不同激素种类及浓度对红厚壳嫩枝扦插育苗的影响

以红厚壳（Calophyllum inophyllum）1年生嫩枝为扦插材料,探讨不同浓度梯度的萘乙酸（NAA）、吲哚丁酸（IBA）及生根粉1号（ABT）对插穗抽叶特性和生根特性的影响,并运用隶属函数值法对各处理组合的扦插效果进行综合评价。结果表明：与对照处理相比,不同激素种类及浓度处理显著影响嫩枝插穗的抽叶率、新叶数量、新叶面积等抽叶特性指标,以及生根率、偏根率、不定根数量、不定根体积、侧根数量和侧根长度等生根特性指标,但对宿叶率影响不显著。不同激素处理下嫩枝插穗的抽叶率和生根率分别为21.7%~66.7%和43.3%~98.3%,而对照处理的抽叶率和生根率均为0。基于隶属函数值法综合分析,激素处理对扦插效果的促进作用依次为NAA>ABT>IBA。NAA处理插穗的抽叶率和生根率均值为62.1%和95.4%,分别比ABT处理增加47.5%和30.2%,比IBA处理增加62.0%和57.9%。综合分析,红厚壳嫩枝扦插的最佳处理组合为1000 mg/L NAA,其抽叶率为61.7%,生根率为95.0%。     

Nursery Growth of Banana (Musa spp.) Plantlets Rooted on Auxin-free and Auxin-supplemented Media

Abstract

This paper describes the effects of auxin added to the culture medium on main and branch root formation of banana (Musa spp.) shoots and growth characters of the plantlet rooted on the medium with and without auxin. Banana shoots cultured in vitro on Murashige and Skoog medium supplemented with 2 μM 1-naphthylacetic acid (NAA), rooted earlier and also had more adventitious roots than those cultured on the medium without NAA. However, the adventitious roots formed on the medium without NAA showed more lateral branching. Plant height and number of leaves per plantlet in in vitro culture were not influenced by the addition of NAA but under nursery conditions, plantlets rooted without NAA showed better growth in terms of days to the appearance of new leaf, plant height and number of leaves per plant. This might be due to the presence of abundant lateral roots. Even though auxins are generally known to promote rooting, NAA inhibited the formation of lateral roots in Banana plants.     

Vegetative propagation of Grindelia chiloensis (Asteraceae)

Grindelia chiloensis (Asteraceae) is a shrub native to Patagonia, Argentina, in the process of domestication as a source of resin to complement rosin production by pines. Vegetative propagation to multiply selected genotypes has produced breakthroughs in the cultivation of new crops like jojoba (Simmondsia chinesis). The only available way to propagate Grindelia is by transplanting seedlings or direct seeding. Both alternatives rely on selected varieties, a process that takes several years in an open-pollinated, self-incompatible species. The objective of this study was to generate a protocol for the vegetative propagation of G. chiloensis. Two experiments were carried out to evaluate the effect of the mother plant, the source of the cutting (apical or basal), and the concentration of indole butyric acid (IBA) on rooting success and root and above-ground biomass accumulation. A third study was conducted to evaluate the field survival of the propagated plants. Stems (15 cm) were cut from several mother plants growing in the field and stored in plastic containers with ice for about 4 h. Two types of cuttings were prepared from each stem: apical (upper 6–8 nodes) and basal (lower 6–8 nodes). A commercially available IBA source (Hormex, rooting powder, Brooker Chemical, Hollywood, CA) was used at six concentrations (0.1, 0.3, 0.8, 1.6, 3.0, and 4.5%). The cuttings were dipped in water and in the plant regulator and planted into speedlings filled with peat moss, vermiculite and sand (1:1:1, v/v/v). The speedlings were placed under a mist system in a greenhouse at 25°C. Rooting success and root weight were evaluated 30 days after the experiments were started. The position of the cutting, the IBA concentration, and the mother plant affected rooting success. None of the basal cuttings rooted even with IBA treatment. For the apical cuttings, IBA concentrations between 0.1 and 1.6% resulted in more than 64% rooting and the largest root mass (P<0.01). The control cuttings (0% IBA) did not produce adventitious roots. Accessions differed on rooting success. Transplanting survival varied between 25 and 100% depending on the clone. Vegetative propagation will allow the multiplication of Grindelia clones selected for their productive superiority. Traits such as resin content and composition, and regrowth after harvest are important characteristics to select for.     

茶树插穗发根的解剖学和生物化学研究

通过对浙农12等七个无性系茶树品种扦插发根过程的显微切片观察和主要生化指标的测定,结果表明:茶树红棕色枝和绿色枝的不定根原基分别起源于木栓形成层和中柱鞘内侧的韧皮薄壁细胞。根据插穗基部解剖学和形态学特征的变化,茶树插穗不定根的形成过程可分为5个时期,即:根原基未分化期、根原基分化期、根原体分化前期、根原体分化后期和不定根形成期。用80ppm IBA 喷射母树两周后,个别品种的插穗在离开母树时已分化出不定根原体。插穗母叶内的淀粉和非蛋白氮高,母茎内的碳、氮比高,以及母叶内的蛋白氮含量低的品种,具有较强的发根能力。     

茶树扦插生根机理研究进展

茶树扦插的关键是不定根的形成过程,受到多种因素的共同调控,研究茶树生根机理对了解不定根形成及控制具有重要意义.本文介绍了国内外关于茶树不定根形成机理的解剖学、生理生化(植物激素、酶、营养物质)、分子生物学3个方面的研究进展.通过对茶树生根机理的综合研究,可以为加快茶树扦插生根速率和提高其成活率提供理论参考和技术支持.     

Optimizing the propagation of potato (Solanum tuberosum L.) by stem cuttings

Stem cuttings from potato plants are frequently used in multiplication programs for disease-free cultivars. The survival of these leafy cuttings is often very poor, and thus various techniques were investigated which were designed to increase rooting and cutting survival. Stock plants of cultivars “Caribe,” “Jemseg,” “Keswick,” “Russet Burbank,” “Sable,” “Sebago” and “Shepody” were grown in the greenhouse under long days. Promoting growth of the axillary shoots was successfully achieved by shading the shoot apex with aluminum foil. Trimming the outer leaves of the cuttings was deleterious to both survival and rooting. A rooting hormone improved root initiation and development, and the use of shade cloth or intermittent mist increased survival by reducing wilting. A rooting substrate of vermiculite: perlite (1:1) provided sufficient aeration, support and drainage for the cuttings. Antitranspirants sprayed on the stock plants prior to the excision of cuttings and also on the excised cuttings did not improve rooting or survival. The addition of activated charcoal (1% w:w) increased rooting of the cuttings and improved vigor of potted plants obtained from the cuttings.     

顶梢和功能叶对茶树全光照弥雾扦插快繁的影响研究

为进一步缩短茶树无性苗繁育周期,提高无性苗质量,本试验以3年生台茶12号（又名金萱）茶树嫩枝为扦插材料,采用全光照弥雾快繁育苗技术,研究了插穗顶梢保留与摘除、不保留成熟功能叶、保留1~3片成熟功能叶对茶树扦插苗根系和地上部生长的影响,并于扦插前对茶树嫩枝不同部位芽叶的相关生理生化指标进行了测定分析。结果表明,随叶片成熟度增加,可溶性糖和叶绿素含量呈递增趋势。净光合速率也随叶片成熟度的增加呈递增趋势,但以第2片成熟功能叶最高。可溶性蛋白含量随叶片成熟度的增加呈下降趋势,以顶部一芽一叶含量最高。带成熟功能叶插穗成活率和生根率均为100.00%,而不带成熟功能叶的一芽一叶插穗和一芽二叶插穗成活率和生根率均仅为5.00%和23.33%。根系生长以带3片功能叶留梢插穗最好,生根早且根量大,10βd内就有大量白色根点从茎段基部冒出,60%~70%茶苗形成二次根仅需37βd,且地上部新形成的成熟功能叶数也最多,但是新梢高度增长值小于保留顶梢带1片成熟功能叶插穗,基部茎粗增长值小于带2片成熟功能叶插穗。成熟功能叶片数的增加有利于根系生长发育,提高成活率和生根率;保留顶梢插穗的根系和地上部的生长优于去梢插穗。     

Genotypic Variation in Responses of Cassava (Manihot esculenta Crantz) to Drought and Rewatering: Root System Development

Abstract

Soil moisture condition is a major factor that affects root system development and thus, crop production. This study aimed to evaluate genotypic variations of cassava in root system structures and their responses to different soil moisture conditions by examining various root traits including production and elongation of adventitious roots and their laterals. Four pot experiments were conducted and different genotypes of various backgrounds were grown under well-watered, droughted, droughted to rewatered conditions. One field experiment was also conducted with selected genotypes till maturity. Results showed that substantial genotypic variations exist in root system structure, and the effects of the soil moistures were significant for most of the root traits. The principal component analysis (PCA) showed that the lateral root development mainly accounted for the variations in root system structure regardless of soil moisture conditions. The PCA on the differences between droughted and well-watered control, and droughted-rewatered and the control further indicated that the branching ability of adventitious roots was mainly responsible for the root system responses to drought as well as rewatering. Genotypic ranking in root system responses to drought was almost consistent among the pots and field experiments. Genotypicvariations in rooting depth were relatively small while those in horizontal spread were apparent in the field experiment.The ability to maintain adventitious root elongation under drought, resulting in relatively large horizontal spread of root system and to recover sharply from drought by lateral root branching may be related to good growth and yield performance under field.     

生长素、乙烯和温度对大豆不定根形成的影响

以主茎型大豆材料DN594和分枝型大豆材料CHARLESTON的下胚轴插条为研究对象,配制不同浓度IAA、乙烯利(乙烯释放剂)、IAA和乙烯利的混合溶液,采用浸泡的方法处理下胚轴插条,分析最佳处理浓度,然后利用荧光定量PCR的方法分析最佳浓度外源激素条件下温度对大豆不定根形成的生长素及乙烯调控相关基因表达变化的影响,为明确不同基因型大豆品种响应IAA和乙烯调控的表型及基因表达机制提供理论基础。结果表明:IAA和乙烯浓度梯度对大豆插条不定根形成呈现低浓度促进、高浓度抑制的规律,且不同基因型间处理效果差异明显;IAA和乙烯混合处理与单一激素处理差异明显,两个基因型间对IAA和乙烯两种激素混合处理敏感性不同;大豆不定根形成过程基因表达水平有差异,受温度影响;乙烯对IAA基因表达有明显的调控作用。     

Root System Development of Cassava and Sweetpotato during Early Growth Stage as Affected by High Root Zone Temperature

Abstract

Root zone temperature (RZT) is an important factor that affects the establishment of crops in the field. This study was conducted to determine the effect of high RZT on the root system development of cassava and sweetpotato and to assess the response of each root system component of cassava and sweetpotato to high RZTs. Cassava and sweetpotato are widely grown crops in soils that are prone to reach a high temperature especially during the dry season. The plant root system was the primary object of investigation in this study. Cassava and sweetpotato cuttings were grown in pots for 20 days in a growth chamber where two different soil temperature regimes were maintained : 40°C (high RZT) and 25°C (normal). High RZT significantly decreased the total length of the adventitious roots (ARs) and the number and total length of the first order lateral roots (LRs) in both cassava and sweetpotato. Reduction in these root growth parameters was greater in the latter than in the former. High RZT caused a marked increase in the number of the second order LRs in sweetpotato and tended to enhance the formation of the third order LRs. Under high RZT, in cassava, a higher proportion of the total number of ARs and the first order LRs, and thus, a greater fraction of the total root length came from the lower nodes of the cuttings that were buried deep in the soil at planting. In sweetpotato, a greater proportion of the total number and total length of the ARs and the first order LRs was observed in the nodes of the cuttings that were buried closer to the soil surface than those buried deeper. An opposite trend was evident in both cassava and sweetpotato grown under a normal RZT. In the screenhouse experiment where plants were grown for 12 days, root growth of cassava was significantly reduced by the high RZT that prevailed when the soil was not covered with mulch materials. The root development in the mulched soil was similar to that under normal RZT in the growth chamber.     

A Histological Evaluation of Adventitious Bud Formation in Cotyledons in Crotalaria juncea L.

Abstract

In Crotalaria juncea L., adventitious buds were formed in cotyledonary expiants cultured on 0.8% agar-solidified 1/2 MS basal medium containing B5 vitamins, 1.0 or 0.5 mg L^–1 NAA, 5.0 or 10.0 mg L^–1 BA and 3% sucrose. The frequency of adventitious bud formation was 30-45% in all combinations of NAA and BA. In histological observations, prominent mitotic figures were observed in several cells of the subepidermal palisade layers on the adaxial side of the expiants in contact with medium after 3 days of culture. Calli were formed within 6 days of culture. After 10 days of culture, numerous mature tracheary elements were produced at random in the proliferated regions, and cell divisions at the superficial region led to the formation of the meristematic structure. The shoot apex of the seedling produced numerous trichomes from superficial cells, but the adventitious bud formed on the cotyledon produced no trichomes. Initiation of the meristematic region in the expiant could be used as a target site for gene transfer experiments.     

温湿度变化对茶苗芽萌发基因表达的影响

利用数字基因表达谱技术研究了温湿度变化对秋插茶苗芽萌发基因表达的影响。通过保温棚处理日均温度提高约5.15℃,湿度提高5.10%,两者茶苗芽萌发具有明显差异。比较保温棚与对照芽的基因表达共筛选获得949个差异表达基因,其中503个基因受保温棚处理诱导上调表达,446个基因下调表达。对差异表达基因进行GO分类分析,在P值<0.01的情况下,有360个基因与14个GO分类匹配。其中7个GO分类与光合作用相关,P值最小的GO分类为光系统,其11个基因均表现为上调表达,说明高温高湿条件具有促进光合相关基因表达的作用。这些结果将为深入研究理解茶苗的生长机制及相关基因的克隆打下基础。     

Rapid multiplication of potatoes in the warm tropics: rooting and establishment of cuttings

Summary To expand potato production in developing countries using cuttings as a source of good quality planting material, requires simple low cost methods to root and establish them. Experiments at a warm tropical site in the Philippines, to determine appropriate methods, showed that simple media ranging from fine sand to clay subsoil mixed with rice hulls enabled rooting which was not improved by hormones. Nitrogen rich media, such as volcanic soil or compost with additional P, were best for developing cuttings into strong transplants but there were no major differences in root and shoot development from cuttings differing in size and age. Tuberizations was favored by increasing the number of nodes buried in the media. Low solar radiation of 7 MJ/m²/day enabled high cutting survival up to root initiation, after which higher radiation supported larger root and shoot production.     

二穗短柄草异戊烯基转移酶(IPT)编码基因的进化及功能分析

细胞分裂素(CTK)是一类重要的植物激素,主要作用是引起细胞分裂,诱导芽的形成和促进芽的生长。此外,CTK能够通过参与细胞分化来调控根分生组织大小,对根系生长有负调控作用。异戊烯基转移酶(IPT)是CTK合成过程中的一个关键的限速酶,在高等植物中均以多同源拷贝形式存在。为了探寻二穗短柄草IPT基因的进化起源,并阐明同源基因间潜在的功能分化及其在根系生长过程中的生物学功能,首先,对拟南芥及二穗短柄草的IPT基因进行了序列比对和进化分析,其次,利用荧光定量的方法对二穗短柄草中各IPT基因在不同组织不同发育阶段的转录水平进行了定量分析,最后,通过构建IPT基因RNAi的表达载体,对二穗短柄草中多个IPT基因的转录进行了沉默干扰。结果表明,tRNA-IPT可能代表了IPT祖先基因的功能,而且是ATP/ADP-IPT基因的供体基因。二穗短柄草各IPT基因具有一定的组织表达特异性,大部分ATP/ADP-IPTs处于转录不活跃状态,而tRNA-IPTs在根部和叶部的表达量都很高。因此,IPT基因在单子叶模式植物二穗短柄草中可能采用了不同于拟南芥的方式发挥功能,其主要的发挥功能形式是tRNA类型。二穗短柄草转IPT-RNAi植株表现出根系增强的表型,说明在根系早期发育阶段,二穗短柄草ATP/ADP型IPT基因起到了一定的调节作用。由于IPT基因在早熟禾亚科物种中较为保守,本研究可为增强麦类作物根系发育与提高抗旱性提供必要理论基础。     

Below-Ground Competition in a Maize/Groundnut Intercropping System as Affected by the Rooting Soil Layer

Abstract

A field experiment was conducted to compare the below-ground competition between the intercropped maize (Zea mays L.) and two groundnut (Arachis hypogea L.) cultivars regarding the rooting soil layer. Three rows of each cultivar of groundnut (cvs. X-14 and Red Spanish) were planted in between two rows of maize (cv. Badra) with inter-row spacing of 30 cm and intra-row spacing of 15 cm. Aluminium sheets, 10 cm in height, were placed as a root barrier between the maize and groundnut rows at three depths, i.e., 0-10 cm, 10-20 cm and 20-30 cm from the soil surface. In the control plot, the soil was trenched and refilled without the aluminium partitions. The ear and total biomass yield of the maize intercropped with X-14 with the root barrier at 0-10 cm depth, were significantly larger than those with the root barriers at the depths of 10-20 cm, 20-30 cm and the control. The yield (crop or total biomass) of the maize intercropped with Red Spanish was not significantly affected by the root barrier. In conclusion, groundnut cultivar X-14 was more suitable for intercropping with maize than Red Spanish, probably due to the differences in the rooting properties in the top soil layer.     

Responses of Rice Genotypes Carrying Different Dwarf Genes to Fusarium moniliforme and Gibberellic Acid

Abstract

A total of 32 rice genotypes carrying different dwarf or semi-dwarf genes were inoculated with the fungus Fusarium moniliforme Sheldon or treated with 50 mg l-¹ GA₃ in order to select resources resistant to rice bakanae disease from the dwarf materials. The length of the elongated seedlings was measured, and the percentage of death of the seedlings after transplanting to field was also counted. A significant correlation was found between the length of the seedling treated with GA₃ and disease injury by bakanae fungus. Rice materials carrying dwarf gene such as sd1 were not only sensitivity to GA₃ but also susceptive to rice bakanae disease. Materials carrying dwarf gene d1 were insensitive to GA₃ but susceptive to bakanae. On the other hand, all materials carrying d29, sd6 or sdq(t) genes showed resistance to bakanae. The present study indicated that dwarf and semi-dwarf rice materials might be useful resources for improvement of bakanae resistance in rice breeding programs.     

Rooting Nodes of Deep Roots in Rice and Maize Grown in a Long Tube

Summary

Penetration of the roots deep into soil layer (deep roots) may alleviate growth inhibition under various soil stress conditions. In this study, the nodes from which deep roots had emerged were examined at the heading stage in rice and maize grown in a 2 m long tube. The effect of soil mechanical stress on the rooting nodes of deep roots was also examined. The roots that emerged in a relatively early growth stage, that is, the roots from coleoptilar, 1st and 2nd node in rice, and the seminal root and roots from the coleoptilar, 1st and 2nd nodes in maize, penetrated into the deep soil layer. The node which produced the highest number of deep roots was the 1st node in rice and the coleoptilar node in maize. Seminal root of rice and seminal adventitious roots of maize did not penetrate into the deep soil layer although they emerged at an early growth stage. In the rice root system, the nodal roots, emerged from the upper portion of the node, tended to penetrate deeper than the nodal roots emerged from the lower portion of the same node. Soil compaction did not affect these tendencies.     

野生二粒小麦NBS-LRR类抗病基因家族的鉴定及其表达分析

野生二粒小麦(Triticum dicoccoides L,2n=4x=28,AABB)是普通小麦遗传改良的重要种质和基因库。抗病基因(resistance gene,R基因)是植物体内广泛存在的抗性基因,通常具有NBS(nucleotide-binding site)和LRR(leucine-rich-repeat)结构域,属于NBS-LRR家族,在植物抗病和免疫过程中具有重要作用。为挖掘和利用野生二粒小麦基因组中的R基因,基于最新发布的野生二粒小麦参考基因组数据,利用生物信息分析手段,在全基因组水平上对其NBS-LRR类R基因家族进行鉴定。结果共鉴定到429个可信度较高的NBS-LRR类R基因,其中N亚家族66个,CNL亚家族205个,NL亚家族76个,CN亚家族79个,PN亚家族3个;进一步对NL亚家族R基因进行分析,发现76个NL亚家族基因在所有染色体上均有分布,并且以成簇方式存在,包含20个保守域,且在N端高度保守;表达模式分析发现,它们在花、叶片和根中的表达量较高;最后,随机选择4个NL类R基因,发现在白粉菌诱导后均上调表达。本研究为进一步挖掘和利用野生二粒小麦NBS-LRR类抗病基因奠定了基础。     

Elongation Ability of African Floating Rice (Oryza glaberrima Steud.)

Summary

The effect of fluctuation in soil moisture on the root development of sweetpotato was studied during its establishment period, i.e., from planting to about one month after planting. The number of leaves, shoot dry weight and vine length were suppressed significantly by deficient moisture but the same were markedly increased by excessive moisture regardless of the time of occurrence relative to the initial development of the plant. In terms of its roots, the number and total length of the root system components were either increased or decreased depending upon the soil moisture regime in which they were subjected immediately prior to the time of sampling. Deficient soil moisture reduced the number and total length of the root system components while excessive moisture caused notable stimulation. Continuous exposure to normal soil moisture caused substantial reduction in the number of adventitious roots and consequent depression in total length but this could be attributed to sink competition among adventitious roots. Under fluctuating soil moisture, normal moisture content appeared to restore the aberrant development of the roots caused by deficient or excessive levels. The suppressed formation and elongation of the root system components under deficient soil moisture was alleviated when the soil moisture condition was changed to normal. On the other hand, the stimulated root formation and elongation in the excessive moisture was abated when the normal soil moisture condition prevailed afterwards. The result was the opposite when the soil moisture condition was reversed, i.e., normal then followed by either deficient or excessive soil moisture.     

小麦品种东农冬麦2号根中TaEXPA7部分同源基因的克隆及表达特性分析

膨胀素(expansin)是植物生长发育过程中诱导细胞壁松弛和伸展的蛋白,包括EXPA、EXPB、EXLA、EXLB四个基因家族,对植物根系的形成及快速发育具有重要作用。本试验以寒地冬小麦品种东农冬麦2号两叶一心期的根为材料,克隆了TaEXPA7基因的3个CDS全长,其氨基酸序列同源性较高,仅信号肽处有两个氨基酸不同,其核酸序列长度均为777bp,编码258个氨基酸,分别命名为TaEXPA7-A、TaEXPA7-B、TaEXPA7-D,且分别定位于2AL、2BL、2DL染色体。蛋白均含有DPBB-1和Pollen-allerg-1两个保守结构域,分子量为27 670.74Da,等电点为8.09,均为疏水性蛋白;与节节麦、二穗短柄草的相似性分别为99%和92%。采用两叶一心期的根进行qRT-PCR分析发现,TaEXPA7-A/B/D三个基因在根尖中的表达量均较高,伸长区和成熟区次之;对冬小麦根进行低温、干旱和激素处理后,这三个基因均下调表达,并且TaEXPA7-B基因的相对表达量较高,TaEXPA7-D的相对表达量较低。由此可见,多倍体小麦不同染色体上的基因在应对不同环境胁迫时,表达以及应答模式存在差异,并且在不同的环境胁迫下,发挥主导作用的染色体也存在差异;此外,该基因在根中的表达可能与低温、干旱以及外源激素的胁迫有一定的关系,可能是促进根系生长的重要基因。