中华猕猴桃胚乳植株后代的观察

对438株定植的中华猕猴桃胚乳培.养的试管苗,经四年的田间观察,并进行连续二年结果分析。与对照的母株相比,胚乳植株在株形、叶片大小、果实形态及果实的主要营养成分含量上都有较大的变化。同时还发现,由同一块愈伤组织诱导的胚乳试管苗后代中也有雌、雄性别的分化。胚乳植株后代的多样性,可为中华猕猴桃的选种及品种繁育提供丰富的材料。     

猕猴桃胚乳植株过氧化物酶同工酶的研究

猕猴桃是雌雄异株植物,由雌株胚乳培养的再生植株仍有雌、雄性别分化现象。对已开花结果的胚乳植株生物学特性观察表明,与对照母株相比,胚乳植株在株形、叶片大小、果实形状及果实的主要营养成分含量上都有较大的变化。为了探明整体水平变化与分子水平变化的关系,我们观察了有代表性的3株开花、挂果的猕猴桃胚乳再生雌株,1株胚乳变异雄株与对照父、     

猕猴桃胚乳培养中的胚胎发生

中华猕猴桃及硬毛猕猴桃的胚乳培养在MS+Zeatin 3 ppm+2,4-D0.5ppm+CH 400ppm的培养基上诱导产生愈伤组织,在MS+Zeatin 1 ppm+CH 400ppm的分化培养基上产生胚状体和长成完整小植株。细胞组织学观察表明,胚状体起源于愈伤组织内单个细胞,经原胚、球形胚、心形胚等阶段发育成苗。猕猴桃胚乳属于细胞型胚乳,它的这种胚状体起源于愈伤组织内单个细胞的发生方式,也不同于常见的胚状体发生于愈伤组织表面的方式。     

猕猴桃(Actinidia Lindl.)叶片与果实维生素C含量的相关性研究

以猕猴桃属中华猕猴桃（Actinidia chinensis）32个品种和1个种间杂交后代群体为研究对象,对猕猴桃属植物叶片与果实维生素C含量的相关性进行了研究。结果表明,在中华猕猴桃种内水平上,幼果与成熟果实的果肉维生素C含量间存在极显著的正相关关系;在种间杂交后代群体中成熟叶片和成熟果实的维生素C含量存在极显著正相关关系,为利用早期相关性状开展猕猴桃育种的可行性提供了理论依据。此外,对15个常见中华猕猴桃品种的果实维生素C含量进行了多重比较,为人工杂交时的亲本选择提供了依据。     

猕猴桃(Actinidia Lindl.)叶片与果实维生素C含量的相关性研究

以猕猴桃属中华猕猴桃(Actinidia chinensis)32个品种和1个种间杂交后代群体为研究对象,对猕猴桃属植物叶片与果实维生素C含量的相关性进行了研究。结果表明,在中华猕猴桃种内水平上,幼果与成熟果实的果肉维生素C含量间存在极显著的正相关关系;在种间杂交后代群体中成熟叶片和成熟果实的维生素C含量存在极显著正相关关系,为利用早期相关性状开展猕猴桃育种的可行性提供了理论依据。此外,对15个常见中华猕猴桃品种的果实维生素C含量进行了多重比较,为人工杂交时的亲本选择提供了依据。     

枸杞胚乳植株的诱导及染色体倍性观察

枸杞[Lycium chinense Mill.var.potaninii(Pojark)A.M.Lu]的未成熟胚乳接种在MS基本培养基上,并添加1毫克/升2,4-D和0.1毫克/升KT,诱导产生愈伤组织,其频率为23.8％。处于色变期的果实为胚乳培养的最适时期。胚在胚乳培养中不是必不可少的,但当有胚存在时可以提高胚乳愈伤组织的诱导频率。胚乳愈伤组织的继代培养对器官分化和植株再生没有明显影响。胚乳植株根尖细胞染色体数目不很一致,甚至有的植株同一根尖的不同细胞染色体数目也有不同。其中有三倍体(2n=3x=36),也有二倍体(2n=2x=24)和非整倍体的细胞,染色体数为9、18等,但从观察的15株胚乳苗来看,三倍体有11株,占73.3％,非三倍体的只有4株,占26.7％。     

猕猴桃优良株系果实生长发育规律研究

猕猴桃果实生长发育过程可分为三个时期。(1)迅速增长期:中华猕猴桃大约从4月中旬至6月上旬;美味猕猴桃大约从4月底或5月初至6月中下旬。(2)缓慢增长期:中华猕猴桃约自6月上旬至7月下旬;美味猕猴桃自6月下旬至7月下旬。(3)停滞增长期:中华猕猴桃从7月下旬至8月底或9月初;美味猕猴桃自8月上旬至9月上中旬。 中华猕猴桃优株果实可溶性固形物含量增长过程可分为四个阶段:(1)微升增长阶段,持续时间5周左右;(2)活跃增长阶段,持续2周左右;(3)迅速增长阶段,持续2周左右;(4)渐缓增长阶段。美味猕猴桃优株及绿果猕猴桃果实固形物含量增大变化的阶段性不明显。     

猕猴桃优良株系果实生长发育规律研究

猕猴桃果实生长发育过程可分为三个时期。(1)迅速增长期:中华猕猴桃大约从4月中旬至6月上旬;美味猕猴桃大约从4月底或5月初至6月中下旬。(2)缓慢增长期:中华猕猴桃约自6月上旬至7月下旬;美味猕猴桃自6月下旬至7月下旬。(3)停滞增长期:中华猕猴桃从7月下旬至8月底或9月初;美味猕猴桃自8月上旬至9月上中旬。 中华猕猴桃优株果实可溶性固形物含量增长过程可分为四个阶段:(1)微升增长阶段,持续时间5周左右;(2)活跃增长阶段,持续2周左右;(3)迅速增长阶段,持续2周左右;(4)渐缓增长阶段。美味猕猴桃优株及绿果猕猴桃果实固形物含量增大变化的阶段性不明显。     

机械振荡对猕猴桃试管苗根系发育的影响

目的:研究外界环境应力刺激对木本植物幼苗根系发育的生物学效应。方法:通过模拟机械振荡刺激中华猕猴桃的试管苗。结果:适度的机械振荡(频率2～3 Hz)可促进猕猴桃试管苗根系的生长发育,根系质膜的通透性降低,根尖活力以及根系总长、分根数等指标明显增加;但当振动强度超过一定值(4Hz)后,根系活力的增强效应就受到明显的抑制。结论:植物根系发育对外界应力刺激有较显著的双向效应;从细胞和分子生物学水平探讨了环境应力影响试管苗根系发育可能的内在机制。     

桂林种质圃中猕猴桃分类群的观察和测试

本项工作始于1980年冬,几年来共收集了猕猴桃物种和变种32个,定植于种质圃者27个种。另收集了中华猕猴桃、美味猕猴桃、金花猕猴桃等经济价值较大的优良类型28个。猕猴桃各分类群果实的营养成分差异很大,维生素C含量高的可达1013.98mg/100g果实,低的仅为8.8mg/100g果实;不同种和变种的种子发芽率为1.5—51.62％;幼苗形态特征、物候期以及植株长势等均有明显差异。     

Embryology in Trithuria submersa (Hydatellaceae) and relationships between embryo, endosperm, and perisperm in early-diverging flowering plants

? Premise of the study: Despite their highly reduced morphology, Hydatellaceae bear the unmistakable embryological signature of Nymphaeales, including a starch-rich maternal perisperm and a minute biparental endosperm and embryo. The co-occurrence of perisperm and endosperm in Nymphaeales and other lineages of flowering plants, and their respective functions during the course of seed development and embryo germination, remain enigmatic. ? Methods: Development of the embryo, endosperm, and perisperm was examined histologically from fertilization through germination in flowers and fruits of Trithuria submersa. ? Key results: The embryo of T. submersa initiates two cotyledons prior to seed maturity/dormancy, and their tips remain in contact with the endosperm throughout germination. The endosperm persists as a single layer of cells and serves as the interface between the embryo and the perisperm. The perisperm contains carbohydrates and proteins, and functions as the main storage tissue. The endosperm accumulates proteins and aleurone grains and functions as a transfer cell layer. ? Conclusions: In Nymphaeales, the multiple roles of a more typical endosperm have been separated into two different tissues and genetic entities: a maternal perisperm (nutrient acquisition, storage, mobilization) and a minute biparental endosperm (nutrient transfer to the embryo). The presence of perisperms among several other ancient lineages of angiosperms suggests a modest degree of developmental and functional lability for the nutrient storage tissue (perisperm or endosperm) within seeds during the early evolution of flowering plants. Finally, we examine the evolutionary developmental hypothesis that, contrary to longstanding assumptions, an embryo-nourishing perisperm along with a minute endosperm may represent the plesiomorphic condition for flowering plants.     

Endosperm culture: a novel method for triploid plant production

Triploid nature of endosperm is the characteristic feature of angiosperms and is formed as a result of triple fusion. Present review discusses the morphogenic response and production of triploid plantlets by endosperm culture. Both mature and immature endosperm used for culture initiation responded differently in cultures. A key factor for the induction of cell divisions in mature endosperm cultures is the initial association of embryo but immature endosperms proliferate independent of embryo. In almost all the parasitic angiosperms, endosperm shows a tendency of direct differentiation of organs without prior callusing, whereas in autotrophic taxa the endosperm usually forms callus tissue followed by differentiation of shoot buds, roots or embryos. The endosperm tissue often shows a high degree of chromosomal variations and polyploidy. Mitotic irregularities, chromosome bridges and laggards are the other important characteristics of endosperm tissues. Triploids are usually seed sterile and is undesirable for plants where seeds are commercially useful. However, in cases where seedlessness is employed to improve the quality of fruits as in banana, apple, citrus, grapes, papaya etc. the induction of triploid plants would be of immense use. Triploid plants have more vigorous vegetative growth than their diploid counterparts. Hence, in plants where the vegetative parts are economically useful, triploids are of good use. This review focuses on the progress achieved so far in endosperm culture to obtain triploid plants.     

Maternal control of nutrient allocation in plant seeds by genomic imprinting

Imprinted genes are commonly expressed in mammalian placentas and in plant seed endosperms, where they exhibit preferential uniparental allelic expression. In mammals, imprinted genes directly regulate placental function and nutrient distribution from mother to fetus; however, none of the >60 imprinted genes thus far reported in plants have been demonstrated to play an equivalent role in regulating the flow of resources to the embryo. Here we show that imprinted Maternally expressed gene1 (Meg1) in maize is both necessary and sufficient for the establishment and differentiation of the endosperm nutrient transfer cells located at the mother:seed interface. Consistent with these findings, Meg1 also regulates maternal nutrient uptake, sucrose partitioning, and seed biomass yield. In addition, we generated an imprinted and nonimprinted synthetic Meg1 ((syn)Meg1) dosage series whereby increased dosage and absence of imprinting both resulted in an unequal investment of maternal resources into the endosperm. These findings highlight dosage regulation by genomic imprinting as being critical for maintaining a balanced distribution of maternal nutrients to filial tissues in plants, as in mammals. However, unlike in mammals, Meg1 is a maternally expressed imprinted gene that surprisingly acts to promote rather than restrict nutrient allocation to the offspring.     

A model of triploid endosperm evolution driven by parent-offspring conflict

The parental investment in angiosperms comprises the endosperm, a nutrient reserve that is used during seed development. The endosperm contains genes from both parents. The most common endosperm form is the 3n Polygonum -type with more maternal genetic influence than paternal, i.e. with two maternal nuclei and one paternal nucleus. The evolutionary original state is thought to be a diploid endosperm with equal influence of the parents. We focus on the evolution of the triploid endosperm and show that a gene for triploid endosperm would have an initial advantage in a population of diploid endosperm type plants, and increase to fixation. We assume that endosperm amount is controlled by endosperm genes. Then a gene causing triploid endosperm will increase the influence of the mother plant on parental investment. The production of endosperm with two copies of the maternal genes will modify the inheritance of endosperm amount and cause an increased production of seeds.     

A subtilisin-like serine protease is required for epidermal surface formation in Arabidopsis embryos and juvenile plants.

The surfaces of land plants are covered with a cuticle that is essential for retention of water. Epidermal surfaces of Arabidopsis thaliana embryos and juvenile plants that were homozygous for abnormal leaf shape1 (ale1) mutations were defective, resulting in excessive water loss and organ fusion in young plants. In ale1 embryos, the cuticle was rudimentary and remnants of the endosperm remained attached to developing embryos. Juvenile plants had a similar abnormal cuticle. The ALE1 gene was isolated using a transposon-tagged allele ale1-1. The predicted ALE1 amino acid sequence was homologous to those of subtilisin-like serine proteases. The ALE1 gene was found to be expressed within certain endosperm cells adjacent to the embryo and within the young embryo. Expression was not detected after germination. Our results suggest that the putative protease ALE1 affects the formation of cuticle on embryos and juvenile plants and that an appropriate cuticle is required for separation of the endosperm from the embryo and for prevention of organ fusion.     

Arabidopsis haiku mutants reveal new controls of seed size by endosperm

In flowering plants, maternal seed integument encloses the embryo and the endosperm, which are both derived from double fertilization. Although the development of these three components must be coordinated, we have limited knowledge of mechanisms involved in such coordination. The endosperm may play a central role in these mechanisms as epigenetic modifications of endosperm development, via imbalance of dosage between maternal and paternal genomes, affecting both the embryo and the integument. To identify targets of such epigenetic controls, we designed a genetic screen in Arabidopsis for mutants that phenocopy the effects of dosage imbalance in the endosperm. The two mutants haiku 1 and haiku 2 produce seed of reduced size that resemble seed with maternal excess in the maternal/paternal dosage. Homozygous haiku seed develop into plants indistinguishable from wild type. Each mutation is sporophytic recessive, and double-mutant analysis suggests that both mutations affect the same genetic pathway. The endosperm of haiku mutants shows a premature arrest of increase in size that causes precocious cellularization of the syncytial endosperm. Reduction of seed size in haiku results from coordinated reduction of endosperm size, embryo proliferation, and cell elongation of the maternally derived integument. We present further evidence for a control of integument development mediated by endosperm-derived signals.     

四川藁本属植物果实和叶柄解剖学研究

对四川省藁本属5种植物的叶柄及果实进行了解剖研究,结果表明:藁本属植物的果实分为近两侧压扁和背腹压扁两种类型,背棱每棱槽内油管总数多为1~4个,合生面油管总数4~8个,在少数种间有一定的差异;胚乳背面微微隆起,腹面平直或微凹,如多管藁本,胚乳向内微凹;在蕨叶藁本中,胚乳占很大的比重,胚乳形状有很明显的个体差异.果实的压扁程度、油管特征、胚乳的形状等特征可以作为确定本属植物种间关系的依据.叶柄横切面类型多样,包括圆型、U型和V型,其中U型植物3种,占60%;近轴面除蕨叶藁本外,都具有沟槽;膜苞藁本和抽葶藁本中不具有髓腔,其他种类具髓腔,且大小、形状略有不同;横切面上维管束的数目多为5~14个,排列类型为圆型、U型、V型.以上叶柄等特征比较稳定,并且具有明显的种间差异,可以作为本属分类的重要依据.     

The effect of nitrogen and phosphorus deficiency on flavonol accumulation in plant tissues

The flavonol content of Arabidopsis thaliana and tomato seedlings was assessed in conditions of reduced nitrogen or phosphorus availability. In both systems, a significant inverse relationship was observed between nutrient availability and flavonol accumulation, with nitrogen limitation promoting the greatest increase in flavonols. A trial was established to determine the effects of decreased nitrogen and phosphorus availability on the flavonol content of leaf and fruit tissues of tomato plants (Lycopersicon esculentum cv. Chaser) in a commercial situation. Nutrients were supplied by a hydroponic system with nutrient regimes designed to provide the highest and lowest nitrogen and phosphorus levels with which it is possible to support plant growth and fruit set. Fruiting was abundant and tomato fruits were harvested at mature green, breaker and red stages of ripening; leaves were also harvested from the tops of the plants. All tissues were analysed for flavonol content using reversed‐phase high‐performance liquid chromatography. Flavonol accumulation in the leaves of mature tomato plants was found to increase significantly in response to nitrogen stress, whereas phosphorus deficiency did not elicit this response. Reduced nitrogen availability had no consistent effect on the flavonol content of tomato fruits. Phosphorus deficiency elicited an increase in flavonol content in early stages of ripening. Effects of nutrient stress on the flavonol content of tomato fruits were lost as ripening progressed. The findings suggest that nutrient status may be employed to manipulate the flavonol content of vegetative tissues but cannot be used to elevate the flavonol content of tomato fruit.