Size of tuber propagule influences injury of 'Kennebec' potato plants by constant light

Chlorosis and necrotic spotting develop on the foliage of particular cultivars of potato (Solanum tuberosum L.) when grown under constant light. 'Kennebec', a cultivar severely injured by constant light when propagated from tissue-cultured plantlets, also was injured when plants were propagated from small tuber pieces (approximately 1 g). However, plants did not develop injury when propagated from large tuber pieces (approximately 100 g). Plants from large tuber pieces grew more rapidly than plants from small tuber pieces. The role of plant vigor and carbohydrate translocation in controlling injury development is discussed.     

Growth and productivity of potato as influenced by cultivar and reproductive growth: II. Growth analysis,tuber yield and quality

A field experiment was conducted under sub-humid tropical conditions in Ethiopia using determinate cultivars Al-624, Al-436, CIP-388453-3(A) and CIP-388453-3(B) to study the effect of flowering and berry set on the growth, tuber yield, and quality of potato. Three treatments, viz. debudded, flowering, and fruiting plants were compared and standard growth analysis techniques were applied to study the growth pattern. Fruiting plants exhibited reduced leaf area index, tuber growth rate, and partitioning coefficient, but had higher crop growth rates and net assimilation rates. Fruit development reduced total and marketable tuber mass and tuber number without affecting the unmarketable component. Cultivars varied with respect to tuber yield, tuber number, size distribution, specific gravity, dry matter content, and nutrient composition. Fruiting reduced tuber specific gravity and dry matter content while increasing P, K, Mg, Fe, and Mn content of the tubers. Reproductive growth did not affect tuber Ca, S, Cu, and Zn concentrations. The field experiment demonstrated that reproductive growth restricts vegetative growth and reduces tuber yield and dry matter content of potato.     

Responses of field grown tomato plants to arbuscular mycorrhizal fungal colonization under varying intensities of drought stress

The effects of root colonization by the arbuscular mycorrhizal (AM) fungus Glomus intraradices Schenck and Smith on growth, flower and fruit production, and fruit quality were studied in field-grown tomato plants exposed to varying intensities of drought stress. Inoculated (M+) and non-inoculated (M−) tomato seedlings were exposed to varying intensities of drought stress by adjusting irrigation intervals. Mycorrhizal plants had significantly higher uptake of N and P in both roots and shoots regardless of intensities of drought stress. AM inoculation also significantly increased shoot dry matter and the number of flowers and fruits. The fruit yields of M+ plants under severe, moderate, mild drought-stressed conditions were higher than M− plants by 24.7%, 23.1%, 16.2% and 12.3%, respectively. Furthermore, M+ plants produced tomato fruits that contain significantly higher quantities of ascorbic acid and total soluble solids (TSS) than M− plants. Mycorrhizal effects increased with increasing intensity of drought. The overall results suggest that mycorrhizal colonization affects host plant nutritional status, water stratus and growth under field conditions and thereby alters reproductive behaviour, fruit production and quality of fruits under both well-watered and drought-stressed conditions.     

Responses of blackcurrant bushes to post-harvest moisture stress

Potted blackcurrant plants subjected to moisture stress following harvest produced 50% less total fruit yield in the following season than plants which received regular irrigation. The factors which contributed to this effect were a reduction in the numbers of productive buds, flowers per bud and fruit set. An increase in seed number per fruit in response to the stress suggested that reserve carbohydrates accumulated during the autumn may have been the controlling factor in fruit set.Bud-burst in the stressed plants was both early and uneven, radial growth was reduced, and there was no evidence of starch accumulation at the onset of dormancy.All plants received the same irrigation treatment in the spring following treatment, and there was no significant difference in fruit size except for a few positions at the distal end of the strig. Fruit on stressed plants in this case were the smallest.     

栝楼雌雄植株激素和多胺含量的比较

在栝楼生长发育各阶段,采用高效液相色谱技术分别对雌雄植株叶片内源激素及多胺含量进行分析。结果表明,吲哚乙酸（IAA）含量在所测定的生长发育期,雌株始终高于雄株,而脱落酸（ABA）含量雌株始终低于雄株;玉米素核苷（ZR）和赤霉素（GA1/3）含量在营养生长期雄株高于雌株,雄株进入生殖生长阶段后迅速下降,而雌株继续保持上升趋势,直至雌株进入生殖生长期后才迅速下降。雌株叶片中亚精胺（Spd）含量极显著高于雄株;精胺（Spm）含量在营养生长期雄株显著高于雌株,而在雌株进入生殖生长后雌雄株间差异不显著;腐胺（Put）含量在营养生长期雄株显著高于雌株,而在雌株进入生殖生长后雌株显著高于雄株。试验结果表明：高含量的IAA和Spd有利于栝楼雌花发育,而高含量的Put和Spm有利于雄花发育。当雌雄花盛开后,多胺均呈下降趋势,Put和Spm在雌雄株间含量差异越来越小。     

Involvement of proline in response of chickpea (Cicer arietinum L.) to chilling stress at reproductive stage

Chickpea is sensitive to chilling stress, especially at its reproductive stage and experiences abortion of flowers and poor pod set at temperatures below 10 °C. The metabolic controls governing chilling-sensitivity in chickpea, particularly involving proline are not known. Hence, in the present study we explored the role of proline in this regard. A set of chickpea plants (cv. GPF2) growing under warm conditions of the glass house (temperature – 28/14 °C as average maximum and minimum till early flowering stage) was exposed to low temperature conditions of the field (8.3–9.6/2.8–5.3 °C; average maximum and minimum temperature, respectively) during the onset of reproductive phase while another set of plants continued to grow under warm conditions. In case of chilling-stressed plants, one set of the plants was treated with 10 μM proline while the other set not treated with proline served as control under low temperature conditions. In untreated chilling-stressed plants, the endogenous proline increased to 230 μmol g⁻¹ dry weight (DW) on 4th day of stress and decreased thereafter to reach 28 μmol on 7th day. In plants treated with 10 μM proline, its endogenous content reached 310 μmol g⁻¹ DW on 4th day and stayed significantly higher than untreated chilling-stressed plants. The proline-treated plants showed significant improvement in retention of flowers and pods leading to better seed yield compared to the untreated ones. The proline-applied plants also had greater pollen viability, pollen germination, pollen tube growth and ovule viability. The stress injury measured as oxidative stress, electrolyte leakage, loss of chlorophyll and decrease in leaf water content was mitigated significantly in proline-treated plants. Additionally, proline application increased the level of sucrose and trehalose (cryoprotectants) in chilling-stressed plants. The studies revealed that proline application was significantly effective in reducing the impact of chilling injury on reproductive growth in chickpea.     

野生棘瓜砧木对黄瓜生长及抗逆性的影响

 以瓜类野生种(棘瓜) 和黑籽南瓜为砧木、‘中农21号’黄瓜为接穗, 研究了棘瓜嫁接对黄瓜植株生长发育、耐寒性、光合速率、产量、抗病性以及果实品质的影响。结果表明, 棘瓜嫁接可使‘中农21号’黄瓜的第1雌花开放期和始收期提前, 对根瓜质量、20节内的雌花数、株高、最大叶面积、叶片数、茎粗和节数的影响小于‘黑籽南瓜’嫁接处理; 前者的抗寒能力、净光合速率强于后者和自根苗;棘瓜嫁接对黄瓜具有增产、抗枯萎病、抗根结线虫的作用, 并且果实品质显著优于以黑籽南瓜嫁接的。     

Flower morphology and number of aubergine (Solanum melongena L.) in relation to fruit load and auxin application

The effect of fruit load and auxin application on the flower morphology and flower number of two aubergine cultivars was investigated under greenhouse conditions. The flowers of plants that did not set fruit showed only minor fluctuations in flower and pistil mass, and in style and anther length. However, when plants were allowed to set fruit by pollination, flower and pistil mass, and style (but not anther) length were significantly reduced during the stage of fruit growth. Style length was also reduced in flowers formed after fruit had been set parthenocarpically by the application of auxin (IAA), but there was no significant effect of IAA on style length in the absence of fruit development. The number of flowers was reduced in the presence of IAA (with or without fruit set), or following fruit set by pollination. It is suggested that fruit load and development affect flower mass and style length of aubergine whereas auxin influences the number of flowers.     

Evidence of drought-sensitive periods from flowering to maturity on highbush blueberry

The effects of water deficit on highbush blueberry (Vaccinium corymbosum L.) have been little studied. This study, conducted on container-planted shrubs, aimed at determining the influence of water stress on growth, water relations and fruit production of the plant during two consecutive years. Drought periods of approximately 3 weeks, as monitored from the transpiration of control plants, were applied at various phenological stages of plant development, from blossoming to harvest, so as to evaluate their direct effects. Highbush blueberry reacted very quickly to drought by reducing transpiration and stopping stem diameter growth and shoot elongation. Its ability to recover depended on the stress level and the drought implementation dynamics. Under moderate stress (35% less transpiration than a well-watered shrub) the recovery potential was almost complete. In all cases water stress during fruit growth and ripening strongly influenced yield by reducing the mean fruit weight and size. Drought after-effects, as assessed from one season to the other, were small, except when stress occurred during flower induction. In that case the number of flowers was reduced in the following year as well as the number of fruits, although fruit size was greater resulting in only a slight reduction in yield. In all cases, photosynthetic performance during the following year appeared not to alter, but water stress imposed to obtain large fruit cannot replace pruning without jeopardising the shrub architecture.     

Temperature effects on male fertility and flower and fruit development in Capsicum annuum L.

Temperature conditions strongly influenced the development of flowers and fruits of pepper (Capsicum annuum L.) plants. Low temperatures (LTR; 18°C day/15°C night) had much more effect on flowers and fruits than intermediate (ITR; 23°C day/18°C night) or high (HTR; 28°C day/23°C night) temperatures. LTR caused the formation of abnormal petals, stamens and gynoecium in the flowers. Stamens produced were deformed, in some cases partly carpel-like, produced abnormal non-viable pollen, and were thus functionally male-sterile. In the gynoecium, the ovary size of LTR-grown flowers was larger than that of ITR and HTR flowers, but the style elongation was inhibited. Fruits produced under HTR were larger than ITR and were seeded under both temperature regimes. Under LTR, small seedless fruits were produced, but normal seeded fruits were formed if flowers were pollinated with pollen from ITR- or HTR-grown flowers.     

AgNO_3不同处理时期和浓度对西葫芦性别表现和花粉活力的影响

为筛选出诱导西葫芦雄花的最佳时期和AgNO3浓度,于3个不同的生长时期,用3种不同浓度(300,400,500 mg/L)的AgNO3处理西葫芦幼苗。试验结果表明,在不同时期用AgNO3可提高西葫芦第一雄花节位,增加2花芽/叶腋数,减少雌花数,且处理时间越早,第一雄花节位越高,雌花数越多;同一处理时期,随着AgNO3浓度的增加,雌花数减少,2花芽/叶腋数增加,子叶平展期和1叶1心期用400 mg/L AgNO3处理西葫芦幼苗,雄花数最多,花粉活力最高;仅1叶1心期和2叶1心期可诱导两性花产生,且随着处理时间的推迟和AgNO3浓度的增加,两性花越多,植株长势减弱。研究结果表明,子叶平展期用400 mg/L AgNO3处理西葫芦幼苗,诱雄效果最佳。     

Effects of ethephon,GA3 and nutrient elements on sex expression of Chinese chestnut

The effects of ethephon or GA₃ on sex expression of Chinese chestnut (Castanea mollissima BL.) were opposite to the effects of these plant growth regulators on cucumber, pumpkin and Chinese white-flowered gourd. Ethephon at 100–500 mg 1^?1 inhibited the development of female flowers and promoted that of male flowers. GA₃ at 50–500 mg 1^?1 caused a significantly lower number of male inflorescences, but increased the number of female flowers. Urea applications decreased the number of male inflorescences and increased the number of female flowers. For plants grown on phosphorous-deficient soils, fertilizing with superphosphate also increased the number of female flowers. Spraying trees with GA₃, urea or a mixture of both increased the number of female flowers. Therefore, it is proposed that such applications should be employed at the onset of differentiation of flower primordia of Chinese chestnut to increase the ratio of female to male flowers.     

Growth,sex expression,pollen germination and yield in pepper as affected by chlorflurenol

Four-week old plants of pepper (Capsicum annuum L.) cultivar ‘Jawala’ were sprayed with an aqueous solution of chlorflurenol at concentrations of 50, 100, 150 or 200 mg/l. Chlorflurenol reduced the growth of the main shoot and the area of the leaf, weakened apical dominance, increased the growth and number of lateral branches, and reduced the growth and number of stamens. Induction of stamenless (pistillate) flowers was an interesting effect. The size, viability and germination of pollen grains were reduced by chlorflurenol. It caused an appreciable promotion in fruit-set up to a concentration of 150 mg/l and a drastic reduction at 200 mg/l, accompanied by increase and decrease of yield, respectively. Parthenocarpy was observed at 100, 150 and 200 mg/l.     

Efficient reduction of biomass,seed and season long pollen production of common ragweed (Ambrosia artemisiifolia L.)

Ragweed (Ambrosia artemisiifolia L.) is a noxious plant that not only is a troublesome agronomic weed that causes economic damage to agricultural crops but also − and even more importantly − causes severe health problems due to its severe allergenicity. The pollen of invasive ragweed has become a major allergenic risk factor in urban areas in newly occupied regions. Many urban areas prohibit herbicide application; thus, mowing is the most widely used control measure. Counting pollen is labour intensive; therefore, pollen production data are mainly based on estimations. Field experiments were conducted to determine the effects of different mowing scenarios, plant density and cutting height on the biomass, pollen production and seed production of common ragweed plants. Ragweed plants were mown twice: just before the flowering of terminal racemes (BBCH 59) and when the flowers of the re-sprouting lateral shoots reached BBCH 59. A 1- to 3-cm cutting height produced the greatest pollen reduction compared to that of intact control plants (94%) based on a season-long pollen collection. The number of female flowers also significantly decreased (97%). Compared to the control, the onset of pollen discharge was delayed by 5 weeks and the length of the pollen discharge period decreased from 9 to 4 weeks. The season-long unique and reproducible pollen production data can be integrated with airborne pollen modelling and population management strategies.     

Effects of temperature and daylength on growth and flowering of roselle, Hibiscus sabdariffa L.

Hibiscus sabdariffa L. was found to show an ambiphotoperiodic reaction, flowering both in short days and in extremely long days, but remaining vegetative (at least at 21–25° C) in a 16 h day. Flowering had a dual effect on growth. When floral induction was strong, lateral buds developed into flowers and the number of branches was proportionally reduced. The first stage of floral induction, however, was accompanied by a decrease of apical dominance. Plants shifted to long days after only a short stay at an inductive daylength, and plants moved to short days after a prolonged stay in long days, formed many more branches and a much greater vegetative mass than plants grown in continuous short days or long days.Plants were already sensitive to daylength in the cotyledon stage. Floral induction was not carried over from short days into long days. After marginal induction, floral buds reverted to vegetative shoots, or aborted and were replaced by a shoot from the axil of a bract.In short days, seedlings form shallowly three-lobed leaves until the generative stage, when only entire leaves are formed. In long days, the leaves are deeply five-lobed, also when the plant flowers.     

Influence of the Cytokinin, 6-Benzylamino-9-(Tetrahydropyran-2-yl)-9H-Purine,on the Growth and Development of Some Ornamental Crops

Foliar sprays of the synthetic cytokin, 6-benzylamino-9-(tetrahydropyran-2-yl)-9H-purine (PBA), increased branching in carnation, chrysanthemum, poinsettia, petunia and fuchsia, which showed varying levels of tolerance. In no instance did PBA reduce plant height. Applications of PBA to carnation and chrysanthemum stimulated branching in both intact and pinched plants. Treatment a few days prior to pinching produced more uniform development of new laterals. Response to the compound was most favourable under optimum growing conditions. Under relatively poor light intensity the laterals exhibited a reluctance for continued elongation and showed marked chlorosis. Application of PBA to flower buds at an early stage of development increased both the diameter and the fresh weight of carnation flowers or chrysanthemum inflorescences when fully open. Response to the compound decreased with age of the bud at the time of treatment. In carnation the effects on size were accompanied by an increase in petal area together with an increase in the number of primary petals produced. Relatively high concentrations also induced the formation of secondary growing centres from which varying numbers of additional petals were produced. Relatively large numbers of these secondary centres within a flower resulted in an increased incidence of calyx splitting. These centres were not observed in chrysanthemum. The formation of secondary growing centres could also be induced by GA₃ and IAA. However, while these growth substances increased the diameter and fresh weight of carnation flowers, unlike cytokinins they had no apparent effect on the number of primary petals formed. Finally PBA was also observed to increase the longevity of cut flowers of carnation. This was particularly apparent at relatively low temperatures.     

Potato growth in response to relative humidity

Potato plants (Solanum tuberosum L. cvs. Russet Burbank, Norland, and Denali) were grown for 56 days in controlled-environment rooms under continuous light at 20C and 50% or 85% RH. No significant differences in total plant dry weight were measured between the humidity treatments, but plants grown under 85% RH produced higher tuber yields. Leaf areas were greater under 50% RH and leaves tended to be larger and darker green than at 85% RH.     

油菜素内酯对不同类型盐胁迫下辣椒种子萌发及幼苗生长的影响

在盐胁迫下,植物会受到盐离子的毒害,产生大量有毒自由基,导致自由基代谢失衡,膜脂过氧化程度加重,蛋白质降解,DNA链被破坏,最终使植物生长发育受阻。以辣椒为研究对象,研究了油菜素内酯(BR)对不同盐胁迫(中性盐、碱性盐)下辣椒种子萌发、幼苗生长发育的影响。结果显示,不同类型盐胁迫下辣椒种子的发芽率下降,BR浓度0.25 mg/L是恢复NaCl胁迫下辣椒种子萌发力最适合的处理浓度,发芽率为95.9%,发芽势为92.9%,均显著高于其他处理;BR浓度0.5 mg/L,是恢复NaHCO3胁迫下辣椒种子萌发力最适合的处理浓度,发芽率为92.1%,发芽势为90.7%,均显著高于未经BR处理的种子。BR能显著缓解不同盐胁迫对辣椒幼苗生长的抑制作用,NaCl胁迫下,BR浓度为0.25 mg/L时,对恢复幼苗茎质量作用明显,但对茎长作用不明显。NaHCO3胁迫下,BR浓度为0.5 mg/L时,对幼苗生长促进作用最为明显。     

Acclimatisation to mannitol-induced water deficit in miniature rose (Rosa hybrida) plantlets cultivated in vitro under autotrophic conditions

Summary

Miniature rose plantlets at the flower development stage were grown photo-autotrophically on MS medium and subsequently exposed to water deficits of –0.23, –0.32, –0.40, or –0.67 MPa osmotic potential ( _s) for 14 d. The _s in the culture medium was raised by increasing the concentration of mannitol, which caused abnormal floral development in terms of the flowering percentage and the number of flowers per plantlet, as well as delayed flowering. In vitro flowering and the number of flowers per plantlet declined significantly when miniature rose plantlets were exposed to water deficit stress at –0.40 MPa or –0.67 MPa. Reductions in growth, pigment degradation, chlorophyll a fluorescence, and net photosynthetic rate (Pn) were greatest in plantlets exposed to a water deficit stress of –0.67 MPa. This was particularly evident in the case of Pn, with a decline of 73.7% compared to non-stressed control plantlets. In contrast, proline levels increased in plantlets under water deficit stress, as proline performs a key role as an osmoprotectant under such conditions. The flowering stage in miniature rose plantlets is particularly susceptible to water deficit stress, which suppresses the development of reproductive organs. Knowledge of the responses to water deficit stress at the reproductive stage may be applied to identify effective indices for the selection of genotypes with increased tolerance to water deficit in miniature rose breeding programmes.     

The Effect of Temperature on Floral Behaviour,Pollen Tube Growth and Fruit Set in the Avocado

Avocado plants were kept in growth cabinets at 33°C day, 28°C night (33/28); 25°C day, 20°C night (25/20); and 17°C day, 12°C night (17/12), with a 12-h photoperiod and light intensity of 26000 1x. At 33/28 and 25/20 flowers opened in the afternoon as females and again the following morning as males (type B floral cycle) with some overlap of male and female stages at 25/20. At 17/12 very few flowers had a female stage, the majority opening once only as males. The duration of the flowering period decreased with a rise in temperature as did total number of flowers opening. Reproductive growth was inhibited in favour of vegetative growth at 33/28, as exhibited by smaller floral parts and abscission of buds and flowers. The rate of pollen tube growth increased with a rise in temperature, but abnormal growth was frequently observed at 33/28 and tubes failed to reach the ovary at 17/12. Endosperm and embryo development was observed to occur at 25/20 but not at 33/28 or 17/12 although a positive effect of pollination on fruit retention was evident at 33/28. This effect also occurred at 25/20 but not at 17/12. The most suitable temperature regime for floral behaviour, pollen tube growth and embryo development was 25/20.