root–shoot ratio of 12.50–35.42% compared to the control and with significant differences between 2PRD, 1PRD, DI50 and CI. The yield of 1PRD was significantly reduced by 23.98% compared to CI (19,566 kg hm⁻²) over a period of 109 days after transplanting. However, the 1PRD treatment had 17.21% and 24.54% additional yield over the DI50 and 2PRD treatments and had 52.05% higher irrigation water use efficiency (IWUE) than CI treatment. At harvest, although there was a significant difference recorded as single fruit weight and single fruit volume were reduced under the DI and PRD treatments, total soluble solids concentration of fruit harvested under the water-deficit treatments were higher compared to CI. Stomatal conductance measured in fresh leaf was the lowest under 1PRD treatment relative to CI and other treatments. The low stomatal conductance of fresh-leaf issue observed in the work supported the root signaling mechanism reported earlier in plants having undergone partial root drying cycles.     

Effect of day and night temperatures during short photoperiods on growth and flowering of Chrysanthemum morifolium Ramat

The effect of day and night temperatures of 10, 14 and 18°C on growth and flowering under short days was studied with six cultivais of chrysanthemum. A high day temperature resulted in earlier flowering and taller stems, but did not influence flower number and final total fresh weight, and only slightly influenced the distribution of fresh matter over stem, leaves and flowers. A high night temperature resulted in earlier flowering, more flowers and reduced stem and leaf weight. It did not affect leaf number and it influenced height and total fresh weight only slightly. Except for height, the day temperature acted independently from the night temperature. The cultivars responded similarly, except for two cultivars which generally did not flower at 10/10,10/14 and 14/10°C D/N. One cul-tivar produced more flowers at 14 than at 18°C.     

Effect of NaCl salinity in the genotypic variation of cowpea (Vigna unguiculata) during early vegetative growth

Twenty-five genotypes of cowpea (Vigna unguiculata L. Walp.) were tested for salt-tolerance at the vegetative growth stage in pot in the greenhouse experiments at salinity levels of 0, 85, and 170 mM NaCl. Plant survival was the main criterion for classifying genotypes. Other criteria included the ion concentration (Na⁺ and Cl⁻) in root and shoot and biomass accumulation. Four local accessions (‘Paceño’, ‘Tardón’, ‘Sonorense’, and ‘Cuarenteño’), three accessions from California (‘CB46’, ‘CB27’, and ‘CB3’), and one accession from the International Institute of Tropical Agriculture (IITA) (‘IT82D-889’) survived at concentrations of both 85 and 170 mM NaCl and were classified as salt-tolerant, while ‘IT96D-666’, ‘IT89KD-288’, and ‘IT93K-734’ from IITA were classified as salt-sensitive. One local accession (‘Sesenteño’), three accessions from IITA (‘PEPH-V Wes-85’, ‘IT86D-719’, and ‘IT95K-1090-12’), and one accession from California (‘CB5’) were classified as moderately salt-tolerant. Eight accessions from IITA (‘IT96D-733’, ‘IT90K-277-2’, ‘IT91K-93-10’, ‘IT91K-118-20’, ‘IT90K-284-2’, ‘IT95K-1088-4’, ‘IT89KD-391’, and ‘IT94K-437-1’) and one from California (‘CB88’) were classified as moderately salt-sensitive. Biomass was affected by both 85 and 170 mM NaCl in all groups of genotypes, however, salt-tolerant and moderately salt-tolerant genotypes showed higher biomass than genotypes classified as moderately salt-sensitive and salt-sensitive. In all genotypes Cl⁻ concentration was higher in shoots than roots and increased as salinity increased. Similarly Na⁺ concentration increased with increasing salinity. However, in salt-tolerant and moderately salt-tolerant genotypes, Na⁺ concentration was more in roots than shoots, while in moderately salt-sensitive and salt-sensitive genotypes, Na⁺ was higher in shoots than roots.     

Photosynthetic and growth responses of juvenile Chinese kale (Brassica oleracea var. alboglabra) and Caisin (Brassica rapa subsp. parachinensis) to waterlogging and water deficit

Chinese kale (Brassica oleracea var. alboglabra) and Caisin (Brassica rapa subsp. parachinensis) are leafy vegetable crops grown in south-east Asian countries where rainfall varies dramatically from excess to deficit within and between seasons. We investigated the physiological and growth responses of these plants to waterlogging and water deficit in a controlled experiment in a glasshouse. Juvenile plants were subjected to waterlogging or water deficit for 19 days in case of Chinese kale and 14 days in case of Caisin and compared with well-watered controls. Caisin tolerated waterlogging better than Chinese kale because it produced hypocotyl roots and gas spaces developed at the stem base. In Chinese kale, waterlogging reduced plant fresh weight (90%), leaf area (86%), dry weight (80%) and leaf number (38%). In contrast, waterlogging had no impact on leaf number in Caisin and reduced plant fresh and dry weights and leaf area by 60–70%. Water deficit reduced leaf area, fresh weight and dry weight of both species by more than half. Leaf number in Chinese kale was reduced by 38% but no effect occurred in Caisin. Water deficit increased the concentration of nitrogen in the leaf dry matter by more than 60% in both species and the leaf colour of water deficient plants was dark green compared with the leaf colour of well-watered plants. Soil water deficit delayed flowering of Caisin while waterlogging accelerated it. Thickening and whitening of the cuticle on the leaves of Chinese kale probably increased its ability to retain water under drought while Caisin adjusted osmotically and Chinese kale did not. Waterlogging and water deficit had strong effects on leaf gas exchange of both Brassica species. Water deficit closed the stomata in both species and this was associated with a leaf water content of 9 g g⁻¹ DW. In contrast, waterlogging reduced conductance from 1.0 to 0.1 mol H₂O m⁻² s⁻¹ in direct proportion to changes in leaf water content, which fell from 11 to 5 g g⁻¹ DW. This separation of the effects of water deficit and waterlogging on conductance was reflected in transpiration, internal CO₂ concentration and net photosynthesis. In conclusion, Chinese kale and Caisin showed rather different adaptations in response to waterlogging and water deficit. Caisin was more tolerant of waterlogging than Chinese kale and also showed evidence of tolerance of drought. There is genetic variation to waterlogging within the Brassica genus among the leafy vegetables that could be used for cultivar improvement.     

Effect of day and night temperatures during long photoperiods on the vegetative growth and flowering of Chrysanthemum morifolium Ramat

The influence of day and night temperatures in the range of 10–17°C on the vegetative growth under long days of 17 year-round cultivars of chrysanthemum was studied. The after-effect of the temperature regime on the time of flowering at 17°C under short days was also recorded.A decrease of the day or night temperature reduced growth, but the effect of the day temperature was much stronger than that of the night temperature. The temperature during the vegetative period had hardly any effect on the time of flowering at 17°C.The consequences for production and breeding are discussed.     

Effect of soil water stress on the development of stone cells in pear (Pyrus pyrifolia cv. ‘Niitaka’) flesh

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.     

Effects of water deficit on the vegetative response,yield and oil quality of olive trees (Olea europaea L., cv Coratina) grown under intensive cultivation

An experiment was carried out in a young high-density olive grove (556 plants ha⁻¹—Olea europaea L., cv Coratina) located in Southern Italy to evaluate the effect of different soil water availability on the vegetative and productive performances of olive trees also looking into the quality of the resulting oils. Trials were carried out over a 3-year period on trees subjected to irrigation and grown under rainfed conditions. Vegetative tree response, as shoot elongation and trunk diameter, was evaluated. Yield per plant, fruit characteristics, oil quality indices (free fatty acid content, peroxide value, UV adsorption at 232 and 270 nm, total phenols, α-tocopherol content) were determined for both irrigated and non-irrigated treatments in the ‘on’ years 1997 and 1999 (6th and 8th year after planting, respectively).     

梨园套种平菇对土壤生物活性及果实品质的影响

【目的】为探明套种平菇对梨园土壤生物活性及梨果实品质的影响,【方法】在7 a生梨树行间覆土套种平菇,将出菇后的菇渣旋耕还田,以不套种平菇为对照,测定分析梨园0～60 cm不同土层中细菌、放线菌、真菌数量,微生物量碳、量氮,脲酶、蔗糖酶、磷酸酶、过氧化氢酶活性以及成熟梨果实品质。【结果】结果表明,套种平菇显著提高0～40 cm土层3大类群土壤微生物数量、生物量及脲酶、蔗糖酶、磷酸酶、过氧化氢酶活性,并随套种年限的增加趋于增加。连续3 a套种平菇处理的细菌、放线菌、真菌数量较对照提高47.4%、32.0%、125.1%;微生物量碳、量氮比对照提高25.6%、28.1%;土壤脲酶、蔗糖酶、磷酸酶、过氧化氢酶活性提高42.3%、47.2%、29.5%、11.6%。土壤微生物数量、生物量、脲酶、蔗糖酶和磷酸酶活性随土层加深均有所降低,而过氧化氢酶活性则呈升高趋势。套种平菇后能不同程度改善果实品质,显著提高了梨果单果质量、硬度、可溶性固形物及可溶性糖含量,降低了可滴定酸含量。【结论】套种平菇对提高梨园0～40 cm土层土壤肥力、改善梨品质有显著效果。     

Effects of urea formaldehyde foam soil amendment on growth and response to transient water deficit stress of potted Flindersia schottiana saplings

Hydrocell™is a urea formaldehyde resin foam (UFRF) product used as a soil amendment. It is proposed to improve the physicochemical properties (viz. water relations and aeration) of the plant root zone. Flindersia schottiana is a tree species used in the ornamental horticulture industry. This study investigated the potential of Hydrocell™ [0–50% (v/v) incorporation rates] to promote growth of F. schottiana saplings during containerized nursery production in composted pine bark medium. The growth response of the potted saplings to transient water stress was also assessed. In addition, growth of F. schottiana saplings potted into three different soil types (sand, loam, clay) was assessed in the presence and absence of 30% (v/v) Hydrocell™. Under well-watered conditions in composted pine bark, Hydrocell™ treatments enhanced sapling leaflet numbers, with 30% (v/v) being the most beneficial treatment. However, no consistent significant differential effects of incorporation rate on either plant height or stem diameter were recorded. Extended time to wilting upon withholding irrigation was achieved, with the optimum Hydrocell™ rate being 10% (v/v). Among the three soil types compared, use of 30% (v/v) Hydrocell™ resulted in improved growth of potted F. schottiana saplings in the sand and loam soils, but not in the clay soil. These findings suggest that the UFRF, Hydrocell™, holds limited promise as a soil amendment for trees in the nursery phase. Optimum incorporation rates (v/v) would need to be determined for individual media types, specific irrigation regimes and individual taxa.     

Plant growth,water relations and transpiration of two species of African nightshade (Solanum villosum Mill. ssp. miniatum (Bernh. ex Willd.) Edmonds and S. sarrachoides Sendtn.) under water-limited conditions

The adaptation to drought stress of two African nightshade species, Solanum villosum and S. sarrachoides was investigated in pot and field experiments between 2000 and 2002. Two genotypes of S. villosum (landrace and commercial) and one accession of S. sarrachoides were grown under droughted, moderate stress and well-watered conditions. Leaf expansion, stem elongation and transpiration began to decline early in the drying cycle with fraction of transpirable soil water (FTSW) thresholds of 0.46–0.64. Osmotic adjustment (OA) of both species was in the range of 0.16–0.19 MPa and could not maintain positive turgor below water potentials of −1.80 to −2.04 MPa. The responses evaluated were similar in the three genotypes suggesting similar strategies of adaptation to drought stress. Under field conditions, the S. sarrachoides accession showed a higher leaf area than the S. villosum commercial genotype. It is concluded that the three African nightshade genotypes have limited OA capacity and adapt to drought mainly by regulating transpiration. This was achieved by reduction of leaf area. In general, it is necessary to maintain FTSW above 0.5–0.6 to prevent decline in leaf expansion, stem elongation, and transpiration.     

Cropping effects on the loss of apple fruit firmness during storage: The relationship between texture retention and fruit dry matter concentration

Firmness is a primary measure of apple fruit texture, the key determinant of eating quality of apples. Despite the well developed understanding of the process of firmness loss in storage, there is very limited information concerning pre-harvest and at-harvest causes of the variation in fruit quality in the marketplace. The objective of the present study was to investigate the respective roles that the factors of time and intensity of crop thinning, fruit size and fruit dry matter concentration (DMC) each may have in determining fruit firmness of ‘Royal Gala’ apple at harvest and during storage. Loss of firmness during storage of all thinning treatments and of fruit size and DMC categories was described by a bilinear equation. Time of thinning did not influence any aspect of fruit softening during air storage at 0.5 °C. Comparing the crop loads, a lower crop load (100 fruit per tree) resulted in firmer fruit at harvest. The loss of firmness during storage associated with crop load occurred because fruit from the lowest crop load softened more rapidly during the second slow phase of softening. Fruit firmness was positively correlated with fruit size where larger fruit were slightly firmer than smaller fruit at harvest but not after storage. The softening profiles of different sized fruit were similar except for a class of extremely small fruit, which appeared to soften more rapidly during the second slow softening phase of storage. Both at-harvest and post-harvest fruit firmness were influenced by fruit DMC. Fruit firmness at harvest increased significantly as fruit DMC increased from 13% to above 16%. Despite having significantly different initial firmness, all fruit classes with DMC higher than 13% softened at a similar rate during both the initial rapid and second slow softening phases and the transition between the two phases occurred after the same time in storage. In contrast, fruit with very low DMC, less than 13%, had a greater rate of softening in the second phase. These results indicate that variation in fruit firmness at harvest and after storage is influenced by processes that affect and alter fruit DMC during fruit development. In this respect crop load control, which is used to improve fruit size, was also an important factor in altering fruit DMC, thereby affecting firmness at harvest and after storage. Furthermore, the effects of DMC on fruit firmness were independent of fruit size.     

不同光质对丰香草莓生长发育的影响

研究了相同光强下不同光质对丰香草莓生长发育的影响。结果表明,不同光质膜处理对草莓的生长结果、干物质分配和果实品质均有影响。与中性膜相比,绿膜和红膜下草莓植株的叶柄长度和叶面积显著增加,而蓝膜的叶柄长度和叶面积明显较低。光质不同也影响草莓干物质的分配,干物质向叶片和叶柄分配比例绿膜最高,蓝膜最低,其它膜之间相近。而干物质向果实、冠状茎和根系中的分配比例均以蓝膜最高,其次为红膜,绿膜最低,黄膜与中性膜相近。红膜下生长的草莓,产量最高、果实最大;蓝膜下可溶性固形物含量、抗坏血酸含量和固酸比最高;而绿膜下则产量最低、果实最小、可溶性固形物含量和固酸比最低。抗坏血酸含量的高低与不同膜中的紫外和蓝紫光的比例一致,与红光/蓝光比值相反。     

Behavior of arazá (Eugenia stipitata Mc Vaugh) fruit quality traits during growth,development and ripening

The period between fruit set and full ripening of arazá fruit grown in the Colombian Amazonia was 55 ± 5 days. Three stages of a sigmoidal growth were identified and longitudinal and equatorial traits fitted a logistic model better than three-degree polynomial models. Fruit growth clearly exhibited three different physiological stages, identified as follows: S1, involving cellular division during the first 14 days; S2, maximum fruit growth, during which cellular expansion took place (up to day 50), and a final S3 state of 5 days to reach physiological maturity. After this time, the fruit can be harvested with a dull green coloration. Parenchyma was the principal fruit tissue, and no support tissues (sclerenchyma or collenchyma) were evident. The respiratory pattern of arazá fruit was climacteric, with maximum respiration rates of around 200 mg CO₂ kg⁻¹ h⁻¹, preceded by a peak of ethylene production (20 μL C₄H₄ kg⁻¹ h⁻¹), a change in skin color from green to yellow, a total soluble solids value of 5°Brix, an increase in the sucrose and fructose content up to 2.8 μmol g⁻¹, a pH which increased to 3 units, and a decrease in titratable acidity to 400 mmol H⁺ L¹⁻. Malic acid was the main organic acid in the edible pulp and ascorbic acid was present in a concentration of 17.8 μmol g⁻¹. Skin color (as measured by hue angle) combined with titratable acidity and fruit firmness can be recommended as harvest indices for arazá fruit.     

Root zone temperature,plant growth and yield of broccoli [Brassica oleracea (Plenck) var. italica] as affected by plastic film mulches

Plastic film mulches are often associated with increases in plant growth and yield of vegetable crops. Few studies, however, report on the effect of plastic film mulches on root zone temperature on broccoli. The objectives of this study were to determine the effects of colored plastic mulches on root zone temperature and broccoli plant growth and yield Broccoli (‘Packman’) plants were grown using plastic film mulch and drip irrigation. The treatments consisted of plastic film mulch (black, blue, gray on black, red, silver on black, and white on black mulches) and bare soil. Colored plastic film mulches affected root zone temperature and the accumulation of soil degree-days. Mean daily RZT, maximal daily RZT and degree day accumulation in the soil were highest in dark-colored mulches (blue, black, red, and gray) and lowest in light-colored mulches (silver and white), while minimal daily RZT was highest in silver mulch and lowest in white mulch. Silver mulch showed the smallest diurnal fluctuations in RZT among plastic mulches, with the highest RZT during the night and among the lowest in the afternoon. Colored plastic mulches also affected broccoli plant growth and yield, although the effect of mulches was more dramatic in the spring than in the fall seasons. Broccoli yield was linearly related to both the vegetative top dry weight and root dry weight of mature plants. Broccoli yield was little affected at mean RZT of <21 °C but increased with increasing mean RZTs above 21 °C up to 25 °C. Thus, broccoli plant growth and yield responded more favorably to dark-colored mulches than to light-colored mulches, suggesting that broccoli benefited from increased soil warming. No high RZT stress effects on broccoli plant growth or yield were observed in this study. Thus, this study suggests that plastic film mulches, particularly the dark-colored mulches, may be an option for spring broccoli production in areas with cool conditions early in the spring.     

The effect of trunk electric vibration on the growth,yield and fruit quality of peach trees (Prunus persica [L.] Batsch)

To determine the effect of electric vibration on the growth, yield and fruit quality of peach electric vibrators that provided intermittent perturbation of 6500 rpm for 15 min every 6 h were firmly attached to the trunks of peach trees. Electric vibration resulted in the reduction of shoot length by 80% but had no significant effect on fruit weight, acid content and Brix. In another experiment, electric vibrators (for 15 min every 2 h) were attached to the branches after summer pruning. The regenerated shoots from the treated branches showed more than 500% reduction in length compared to the untreated ones. Even the regenerated shoots of untreated branches nearby the vibrator showed 60% reduction in length. Ethylene production and ACC content in the shoot tips of treated branches were greater than that from control ones.     

Influence of potential growth factors on the production of proembryogenic masses of Cyclamen persicum Mill. in bioreactors

Propagation in liquid culture, especially bioreactors, is one possible way to produce clonal propagules of Cyclamen persicum Mill. at a low cost. The current propagation method for C. persicum is from expensive hybrid seeds. This paper presents models of the potential effects of oxygen concentration, daily mean temperature, the difference between day and night temperature (DIF), and daily light integral on the development of proembryogenic masses of C. persicum Mill. in bioreactors. Each of the four growth factors was observed at three levels; oxygen concentration (50, 100 and 150% of fully oxygen saturated medium without cells), daily mean temperature (15, 20 and 25 °C), DIF (+10, 0 and −10) and daily light integral (0, 1.3 and 2.6 mol m⁻² day⁻¹). Two response variables, biomass growth and cell viability, were measured at day 0, 7, 14, 21 and 28 after start-up. The optimal values for biomass growth were 150% oxygen, 25 °C, 1.11 mol m⁻² day⁻¹ and DIF + 10. There was a stable positive linear effect from temperature. Oxygen showed a similar, but less stable effect. DIF gave maximum effect at the outer levels, and its optimum was the upper level +10. The optimal values for light were between 1.03 and 1.19 mol m⁻² day⁻¹. The optimal time for cell viability in the bioreactors was 10–11 days. Temperature and daily light integral had stable optima of 20.8 °C and 1.10 mol m⁻² day⁻¹. For oxygen the optimum was more unstable, but in most cases it was below 100%. There was no significant effect of DIF on cell viability.