Physiological effects of pruning in rose plants cv. Grand Gala

The effect of pruning in rose plants (cv. Grand Gala) was studied in different types of leaves, focusing on chlorophyll (Chl) a fluorescence, carbohydrates, ammonium content, nitrate reductase (NR) activity and biomass parameters. Results on pruned plants showed a higher maximum efficiency of photosystem II (PSII) of dark-adapted leaves, a higher actual quantum yield and a higher proportion of PSII reaction centres that are open, but a lower non-photochemical quenching, indicating a lower energy dissipation as heat, compared to non-pruned plants. These results related to Chl a fluorescence, indicate that pruned plants have a higher capacity for better promoting the photosynthetic light reaction than non-pruned plants. The increased nitrate reductase activity in pruned compared with non-pruned plants, can result from a higher photosynthetic activity resulting in a lower NH₄⁺ accumulation in leaves. Pruning promoted a large number of metabolic sinks (flower removal) that may cause depletion of stored carbohydrates flowing from lower plant parts (arched shoots) to the new developing flower shoots. However, although in a lower concentration, carbohydrate contents were sufficient to promote the development of new flower shoots since the yield was similar for pruned and non-pruned plants. However, pruned plants showed higher turgor than non-pruned plants.     

Plant carbohydrate partitioning of Lachenalia cv. Ronina during bulb production

Carbohydrate partitioning was investigated in different plant organs of Lachenalia cv. Ronina during bulb production under a low temperature regime. At 4-week intervals, data were collected on bulb, roots, leaves, inflorescence and carbohydrate composition. The roots and especially the bulb were found to be the main starch sinks of the plant, whilst the leaves and the inflorescence were the main source for soluble sugars. Changes in the starch concentration closely followed dry weight changes in the bulb during the growing season. When bulbs were initially exposed to a low temperature, starch was converted to soluble sugars, but thereafter sugars were low, indicating continued export and conversion to starch. Low sugar levels in the leaves and high levels in the inflorescence, with continuous starch increase in the bulb and roots, probably indicate that the inflorescence, but especially the leaves, produced ample photosynthates during the growing season.     

The role of carbohydrate reserves in evergreen tree development,with particular reference to macadamia

We take three approaches to more clearly define the role of carbohydrate (CHO) reserves in the development of evergreen trees. First, we examine the lychee and macadamia literature to develop a whole tree carbon budget to show that current photosynthate makes a greater contribution to the carbon for new growth than CHO reserves. Second, we show that the presence of leaves is sufficient for the production of a functional new shoots on small, girdled branches with few CHO reserves. Third, we use a shade experiment to show that short-term suppression of whole-tree photosynthesis can severely affect new shoot development. Subsequent decapitation of all branches on both the shaded and control trees resulted in faster bud release in the shaded trees, notwithstanding lower CHO reserves.     

Isolation and expression analysis of differentially expressed genes in stem tissue of the Greek lemon cv. Adamopoulou

Lemon (Citrus limon (L.) Burm. f.) is susceptible to mal secco, a serious vascular disease caused by the fungus Phoma tracheiphila (Petri) Kant. and Gik., as well as low temperatures. The greek lemon cultivar Adamopoulou, thought to be derived from the Portuguese cultivar Lisbon, exhibits enhanced resistance to mal secco and cold as opposed to cv. Lisbon. Suppression subtractive hybridization (SSH) was employed for the isolation of differentially expressed genes in lemon stem tissue. A subtractive cDNA library was constructed and a total of 296 clones were sequenced. The obtained sequences were edited, resulting in 56 non-redundant ESTs. Sequence analysis revealed homology to previously identified genes involved in defense mechanisms against biotic and abiotic stresses, as well as sequences with no significant similarity in the GenBank. Selected ESTs were analyzed by real-time PCR for confirmation purposes. This analysis revealed significant expression differences between the two cultivars for genes expressing allantoinase, ultraviolet-B-repressible protein, 4-coumarate:CoA ligase and other proteins that are known to be upregulated under biotic and abiotic stress conditions.     

Effects of sink removal on leaf photosynthetic attributes of rose flower shoots (Rosa hybrida L., cv. Dallas)

Two experiments were conducted under greenhouse conditions to evaluate the effects of sink removal (flower shoot harvest and debudding) on the gas-exchange capacity (i) of leaves left on the parent shoot after flower shoot harvest and (ii) of flower shoot leaves after flower-bud removal. In the first experiment, gas-exchange measurements were performed on three 5-foliate leaves (leaf 1: uppermost parent shoot leaf, and two leaves inserted just below: leaves 2–3). It was found that, after bud sprouting, the leaf nearest to the young growing shoot (leaf 1) experienced a significant reduction in leaf maximum net CO₂ assimilation rate, A_lm, stomatal conductance, g_s, and transpiration rate, E_l, over time in comparison to the corresponding values observed for leaves 2–3. Leaf water use efficiency, WUE, significantly changed over time, while the ratio of leaf internal to ambient CO₂ concentration, C_i/C_a, was rather conservative throughout the entire shoot growing period. In the second experiment, leaf gas-exchange measurements were performed for adult flower shoots that were either debudded or left intact. Both types of shoots exhibited a similar along-shoot distribution pattern of physiological fluxes, g_s, and WUE. Bud removal did not significantly affect the magnitude of gas-exchange, with the exception of E_l. One week after bud removal, only slight differences were observed for A_lm, g_s and E_l between the two types of shoots. These results suggest (i) that the contribution of the uppermost parent shoot leaf to the assimilates demand of newly growing shoot significantly affects its photosynthetic capacity; and (ii) that flower-bud removal does not change the overall photosynthetic capacity of the flower shoot leaves, which divert the surplus of produced assimilates towards alternative sink organs and plant reserve pools.     

Effects of defoliation on fruit growth,carbohydrate reserves and subsequent flowering of ‘Hayward’ kiwifruit vines

A partial defoliation study was carried out on ‘Hayward’ kiwifruit vines with the aim of evaluating effects on fruit yield, changes in concentration of carbohydrates, and return bloom. At full bloom, ‘Hayward’ kiwifruit vines trained to the pergola system were submitted to 0% (control), 50% and 75% defoliation in the 2.0 m wide central horizontal area of the canopy. This area represents the vine ‘replacement cane zone’ (RCZ), whereas the remaining external area represents the ‘fruiting zone’ (FZ). Removing 50% of the leaves resulted in a small (−9 g in the RCZ and −3.3 g in the FZ), but significant, reduction in fruit weight compared to the control vines. More severe defoliation (75%) reduced fruit weight by 13 g in the RCZ and 7 g in the FZ. The defoliation treatment reduced the concentrations of starch and total soluble carbohydrates (glucose + fructose + sucrose) in the shoots and starch in trunk bark compared to those in control vines. The treatments caused a large reduction in return bloom, expressed as number of flowers per winter bud, by about 25% and 53% in vines with 50% and 75% defoliation, respectively.     

Sucrose synthase dominates carbohydrate metabolism and relative growth rate in growing kiwifruit (Actinidia deliciosa, cv Hayward)

Changes in fruit growth rate, carbohydrate content (glucose, fructose, sucrose and starch) and enzyme activity (sucrose synthase, UDPglucose pyrophosphorylase, fructokinase, glucokinase, sucrose phosphate synthase, ADPglucose pyrophosphorylase and invertases), in the external pericarp of kiwifruit, were measured throughout the growing season. Sucrose synthase showed the highest activity among the sucrose cleaving enzymes during large part of the growing season. The activity of invertases were much lower than that of sucrose synthase until ripening started. Sucrose synthase showed a tight although not linear relationship with the fruit RGR. Furthermore, sucrose synthase showed linear and significant correlations with the activities of both fructokinase and UDPglucose pyrophosphorylase indicating a strong co-regulation of the activities of these three enzymes involved in sucrose cleavage and sink strength, in kiwifruit. Sucrose synthase is suggested to be the dominating enzyme in the cleavage of imported carbon in kiwifruit, in tight coordination with fructokinase and UDPglucose pyrophosphorylase.     

设施栽培灵武长枣、冬枣休眠特性研究

以宁夏设施栽培灵武长枣、冬枣为试材,采用温度记录仪和水浸枝条萌芽法,应用3种需冷量估算模型(≤7.2℃模型、0~7.2℃模型和犹他模型),对其需冷量进行估算,并测定了相关生理指标。结果表明:不同估算模型下相同枣品种需冷量值略有差异;以≤7.2℃模型估算,设施栽培灵武长枣需冷量值为446h;设施栽培冬枣为470h。适宜的萌芽温度20~25℃,在休眠后期至萌芽初期,枝条可溶性糖含量呈下降趋势,蛋白质含量呈上升趋势。     

Carbon storage by urban tree cultivars, in roots and above-ground

Urban trees can favorably affect factors underlying global warming by storing carbon and by reducing energy needs for cooling and heating buildings. To estimate carbon stored in roots and above-ground portions of trees, data was collected consisting of whole tree sampling of Amelanchier, Malus, Pyrus, and Syringa cultivars. Roots were excavated using an Air-Spade^™. Regression analysis resulted in two equations for predicting total carbon storage based on height and diameter of trees up to 20 cm dbh: Y = 0.05836 (dbh²) for root carbon storage, and Y = 0.0305 (dbh² × h)^0.9499 for above-ground carbon storage, explaining 97% and 96% of the variation, respectively. Average carbon stored in roots of various cultivars ranged from 0.3 to 1.0 kg for smaller trees, those 3.8 to 6.4 cm dbh, to more than 10.4 kg for trees 14.0 cm to 19.7 cm dbh. Average total carbon stored by cultivars ranged from 1.7 to 3.6 kg for trees less than 6.4 cm dbh to 54.5 kg for trees larger than 14.0 cm. The data from these equations apply mainly to trees in nurseries and recently transplanted trees. Comparisons showed that above-ground estimates from previous studies using a sampling technique overestimated values obtained from actual above-ground weights.     

Light acclimation in rose (Rosa hybrida cv. Grand Gala) leaves after pruning: Effects on chlorophyll a fluorescence,nitrate reductase,ammonium and carbohydrates

Changes in light intensity have a particular effect on the photosynthetic apparatus. Most of the studies on light acclimation in higher plants have focused on the effects of fixed light intensity. Few works deal on sudden changes in light intensity due to pruning for long periods of time. Pruning the bent shoots in roses (cv. Grand Gala) can modify the light interception in internal leaves and change their photosynthetic reactions. Before pruning, internal leaves were acclimated to low light intensity and after pruning, internal and external leaves received the same light intensity. The aim of this work was to find out how the photosynthetic light reaction, measured by chlorophyll (Chl) a fluorescence in internal and external leaves of arched shoot could be modulated by light changes. Other parameters described as light dependent were also measured: nitrate reductase (NR) activity, NH₄⁺, sucrose and starch levels. Internal and external leaves in rose have shown a high plasticity, rapid and dynamical acclimation, in response to changes in incident sunlight produced by pruning, that can be explained by Chl a fluorescence parameters. The modified NR activity, NH₄⁺, sucrose and starch levels were difficult to associated with light intensity changes, and their modulation could be the response to long-time light acclimation.     

心里美萝卜生长动态及养分吸收规律

对心里美萝卜生长动态及氮、磷、钾、硫吸收规律的研究结果表明：植株鲜重、干重以出苗后６１～７５天增长最快;肉质根产量在６５５８９ｋｇ／ｈｍ２时,平均每生产１０００ｋｇ肉质根,植株需吸收Ｎ２．１１９ｋｇ、Ｐ２Ｏ５１．３０６ｋｇ、Ｋ２Ｏ２．４５１ｋｇ、Ｓ０．５８９ｋｇ,比例为１．００∶０．６２∶１．１６∶０．２８;出苗后３１～７５天是植株吸收养分的主要时期;收获时植株吸收的各种养分主要贮存在肉质根内。     

灵武长枣多糖含量测定的研究

灵武长枣样品经脱脂,脱小分子糖后,用蒸馏水沸水浴浸提、醇沉、洗涤得灵武长枣多糖,含量测定采用苯酚-硫酸比色法,用精制多糖测得其多糖对葡萄糖的换算因子。建立了一种简便、准确测定灵武长枣多糖含量的方法。结果表明:该方法测定简便可行,重现性较好,平均回收率为97.11%,所测全红灵武长枣样品中多糖含量为13.30%。     

六月鲜枣愈伤组织诱导及胚状体发生

采用5因素4水平的正交试验设计,对六月鲜枣的幼叶、嫩茎、冷藏5d后的花药、花后48～50d的胚乳,利用3因素3水平的正交试验设计,对花后58～60d的幼胚及子叶,进行愈伤组织诱导再分化试验。探讨了不同激素、碳源和基本培养基对产生愈伤组织的影响。结果表明:碳源对胚乳、花药器官,基本培养基对嫩茎、幼叶、花药愈伤组织的诱导有显著影响,而且生长素种类和浓度对不同外植体的愈伤组织诱导作用不同;嫩茎、子叶及幼胚较易诱导产生愈伤组织,但只有子叶及幼胚产生的愈伤组织具较强的再生能力,并可诱导出不定芽,不定芽分化率分别为51.1%和9.5%,ZT较BA易诱导愈伤组织产生不定芽,不定芽转移生根成苗获得了完整植株。另外,用子叶及幼胚培养获得了大量胚状体,且胚状体最终可发育成苗。     

Molecular fingerprinting of a new Kiwifruit cultivar (cv. Tsehelidis) and comparative analysis with cv. Hayward according to physicochemical properties

“Tsechelidis” is a new kiwifruit cultivar of Actinidia deliciosa species that was developed in North Greece (Episkopi, Imathia) through collaboration between Farmaplant S.A and Department of Agriculture Crop Production and Rural Environment, University of Thessaly.     

无子西瓜郑抗4号的体细胞胚诱导及植株再生(英文)

以无子西瓜(CitrulluslanatusMansfeld)郑抗4号无菌苗子叶为外植体,进行了体细胞胚发生及植株再生的研究,结果表明,无菌苗应先进行3d暗培养,然后采取光照16h/d和黑暗8h/d培养3d;将子叶的叶面朝下放置于培养基上的愈伤组织诱导率高于叶面朝上的培养方式;子叶诱导胚性愈伤组织的最适培养基配方为MS+6-BA2.0mg/L+KT1.0mg/L+GA31.0mg/L;诱导需要在黑暗条件下启动,进行7d暗培养,而生长分化于光照16h/d和黑暗8h/d条件下培养7d;继代3次得到的胚性愈伤组织最多;最适生根培养基配方为1/2MS+IBA0.3mg/L。体细胞胚胎诱导率最高为25%。胚性愈伤组织经进一步培养发育为成熟的体细胞胚胎,生根成为完整植株。     

马铃薯品种大西洋试管苗愈伤诱导研究

为筛选适合加工型马铃薯大西洋试管苗诱导愈伤的器官来源和培养基,以大西洋试管苗的叶和茎段为材料,分别在3种培养基上进行愈伤诱导,比较接种后10、20和40 d的出愈率及愈伤组织外观.结果表明:在接种10 d和20 d时大西洋茎段诱导愈伤的速度和出愈率均高于叶片的,在接种40 d时3种培养基均可诱导出大量的愈伤,但以MS添加3 mg/L 2,4-D和0.2mg/L KT的培养基上诱导产生的愈伤速度快、颜色亮黄、外观疏松且在随后的继代培养中不随培养时间延长而产生褐化现象.     

花叶良姜组培无菌体系的建立

以花叶良姜袋苗为试材,根茎腋芽为外植体,研究外植体预处理、灭菌消毒和外植体长度等因素对其无菌体系建立的影响。结果表明:实验室水培植株3d,根茎腋芽长3~5cm作外植体,用1.25‰HgCl_2灭菌消毒16min,花叶良姜外植体污染率24.2%,萌芽率72.7%,较有利于建立花叶良姜无菌体系。     

河套蜜瓜体胚发生及植株再生的研究

建立了一个河套蜜瓜体胚再生的方案 ,河套蜜瓜子叶在加有 2 ,4 D ( 1mg/L)、NAA ( 1mg/L)、BA ( 0 .5mg/L)和葡萄糖 ( 3% )的MS培养基上先暗培养 1周 ,然后转到光下 ,第 3周转移到不加任何激素的MS培养基中 ,继续在 16h光周期、 2 5℃下培养 ,得到成熟体胚后 ,拨离下来转移到新鲜MS培养基中继续萌发生长。     

多效唑对大叶黄杨、金叶女贞、紫叶小檗的抗旱性影响研究

采取盆栽控水法,研究多效唑对大叶黄杨、金叶女贞、紫叶小檗等绿篱植物抗旱性影响,以期为节水管理提供依据。结果表明:在干旱条件下,3种绿篱植物应用适宜浓度的多效唑可不同程度的增强抗旱性。单就抗旱性而言,大叶黄杨的适宜浓度范围为1.33~9.33 g/L,最佳浓度为6.67 g/L;金叶女贞和紫叶小檗适宜浓度均为1.33~4.00 g/L,最佳浓度为2.67 g/L。     

金叶卫矛的茎段培养及试管繁殖

以金叶卫矛带腋芽的茎段为外植体进行试管繁殖,筛选出各培养阶段适宜的培养基分别为：（１）腋芽萌生,ＭＳ＋６－ＢＡ２．０ｍｇ／Ｌ＋ＮＡＡ０．２ｍｇ／Ｌ;（２）分化及继代,ＭＳ＋６－ＢＡ２．０ｍｇ／Ｌ＋ＮＡＡ０．５ｍｇ／Ｌ;（３）生根,１／２ＭＳ＋ＩＢＡ０．３ｍｇ／Ｌ＋ＮＡＡ０．５ｍｇ／Ｌ。