姜荷花盆栽基质筛选初步研究

为筛选出适合姜荷花盆栽的基质配方,以椰糠、泥炭土、珍珠岩、红壤土等为材料,按不同比例混配成6种不同复合基质,研究不同复合基质配方对姜荷花生长发育的影响。结果表明,不同基质对姜荷花的萌芽率无明显影响,椰糠:泥炭土:珍珠岩:红壤=3:3:1:3(体积比)的复合基质是姜荷花盆栽较佳的栽培基质。     

不同基质对中苗期红掌生长及体内氮、磷、钾、钙、镁养分吸收利用的影响

通过不同体积比的粗砂、椰衣、椰糠、花生壳、谷壳的组合对中苗期红掌品种“热情”的处理,研究了不同基质配比对中苗期红掌植株的生长以及N、P、K、Ca、Mg养分吸收利用的影响,结果表明：配方为V椰糠∶V谷壳∶V花生壳＝2∶1∶1的栽培基质其各项理化性状更优,且最有利于中苗期红掌的生长及干物质的积累;中苗期红掌地上部及地下部N、P、K、Ca、Mg的利用率之间无显著规律性,但上述元素的积累量也在配方为V椰糠∶V谷壳∶V花生壳=2∶1∶1的栽培基质上最高。     

不同轻基质配方对油茶全光照扦插生根的影响

以10种轻基质材料为原料配置16种配方,并在全光照间歇喷雾条件下研究这16个配方对普通油茶优良无性系‘岑软3号’扦插生根的影响。结果表明,不同配方轻基质对油茶扦插生根有明显的影响,生根率从6.67%到100%不等,含有椰糠的轻基质配方生根情况明显优于不加入椰糠的配方。在含有椰糠的5种配方中,配方12(椰糠∶菌渣∶泥碳土体积比为4∶2∶1)的生根率最高,达100%,且成本在5个配方中从高到低位列第4,成本较低,最适合作油茶全光照喷雾扦插育苗的基质。     

不同基质配比对酸柚苗生长的影响

通过设置不同基质配比处理,筛选出较适合酸柚苗的基质配方,为无籽蜜柚优质砧木繁育提供理论依据。以椰糠、表土、甘蔗灰和菜籽饼为原料,按不同体积比配制9种栽培基质进行容器育苗,并测定各基质理化性质及苗木生长生理指标。结果表明:不同基质配比处理对酸柚苗的苗高、径粗、叶片增加数、总生物量及叶绿素含量方面影响显著,其中T5(1/3椰糠、1/3表土、1/3菜籽饼)综合表现最好,其次为T2(2/3椰糠、1/6表土、1/6菜籽饼)和T9(2/3表土、1/6甘蔗灰、1/6菜籽饼),表现较差的为T1(2/3椰糠、1/6表土、1/6甘蔗灰)、T4(1/3椰糠、1/3表土、1/3甘蔗灰)和T7(1/6椰糠、2/3表土、1/6甘蔗灰)。结合苗木生长状况及基质成本,认为体积比为1/3椰糠、1/3表土、1/3菜籽饼的栽培基质较适合酸柚苗生长。      

不同基质对香蕉组培苗生长及光合特性的影响

用椰糠与砖红壤土配成的6种不同基质栽培巴西香蕉组培苗,进行生长效果的比较；采用Li-6400便携式光合测定仪测定组培苗的净光合速率(pn)、蒸腾速率Tr等的日变化,通过相关性分析不同光合参数对净光合速率(pn)日变化的影响.结果表明:以椰糠:壤土=1:2配方对组培苗的生长效果最好；组培苗在不同基质下的净光合速率(pn)、蒸腾速率、气孔导度等变化趋势相似,其中以椰糠:壤土=1:2处理的数值最高,椰糠:壤土=4:1最低,胞间CO2浓度的数值则相反.6种基质栽培的香蕉组培苗以T2,即椰糠:壤土=1:2配制最适合香蕉组培苗生长.     

低硝酸盐含量的厚皮甜瓜无土栽培试验

在椰糠中添加一定比例的有机鸡粪肥可以使无土栽培中厚皮甜瓜的长势增强，但产量不一定增加。使用日本园艺全营养配方营养液和花无缺复合肥水溶液2种不同配方的营养液，对植株的生长势和产量及果实的可溶性固形物的含量影响差距并不大，但对成熟果实中的硝酸盐、亚硝酸盐含量因基质的不同有极显著的影响。选用新椰糠和有机鸡粪肥体积比为5：1作基质，使用花无缺复合肥水溶液作营养液可以生产出硝酸盐、亚硝酸盐含量符合国家水果标准的甜瓜。     

不同椰衣栽培介质对西瓜苗生长及生理特性的影响

研究不同的椰衣栽培介质对西瓜发芽的影响等，对于开展椰衣栽培介质基质化的应用具有重要意义。采用海南3市(县)5镇的11种椰糠为基础及配置2种(MIX1、MIX2)复合基质为测试材料，对椰衣介质13个处理的浸出液分别进行西瓜种子发芽实验、西瓜苗生长实验及相关生理测评等。结果表明：复合基质处理能保证西瓜苗生长，pH、EC值的大小是筛选优良椰衣复合基质的关键。椰衣介质MIX1处理是适宜西瓜生长发育的复合基质。     

巴西香蕉苗静置水培营养液配方的初步筛选

采用静置水培法，使用4种不同的营养液配方，并以清水培养和椰糠基质栽培为对照，对巴西香蕉苗进行生长比较试验。结果表明：在香蕉苗增加的生物量方面，BXM配方(巴西木植物营养液)处理与椰糠栽培的差异不显著，但与日本园试配方、Hoagland植物营养液配方、1/2 MS培养基营养元素配方和清水培养的差异显著；在株高和叶面积方面，均以椰糠栽培的最大，BXM配方处理的居次，接下来依次是Hoagland植物营养液配方、日本园试配方、1/2 MS培养基配方和清水培养。综上所述，在这4种营养液配方中，BXM配方是巴西香蕉苗生长的最适营养液配方。     

不同轻型基质对金钱树生长影响初报

采用单纯形-格子设计,将农林废弃物的椰糠、甘蔗渣、碳化稻壳、中药渣按体积比混合,得到35种轻型基质。结果表明,不同基质对金钱树的苗高、地径、根系生长、生物量有显著差异,经过综合评分,得出6种较好基质,分别为:100%椰糠;75%椰糠:25%碳化稻壳;50%甘蔗渣:50%中药渣;50%椰糠:50%中药渣;25%椰糠:50%碳化稻壳:25%中药渣;25%椰糠:25%甘蔗渣:25%碳化稻壳:25%中药渣。     

不同栽培基质对牛大力根系发育的影响

以不同比例泥土、砂、椰糠、草炭混合作为牛大力栽培基质，并进行盆栽试验，研究不同栽培基质条件下，基质的养分特征及其对牛大力根系生长和膨大状况的影响。结果表明：由草炭＋泥土(体积比2∶1)及草炭＋椰糠＋砂(体积比1∶2∶1)混合的基质pH值较适中，有机质含量与氮磷钾养分含量均较高，养分状况较理想，牛大力根系发达，但膨大块根较少；而泥土与砂混合基质各项指标均比较低，养分比较贫乏，牛大力根系发达，但块根膨大明显。在本研究条件下，基质养分不是根系膨大的关键因素，泥土含量高的基质可能因为较为理想的通气和热量条件而有利于块根的膨大。     

Nitrogen nutrition and temporal effects of enhanced carbon dioxide on soybean growth

Plants grown on porous media at elevated CO2 levels generally have low concentrations of tissue N and often appear to require increased levels of external N to maximize growth response. This study determines if soybean [Glycine max (L.) Merr. Ransom'] grown hydroponically at elevated CO2 requires increases in external NO3- concentrations beyond levels that are optimal at ambient CO2 to maintain tissue N concentrations and maximize the growth response. This study also investigates temporal influences of elevated CO2 on growth responses by soybean. Plants were grown vegetatively for 34 d in hydroponic culture at atmospheric CO2 concentrations of 400, 650, and 900 microliters L-1 and during the final 18 d at NO3- concentrations of 0.5, 1.0, 5.0 and 10.0 mM in the culture solution. At 650 and 900 microliters L-1 CO2, plants had maximum increases of 31 and 45% in dry weight during the experimental period. Plant growth at 900 microliters L-1 CO2 was stimulated earlier than at 650 microliters L-1. During the final 18 d of the experiment, the relative growth rates (RGR) of plants grown at elevated CO2 declined. Elevated CO2 caused increases in total N and total NO3(-)-N content and leaf area but not leaf number. Enhancing CO2 levels also caused a decrease in root:shoot ratios. Stomatal resistance increased by 2.1- and 2.8-fold for plants at the 650 and 900 microliters L-1 CO2, respectively. Nitrate level in the culture solutions had no effect on growth or on C:N ratios of tissues, nor did increases in CO2 levels cause a decrease in N concentration of plant tissues. Hence, increases in NO3- concentration of the hydroponic solution were not necessary to maintain the N status of the plants or to maximize the growth response to elevated CO2.     

Application of calcium and nitrogen for mitigating heat stress effects on potatoes

This study was designed to investigate the effect of calcium and nitrogen application during heat stress on leaf calcium concentration, transpiration rate, membrane thermostability, and biomass accumulation and partitioning. Micropropagated Russet Burbank potato (Solanum tuberosum L). plants were transplanted into 20 L pots containing 1:1 (v/v) soil: perlite and exposed to 30/20C (D/N) temperatures for four weeks (weeks 9–12 after transplanting) in a controlled-environment growth room. The maximum temperature was maintained for 6 hr during the middle of the 14 hr photoperiod. The nutrition treatments were N before stress (NBS), N during stress (NDS) and Ca and N during stress (Ca+NDS). Calcium was supplied as Ca(NO₃)₂. All treatments received the same total amount of nitrogen. Native soil Ca level without amendment (550 mg Ca/kg soil) was sufficient for potato plant growth under normal temperatures. Plants given Ca and N during heat stress had the highest leaf Ca concentration and transpiration rate during and 2 weeks after conclusion of the heat stress period. When measured after 4 weeks of heat stress, area and fresh and dry weight of the most recently mature leaf was significantly greater in NDS and Ca+NDS plants compared to NBS plants. Cellular membrane thermostability (measured as ion leakage from heat-treated leaf disks) was not affected by any treatment prior to heat stress. However, leaf tissue from Ca+NDS plants exhibited significantly higher membrane thermostability compared to NBS plants after 2 and 4 weeks of heat stress. At harvest, NDS and Ca+NDS plants had significantly higher leaf/stem (fresh weight ratio) values compared to NBS plants. Also, Ca+NDS plants had significantly greater total tuber and biomass values than NBS and NDS plants. Results of this study suggest that some detrimental effects of heat stress on plant growth and stomatal function may be alleviated by Ca and N application during heat stress. The data also suggest that mitigation of heat stress by Ca and N application during heat stress may maintain plant productivity when optimum growing temperatures are restored.     

Effects of Various Carbon Sources and Their Combinations on in vitro Growth and Photosynthesis of Banana Plantlets

abstract

The effects of various carbon sources, sucrose, glucose and fructose alone or in combination on the in vitro growth of banana plantlets were studied. Banana plants were cultured on the media supplemented with these carbon sources at 0.08 M for 13 weeks. The water potential of the medium was the highest in the medium supplemented with sucrose + glucose (-0.3 MPa), and was significantly lower in the medium supplemented with fructose alone or in combination with other carbon sources (-0.7 to -1.0 MPa) than in the other media. The leaf water potential was also the highest in the plants cultured on the medium supplemented with sucrose + glucose, and lowest in the plants cultured on that with fructose. The leaf water potential of plants cultured on sucrose + glucose, sucrose and glucose correlated well with their growth and photosynthetic activity, but the correlation was not observed in the plants cultured on fructose alone or in combination with other carbon sources. Plants cultured on fructose had a lower chlorophyll content (400 ptg dm^-2) and lower photosynthetic rate (3 μmol02 m^-2 s^-1) than those cultured on sucrose + glucose (15,950 μgdm^-2 for chlorophyll and 8.5 μmol02 m^-2 s^-1 for photosynthesis), and these differences were statistically significant. Both chlorophyll content and photosynthetic oxygen evolution were the highest in the plants cultured on sucrose + glucose, and the superior growth of plants on this medium was attributed to their high photosynthetic efficiency.     

旱区土壤无机氮素与春玉米根系时空分布对控释尿素输入的响应

以先玉698为供试材料,在等氮量(225 kg/hm²)条件下,以不施氮为对照(CK),设置UR (100%普通尿素,2/3基施,1/3小喇叭口期追施)、CRU1(1/3控释尿素+1/3普通尿素基施,1/3普通尿素小喇叭口期追施),CRU2(2/3控释尿素+1/3普通尿素一次基施)、CRU3(100%控释尿素基施)4种施氮模式,探究控释尿素输入对土壤氮素、玉米根系特性、氮素吸收及产量的影响。结果表明,相对于UR处理,CRU处理显著提升了春玉米生育中后期土壤硝态氮和铵态氮的含量,其中CRU2效果最明显。UR和CRU处理在不同时期对根系参数的影响不同,前期UR处理有利于根系的生长,花后CRU处理对0～80 cm土层根系长度及0～20 cm根重密度影响更大。通径分析进一步表明,玉米根长及根重密度的变化是增产的重要原因之一。CRU处理显著提升了玉米整个生育期内植株氮素含量及最终子粒产量。花后15 d,CRU处理较UR提高了子粒氮素含量,CRU处理间以CRU2最佳。CRU2处理子粒产量为14.65 t/hm²,分别较CK、UR、CRU1、CRU3提高32.70%、5.78%、1.52%、5.17%。在宁南山区CRU2处理能实现春玉米高产高效。     

基于牛粪垫料的有机无机复混肥对橘柚产量和品质的影响

为验证橘柚生长期追肥配施有机肥的可行性,根据橘柚膨果期需肥特性调配2种有机无机复混肥,采用大田实验,并设置多个施肥量,探讨有机无机复混肥用作追肥时不同施肥量对橘柚产量和品质的影响。结果表明,配方1和配方2均对橘柚产量无显著影响,显著降低了单果重、果皮重和果皮厚度,但增加了果肉比例,其中配方1施肥量为6.0 kg/株时果肉比例最高,达68.18%。配方1的5个施肥量均显著降低了橘柚果实总可溶性酸含量,显著增加了总可溶性糖、还原糖及抗坏血酸含量,提高糖酸比。而配方2的5个施肥量显著提高了橘柚的糖酸比,部分施肥量增加了总糖和还原糖含量。其中配方1施肥量与总糖和还原糖含量的关系可用三次回归方程和幂函数方程拟合。综上所述,橘柚生长期施用有机无机复混肥是可行的,其中配方1的肥效优于配方2,配方1推荐施肥量为4.8~6.0 kg/株为佳,而配方2推荐施肥量为3.6~4.5 kg/株为佳。     

Effects of Nitrogen Application Levels on Ammonia Volatilization and Nitrogen Utilization during Rice Growing Season

We conducted field trials of rice grown in sandy soil and clay soil to determine the effects of nitrogen application levels on the concentration of NH4+-N in surface water,loss of ammonia through volatilization from paddy fields,rice production,nitrogen-use efficiency,and nitrogen content in the soil profile.The concentration of NH4+-N in surface water and the amount of ammonia lost through volatilization increased with increasing nitrogen application level,and peaked at 1-3 d after nitrogen application.Less ammonia was lost via volatilization from clay soil than from sandy soil.The amounts of ammonia lost via volatilization after nitrogen application differed depending on the stage when it was applied,from the highest loss to the lowest:N application to promote tillering > the first N topdressing to promote panicle initiation(applied at the last 4-leaf stage) > basal fertilizer > the second N topdressing to promote panicle initiation(applied at the last 2-leaf stage).The total loss of ammonia via volatilization from clay soil was 10.49-87.06 kg/hm2,equivalent to 10.92%-21.76% of the nitrogen applied.The total loss of ammonia via volatilization from sandy soil was 11.32?102.43 kg/hm2,equivalent to 11.32%-25.61% of the nitrogen applied.The amount of ammonia lost via volatilization and the concentration of NH4+-N in surface water peaked simultaneously after nitrogen application;both showed maxima at the tillering stage with the ratio between them ranging from 23.76% to 33.65%.With the increase in nitrogen application level,rice production and nitrogen accumulation in plants increased,but nitrogen-use efficiency decreased.Rice production and nitrogen accumulation in plants were slightly higher in clay soil than in sandy soil.In the soil,the nitrogen content was the lowest at a depth of 40-50 cm.In any specific soil layer,the soil nitrogen content increased with increasing nitrogen application level,and the soil nitrogen content was higher in clay soil than in sandy soil.In terms of ammonia volatilization,the amount of ammonia lost via volatilization increased markedly when the nitrogen application level exceeded 250 kg/hm2 in the rice growing season.However,for rice production,a suitable nitrogen application level is approximately 300 kg/hm2.Therefore,taking the needs for high crop yields and environmental protection into account,the appropriate nitrogen application level was 250-300 kg/hm2 in these conditions.     

Retardation of shoot growth and promotion of tuber growth of potato plants by paclobutrazol

The relationship between shoot growth and tuber yield in potato plants (Solanum tuberosum L. cv. Russet Burbank) was studied under greenhouse conditions using paclobutrazol [(2R,3R + 2S,3S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(l,2-4-triazol-l-yl)-pentan-3-ol), PP333], a growth retardant. Concurrent with reduction of stem elongation by the application of paclobutrazol to base of the main stem was a decrease in the dry weight of the shoot and an increase in the dry weight of the tuber. The inhibitory effect of paclobutrazol on stem elongation was reversed by gibberellic acid A₃ (GA₃). Leaf content of raffinose sugar and chlorophyll increased upon paclobutrazol treatment.     

The response of Whitegrass [Cortaderia pilosa (D'Urv.) Hack.] to nitrogen nutrition

To investigate the potential for increasing Falkland Island Whitegrass [ Cortaderia pilosa (D'Urv.) Hack.] pasture production through application of nitrogen (N) fertilizer, two hydroponic experiments were conducted. First, 5 mg l^–1 N was supplied to plants as nitrate (NO₃^–), urea [CO (NH₂)₂], ammonium (NH₄⁺), or a nine parts NH₄⁺: one part NO₃^– mixture. At harvest, plants grown in a NO₃^– medium had about half the biomass of plants grown in a NH₄⁺ medium. In the second experiment plants were supplied with 1, 3, 10, 30 or 100 mg l^–1 NH₄⁺-N. Plants at 1 and 3 mg l^–1 N had the largest biomass of young root and the lowest shoot–root ratios. Leaf extension rate was low in the 1 mg l^–1 N treatment. Plants given 10 mg l^–1 N had the greatest proportion of green shoot material but little root growth; while those at 100 mg l^–1 N produced very little shoot and root biomass. Preferential assimilation of NH₄⁺-N and a low N requirement make Whitegrass well adapted to dominating vegetation on much of the Falkland Islands.     

Characterization of Vegetative Growth of a Supernodulating Soybean Genotype,Sakukei 4

Article

The supernodulating soybean cultivar Sakukei 4 was previously characterized by its superior ability to maintain a high leaf nitrogen (N) content and high photosynthetic rate. Despite these desirable traits, the growth performance of Sakukei 4 was inferior to that of its normally nodulating parental cultivar, Enrei. The physiological basis for the unique growth characteristics of Sakukei 4 remains unclear. The objective of the present study was to characterize in further detail thevegetative growth of Sakukei 4, particularly during the period before pod expansion. In the first experiment, the growth of Sakukei 4 was compared with that of its parental cultivar Enrei under various rates of N fertilizer. The dry weight of tops, roots and nodules of the plants grown at lower rates of N application was greater in Enrei than in Sakukei 4, but it was vice versa at higher rates of N application. The number and weight of nodules were far greater in Sakukei 4 than in Enrei at any rate of N application. These genotypic differences were significant on 39 days after sowing (DAS) and became greater at the flowering stage. In the second experiment, therefore, more detailed growth analysis was made during an earlier growth stage (DAS 31-46). During this period, relative growth rate (RGR), net assimilation rate (NAR) and leaf area ratio (LAR) were lower in Sakukei 4 than in Enrei and the related non-nodulating line En1282, whereas the leaf photosynthetic rate was higher in Sakukei 4 at all leaf positions. The dry-matter partitioning to each plant part excluding nodules was similar in all three genotypes. The rate of leaf expansion in Sakukei 4 during this period was significantly slower than that in the other genotypes. These results suggest that the inferior growth of Sakukei 4 prior to flowering is probably due to excessive dry-matter partitioning to nodules and depressed capability of leaf expansion and root growth, which might limit dry-matter production of the whole plant during pre-flowering stage.     

Kenaf (Hibiscus cannabinus L.) based substrates for the production of compact plants

Growth media based on whole-stem kenaf (Hibiscus cannabinus L.) and sand have been used to produce compact lettuce (Lactuca sativa L.) and pepper (Capsicum annuum L.) plants. Seeds were sown directly in kenaf-containing substrates and growth was recorded for up to 100 days after sowing. The presence of whole-stem kenaf (core and bark), even at a ratio of 10:90 (kenaf:sand), inhibited plant growth expressed as plant height, leaf number, and plant fresh and dry weight. When plants were subsequently transplanted to a kenaf-free substrate, growth continued at a similar rate to that of the control (sown and grown in peat and sand). The inhibitory effect of kenaf is located both in the core and bark, but is decreased by soaking the kenaf in NH₄NO₃ prior to use. A possible role for whole-stem kenaf (core and bark) in the production of compact plants is proposed.