Fruit Development in Trillium : Dependence on Stem Carbohydrate Reserves

Leaves are the main source of carbon for fruit maturation in most species. However, in plants seeing contrasting light conditions such as some spring plants, carbon fixed during the spring could be used to support fruit development in the summer, when photosynthetic rates are low. We monitored carbohydrate content in the rhizome (a perennating organ) and the aboveground stem of trillium (Trillium erectum) over the entire growing season (May–November). At the beginning of the fruiting stage, stems carrying a developing fruit were harvested, their leaves were removed, and the leafless stems were maintained in aqueous solution under controlled conditions up to full fruit maturation. These experiments showed that stem carbohydrate content was sufficient to support fruit development in the absence of leaves and rhizome. This is the first reported case, to our knowledge, of complete fruit development sustained only by a temporary carbohydrate reservoir. This carbohydrate accumulation in the stem during the spring enables the plant to make better use of the high irradiances occurring at that time. Many other species might establish short-term carbohydrate reservoirs in response to seasonal changes in growing conditions.     

Factors affecting the distribution of cadmium,copper and lead and their effect upon yield and zinc content in bush beans (Phaseolus vulgaris L.)

Summary Concentrations of Cd, Pb and Cu in the roots, stems and leaves of bulgarian bush beans (Phaseolus vulgaris L.) were determined for plants grown in various soils of increasing levels of contamination of these metals. Most of each heavy metal absorbed by plants was retained in roots. Concentrations of Cd, Pb and Cu in roots increased in response to soil concentrations, whereas, in stems, only Cd and Pb concentrations increased and Cu concentration was relatively constant. It is thought that Cu transport to the stele was metabolically controlled, whereas Cd and Pb reached the stem by leakage across non suberised areas of the endodermis. Uptake of heavy metals was associated with a decrease in zinc content in plants and a decrease in yield. By regression analysis decrease in both zinc content and plant yield could be best related to Cd content in stems. Possible reasons for these effects are discussed.     

Growth characteristics of Sanguinaria canadensis L. Cell suspensions and immobilized cultures for production of benzophenanthridine alkaloids

Summary Sanguinaria canadensis L. plants were harvested from a local forest and calli were initiated from leaf explants. The production of benzophenanthridine alkaloids (i.e. sanguinarine, sanguilutine, sanguirubine, chelerythrine, chelilutine and chelirubine) by S. canadensis cell grown in modified B5 and IM2 media was compared to the alkaloid content of rhizomes. Sanguinarine accounted for approximately 80% of the total alkaloid content of cultured cells (1.3%,g g^–1) while sanguinarine and sanguirubine accounted for 70% of rhizome alkaloids (9.0%, g g^–1). Sanguinarine, chelirubine and chererythrine were the only known alkaloids detected in cultured S. canadensis cells. Maximum alkaloid production of cultures performed using B5 medium, containing half the original nitrate concentration, was observed following extracellular nitrate and sugar depletion. The scale-up of this culture was successfully performed in a 2-1 immobilization bioreactor. The consumption of sugar and nitrate as well as the oxygen (OTR) and carbon dioxide (CTR) transfer rates of the immobilized cell culture were monitored for 15 days. The maximum sugar and nitrate consumption rates were 1.8 g l^–1 per day and 2.3 mm per day respectively. The maximum OTR and CTR of the immobilized cell culture were 0.8 mmol O₂ l^–1 h^–1 and 0.95 mmol CO₂ l^–1 h^–1 respectively. The sanguinarine yield of this culture reached 1.0% based on biomass dry weight (g g^–1 dw) by day 15.     

The effect of assimilate supply on fruit growth and hormone levels in tomato plants

Rates of dry matter accumulation and contents of starch, sugars and abscisic acid (ABA) of tomato fruits differed significantly during development at three positions (proximal, middle and distal) on a truss. Proximal fruits, which accumulated dry matter most rapidly during early development, generally had least ABA (per g DW).Partial defoliation reduced carbon accumulation by all fruits but increased ABA, especially in distal fruit, and indoleacetic acid (IAA), particularly in proximal fruits. The ABA content of leaves in partially defoliated plants was similar to that of leaves on non-defoliated plants.Removal of distal fruits on a truss enhanced carbon movement to the remaining proximal fruits and also increased their ABA content early in development but did not affect their IAA content. On the other hand, when proximal fruit were removed there was no large or lasting increased accumulation of carbon by the remaining distal fruits and they contained less ABA and IAA than fruits on plants without fruit thinning. Leaf carbon and ABA levels showed no marked trend in response to fruit thinning.The amount of carbon in the stems was increased by fruit thinning but decreased by partial defoliation.The possible roles of ABA and IAA in regulating fruit growth are discussed.Part of this work has been presented to a Symposium on Phloem loading and related processes at Bad Grund/Oberhar, W. Germany, July 1979.     

Isolation of a cDNA clone (PcSrp) encoding serine-rich-protein from Porteresia coarctata T. and its expression in yeast and finger millet (Eleusine coracana L.) affording salt tolerance

A 1.4 Kb cDNA clone encoding a serine-rich protein has been isolated from the cDNA library of salt stressed roots of Porteresia coarctata, and designated as P. coarctata serine-rich-protein (PcSrp) encoding gene. Northern analysis and in situ mRNA hybridization revealed the expression of PcSrp in the salt stressed roots and rhizome of P. coarctata. However, no such expression was seen in the salt stressed leaves and in the unstressed tissues of root, rhizome and leaf, indicating that PcSrp is under the control of a salt-inducible tissue-specific promoter. In yeast, the PcSrp conferred increased NaCl tolerance, implicating its role in salinity tolerance at cellular level. Further, PcSrp was cloned downstream to rice Actin-1 promoter and introduced into finger millet through particle-inflow-gun method. Transgenic plants expressing PcSrp were able to grow to maturity and set seed under 250 mM NaCl stress. The untransformed control plants by contrast failed to survive under similar salt stress. The stressed roots of transgenic plants invariably accumulated higher Na⁺ and K⁺ ion contents compared to roots of untransformed plants; whereas, shoots of transgenics accumulated lower levels of both the ions than that of untransformed plants under identical stress, clearly suggesting the involvement of PcSrp in ion homeostasis contributing to salt tolerance.     

Enhanced yield of tomato in response to 2-(3,4-dichlorophenoxy)triethylamine (DCPTA)

Application of the bioregulator, 2-(3,4-dichlorophenoxy)triethylamine (DCPTA) to tomato (Lycopersicon esculentum Mill. cv. Pixie) significantly increased the vegetative growth and fruit-yield productivities of mature plants. Compared with controls, application of 30 M (10 ppm) DCPTA as a pre-germination seed treatment increased the mean relative growth rates of leaves, stems, and roots, 37%, 16%, and 20%, respectively, during exponential growth. At fruit harvest, the dry weights of leaves, stems, and roots, and the harvestable yield of 30 M DCPTA-treated plants were doubled when compared with controls. Increases in both the total fruit number per plant and the size of individual fruits contributed to the improved yield of 30 M DCPTA-treated plants. The total soluble solids contents of mature fruits harvested from 30 M DCPTA-treated plants were increased 24%, and the lycopene and beta-carotene contents were doubled as compared with controls. These results indicate that DCPTA treatment does not adversely affect the balanced partitioning of photoassimilate to vegetative and reproductive sinks in tomato.     

长期淹水对河竹鞭根养分化学计量特征的影响

以长期淹水环境下能生长更新的河竹为材料,调查测定了人工喷灌供水(CK)、淹水6个月(TR)的河竹一年生竹鞭的根生物量和主要养分元素含量,分析长期淹水对河竹鞭根养分化学计量特征的影响,为河竹在水湿地和消落带植被恢复中的应用提供理论依据。结果显示:(1)与CK相比,TR处理下的河竹土中根的N、P、Mg和Ca含量显著降低,Fe含量显著升高,且N、K和Ca含量显著低于TR处理下水中根的含量,而Fe含量显著高于水中根。(2)TR处理的河竹土中根的C/N、C/P、C/K和P/K较CK显著升高,且C/K、N/K和P/K显著高于TR处理的水中根。(3)TR处理的河竹水中根的C-N、C-P、N-P均呈极显著正相关关系,土中根的C-P、C-K、P-K均呈极显著正相关关系;CK河竹土中根的C-P、C-K呈极显著正相关关系,且N-P显著相关;从相关系数看,TR处理下土中根的C-N、N-P和N-K相关性减弱,C-P、C-K和P-K相关性增强,而C-N、C-P、N-P和N-K相关性较水中根减弱,C-K和P-K相关性较水中根增强。(4)TR处理下鞭根生物量和C、N、P、K、Mg、Ca积累量较CK分别显著降低19.46%、42.04%、36.55%、41.39%、60.06%和38.46%,而Fe积累量显著升高,为CK的5.5倍;TR处理下土中根养分积累量显著高于水中根。研究表明,长期淹水虽阻碍了河竹鞭根的养分平衡吸收,但能够提高养分利用效率,并且土中根和水中根具有克隆分工特征,水中根主要起到氧气吸收应对缺氧环境胁迫的功能,是河竹适应长期淹水环境的重要生态对策。     

Importance of seed Zn content for wheat growth on Zn-deficient soil

Eggplants (Solanum melongena L. cv. Bonica) were grown in a glasshouse during summer under natural light with one unbranched shoot or one shoot with 3 to 4 branches and with or without fruit in quartz sand buffered and not buffered with 0.5% CaCO₃ (w : v), respectively. Nutrient solutions supplied contained nitrate or ammonium as the sole nitrogen source. Compared with nutrient solutions containing nitrate (10 mM), solutions containing ammonium (10 mM) caused a decrease in net photosynthesis of eggplants during early stages of vegetative growth when grown in quartz sand not buffered with CaCO₃. The decrease was not observed before leaves showed interveinal chlorosis. In contrast, net photosynthesis after bloom at first increased more rapidly in eggplants supplied with ammonium than with nitrate nitrogen. However, even in this case, net photosynthesis decreased four weeks later when ammonium nutrition was continued. The decrease was accompanied by epinasty and interveinal chlorosis on the lower leaves and later by severe wilting, leaf drop, stem lesions, and hampered growth of stems, roots, and fruits. These symptoms appeared later on plants not bearing fruits than on plants bearing fruits. If nutrient solutions containing increasing concentrations of ammonium (0.5–30 mM) were supplied after the time of first fruit ripening, shoot growth and set of later flowers and fruits were promoted. In contrast, vegetative growth and reproduction was only slightly affected by increasing the concentration of nitrate in the nutrient solutions. In quartz sand buffered with CaCO₃ ammonium nutrition caused deleterious effects only under low light conditions (shade) and on young plants during rapid fruit growth. If eggplants were supplied with ammonium nitrogen before bloom, vegetative growth was promoted, and set of flowers and fruit occurred earlier than on plants supplied with nitrate. Furthermore, the number of flowers and fruit yield increased. These effects of ammonium nutrition were more pronounced when plants were grown with branched shoots than with unbranched shoots. The results indicate that vegetative and reproductive growth of eggplants may be manipulated without causing injury to the plants by supplying ammonium nitrogen as long as the age of the plants, carbohydrate reserves of the roots, quantity of ammonium nitrogen supplied, and pH of the growth medium are favourable. T W Rufty Section editor     

香蕉幼苗三类有机小分子溶质对尖孢镰刀菌侵染的生理响应

为阐明香蕉枯萎病发病机制,研究了尖孢镰刀菌侵染后,香蕉植株中几种对尖孢镰刀菌生长有显著作用的物质(氨基酸、有机羧酸、酚酸)种类和含量的变化。结果表明:(1)病原菌侵染后,伤害逐渐加剧,株高和生物量显著下降。(2)病原菌侵染后,叶片氨基酸总量显著升高,其中丝氨酸、缬氨酸、组氨酸、异亮氨酸和亮氨酸增幅较大,病原菌侵染16 d,其含量分别为侵染前的7.1、6.2、4.4、3.5和2.3倍;而根氨基酸总量开始显著降低,差异逐渐变小。(3)叶片有机羧酸酸含量在病原菌侵染后显著增加,而在根中显著降低。侵染植株叶片中草酸、柠檬酸、苹果酸、琥珀酸和延胡索酸含量分别是未侵染植株叶片的2.6、1.6、1.9、1.8和2.3倍;根中草酸、柠檬酸、苹果酸、琥珀酸和延胡索酸含量分别是未侵染植株的81%、42%、44%、28%和59%。(4)病原菌侵染后,植株叶片和根中酚酸含量都显著升高。叶片中阿魏酸、肉桂酸和水杨酸含量分别是未侵染叶片的2.9、1.7和2.9倍;而根中对羟基苯甲酸和丁香酸含量分别是未侵染根的4.3和1.5倍。研究结果表明,尖孢镰刀菌侵染后,植物与病原菌的相互作用使得植物体内抑菌物质和促菌物质都会相应的增加,植株对病害有一定的抗性,但促菌物质种类和含量较高最终使得感病植株发病。     

Physiological responses of <Emphasis Type="Italic">Lupinus luteus</Emphasis> to different copper concentrations

Yellow lupin (Lupinus luteus L.) plants were grown in hydroponic solution for 15 d under different copper concentrations (0.1, 0.5, 1.0, 10, 25 and 50 μM). With increasing Cu concentration total biomass was not affected, leaf area slightly decreased, while chlorophyll content decreased considerably. Cu content increased significantly both in roots and in leaves, but the contents of other ions were only slightly affected at the highest Cu concentration (Mn content decreased both in roots and in leaves, P content decreased only in leaves and Zn content increased in roots). Superoxide dismutase (SOD) activity increased up to day 7 after copper application. Peroxidase (GPOD) and polyphenol oxidase (PPO) activities also increased, while catalase (CAT) activity remained constant.     

Correlation of the cytotoxic activity of four different alkaloids, from Chelidonium majus (greater celandine), with their DNA intercalating properties and ability to induce breaks in the DNA of NK/Ly murine lymphoma cells

The purpose of this study was to examine the relationship between the DNA intercalating characteristics and the DNA damaging capacity of four alkaloids extracted from Chelidonium majus L, as well as their toxicity towards murine NK/Ly lymphoma cells. Chelerythrine, sanguinarine and coptisine were found to be intercalated into the DNA isolated from NK/Ly cells, meanwhile, chelidonine exhibited no affinity to DNA. Sanguinarine exhibited the greatest toxicity toward NK/Ly cells, and the toxicity of the other three decreased in descending order: chelerythrine, coptisine and chelidonine. Chelerythrine and sanguinarine caused DNA damage, illustrated by the formation of comets of the third class. Coptisine was less toxic than chelerythrine and sanguinarine, and affected the formation the same class of comets in higher concentration. The quantity of comets induced by chelidonine were negligible, a finding consistent with its inability to intercalate into DNA structure. The ability of four main alkaloids of Chelidonium majus L., to intercalate into DNA isolated from murine NK/Ly lymphoma cells, correlated with their ability to induce breaks in cellular DNA and with their toxic effect towards those cells.     

Distribution of assimilate during the flush cycle of growth in Theobroma cacao L.

The growth of the shoot and roots of seedling plants of cocoa (Theobroma cacao L.) under constant glasshouse conditions showed a rhythmic cycle, with the maximum growth stages of each alternating in a regular sequence. When the growth cycle of the shoot was upset by removing all new leaves immediately after unfolding, the roots showed a high constant growth rate during this period, suggesting that normally the rapidly expanding leaves exert an inhibitory influence on the roots. Conversely removal of portions of the root delayed the production of new leaves in the shoot. The level of soluble and starch carbohydrate in the mature leaves, roots and stem declined during the period of expansion of the flush leaves, but accumulated again at the end of the leaf expansion stage. It is likely that this reserve carbohydrate was remobilised and translocated to the flush leaves during their period of expansion. A large proportion of newly formed photoassimilate, as shown by the distribution of ¹⁴C radioactivity from different source leaves, was also translocated to the young leaves during expansion. The large sink created by these leaves may cause photoassimilate and reserve carbohydrate to be diverted from the roots, thereby inhibiting root growth during the stage of leaf expansion. It is suggested that the rhythmic leaf production at the apex may control the growth cycle of the roots.     

Medicinal plants resources of Western Himalayan Palas Valley,Indus Kohistan,Pakistan: Their uses and degrees of risk of extinction

Present study was intended with the aim to document the pre-existence traditional knowledge and ethnomedicinal uses of plant species in the Palas valley. Data were collected during 2015–2016 to explore plants resource, their utilization and documentation of the indigenous knowledge. The current study reported a total of 65 medicinal plant species of 57 genera belonging to 40 families. Among 65 species, the leading parts were leaves (15) followed by fruits (12), stem (6) and berries (1), medicinally significant while, 13 plant species are medicinally important for rhizome, 4 for root, 4 for seed, 4 for bark and 1 each for resin. Similarly, thirteen species were used as a whole while twelve species as partial for medicinal purpose. Further, it is concluded that every part of plants such as bulb, rhizome, roots, barks, leaves, flowers, fruit and seed were used for various ailments. Moreover, among 65 plants species, 09 species are threatened and placed into Endangered (EN) and Least Concern (LC) categories of IUCN. The recorded data are very useful and reflects the significance of the Palas valley as medicinal plants resource area.     

In vitro propagation of Alstroemeria ‘Alsaan’

Plantlets were regenerated from Alstroemeria Alsaan rhizome tips cultured in vitro on solid and liquid media based on Murashige and Skoog salt formulation. The quality of the cultures was superior when intact rather than longitudinally sliced rhizome tips were used as explants and when a temperature of 8°C rather than 22°C was used at the initiation stage. More roots were produced on rhizome tips containing a rhizome apical meristem than on rhizome sections lacking such a meristem. Most (90%) of the rooted plantlets were successfully acclimatized and developed into true-to-type flowering plants.     

Lacunal allocation and gas transport capacity in the salt marsh grass Spartina alterniflora

Summary Lacunal allocation as the fraction of the total cross sectional area of leaves, stem bases, rhizomes, and roots was determined in both tall and short growth forms of Spartina alterniflora collected from natural monospecific stands. The results indicate that in both growth forms lacunal allocation is greater in stem bases and rhizomes than in leaves and roots and that tall form plants allocate more of their stem and rhizome to lacunae than short form plants.Measurements made in natural stands of Spartina alterniflora suggest that total lacunal area of the stem base increases with increasing stem diameter and that stem diameter increases with increasing plant height and above-ground biomass. However, the fraction of cross section allocated to lacunae was relatively constant and increased only with the formation of a central lacuna.Experimental manipulations of surface and subsurface water exchange were carried out to test the influence of flooding regime on aerenchyma formation. No significant differences in lacunal allocation were detected between plants grown in flooded (reduced) and drained (oxidized) sediments in either laboratory or field experiments. While aerenchyma formation in Spartina alterniflora may be an adaptation to soil waterlogging/anoxia, our results suggest that lacunal formation is maximized as a normal part of development with allocation constrained structurally by the size of plants in highly organic New England and Mid-Atlantic marshes.The cross sectional area of aerenchyma for gas transport was found to be related to the growth of Spartina alterniflora with stands of short form Spartina alterniflora exhibiting a lower specific gas transport capacity (lacunal area per unit below ground biomass) than tall form plants despite having a similar below-ground biomass supported by a 10 fold higher culm density. The increased specific gas transport capacity in tall vs. short plants may provide a new mechanism to explain the better aeration, higher nutrient uptake rates and lower frequency of anaerobic respiration in roots of tall vs. short Spartina alterniflora.     

Variation of bioactive secondary metabolites in <Emphasis Type="Italic">Hypericum origanifolium</Emphasis> during its phenological cycle

The genus Hypericum has received considerable interest from scientists, as it contains the variety of structurally diverse natural products which possess a wide array of biological properties. The present study was conducted to determine ontogenetic and morphogenetic variation of hypericin, chlorogenic acid and flavonoids, as rutin, hyperoside, apigenin-7-O-glucoside, quercitrin and quercetin content in Hypericum origanifolium growing in Turkey. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting and mature fruiting stages and dissected into stem, leaf and reproductive tissues and assayed for bioactive compounds by HPLC method. Hypericin, quercetin and quercitrin content in whole plant increased during course of ontogenesis and the highest level was reached in blooming stage. On the contrary, hyperoside content of whole plant decreased linearly with advancing of development stages and the highest level was observed at vegetative stage. Plants produced similar amount of chlorogenic acid at all stages of plant phenology except for mature fruiting at which the amount of this compound was decreased sharply. Among different tissues, reproductive parts accumulated the highest level of hypericin, quercetin and quercitrin, however, leaves produced substantially higher amount of chlorogenic acid and hyperoside. Rutin and apigenin-7-O-glucoside were detectable in all tissues only during fruit maturation. The presence and variation of these bioactive substances in H. origanifolium were reported for the first time.     

Expression of a deregulated tobacco nitrate reductase gene in potato increases biomass production and decreases nitrate concentration in all organs

We investigated the physiological consequences for nitrogen metabolism and growth of the deregulated expression of an N-terminal-deleted tobacco nitrate reductase in two lines of potato (Solanum tuberosum L. cv Safrane). The transgenic plants showed a higher biomass accumulation, especially in tubers, but a constant nitrogen content per plant. This implies that the transformed lines had a reduced nitrogen concentration per unit of dry weight. A severe reduction in nitrate concentrations was also observed in all organs, but was more apparent in tubers where nitrate was almost undetectable in the transgenic lines. In leaves and roots, but not tubers, this nitrate decrease was accompanied by a statistically significant increase in the level of malate, which acts as a counter-anion for nitrate reduction. Apart from glutamine in tubers, no major changes in amino acid concentration were seen in leaves, roots or tubers. We conclude that enhancement of nitrate reduction rate leads to higher biomass production, probably by allowing a better allocation of N-resources to photosynthesis and C-metabolism.Abbreviations DAP Days after planting - Gln Glutamine - NR Nitrate reductase - WT Wild type     

Effect of soil cadmium application and pH on growth and cadmium accumulation in roots, leaves and fruit of strawberry plants (Fragaria × ananassa Duch.)

Three strawberry (Fragaria × ananassa Duch.) cultivars Rainier, Totem and Selva were grown under greenhouse conditions in a Parkhill sandy loam soil with a background DTPA-extractable Cd concentration of 0.18 mg kg^-1 and a pH of 5.1. Experimental treatments included combinations of 4 Cd applications (0, 15, 30 and 60 mg Cd kg^-1 soil) applied as CdSO₄ and 2 soil pH values 5.1 and 6.8. Both the application of Cd and pH of the soil significantly affected plant growth, yield and Cd accumulation in plant tissue anf fruit. Although roots accumulated the highest concentrations of Cd of all plant parts investigated, increased soil Cd application reduced leaf weight more than root weight. In general, yield of strawberries was decreased by an increase in amount of soil-applied Cd, however the yield response varied among cultivars. At 60 mg Cd kg^-1 soil, yield of Rainier cultivar was reduced to 17.6% of control plants. Over 90% of total Cd taken up by plants grown in Cd-treated soil accumulated in roots, regardless of the Cd level in the soil. Root Cd concentrations ranged from 2.6 mg kg^-1 (control plants) to 505.7 mg kg^-1 (Totem plants grown in soil at highest Cd and a soil pH 5.1) and were directly related to soil Cd concentrations. Cd translocation from roots to leaves and fruit was very limited, resulting in a maximum Cd concentration in root leaf tissue of 10.2 mg kg^-1. Accumulation of Cd in fruit was found to correlate well with leaf Cd, although even at the highest amount of applied Cd, fruit Cd concentration did not exceed 700 g kg^-1 of fresh weight.Contribution no. 951     

Long-distance signals positively regulate the expression of iron uptake genes in tobacco roots

Long-distance signals generated in shoots are thought to be associated with the regulation of iron uptake from roots; however, the signaling mechanism is still unknown. To elucidate whether the signal regulates iron uptake genes in roots positively or negatively, we analyzed the expressions of two representative iron uptake genes: NtIRT1 and NtFRO1 in tobacco (Nicotiana tabacum L.) roots, after shoots were manipulated in vitro. When iron-deficient leaves were treated with Fe(II)-EDTA, the expressions of both genes were significantly reduced; nevertheless iron concentration in the roots maintained a similar level to that in roots grown under iron-deficient conditions. Next, all leaves from tobacco plants grown under the iron-deficient condition were excised. The expression of two genes were quickly reduced below half within 2 h after the leaf excision and gradually disappeared by the end of a 24-h period. The NtIRT1 expression was compared among the plants whose leaves were cut off in various patterns. The expression increased in proportion to the dry weight of iron-deficient leaves, although no relation was observed between the gene expression and the position of excised leaves. Interestingly, the NtIRT1 expression in hairy roots increased under the iron-deficient condition, suggesting that roots also have the signaling mechanism of iron status as well as shoots. Taken together, these results indicate that the long-distance signal generated in iron-deficient tissues including roots is a major factor in positive regulation of the expression of NtIRT1 and NtFRO1 in roots, and that the strength of the signal depends on the size of plants.     

Seed Dormancy in Acer: An assessment of the Rôle of the Structures Covering the Embryo

Cells of a seven year old strain of Papaver somniferum L. when cultured for 2 weeks and incubated with substances known to elicit the formation of phytoalexins, responded by turning reddish brown within 6 h and accumulating sanguinarine. Morphinan alkaloids were not detected. Media (100 ml) containing 1 ml of Botrytis spec. preparations raised the level of sanguinarine in the cells 26 times over the maximum level found in controls. Over a culture period of 79 h the cells achieved a sanguinarine concentration of 2.9% of dry weight. Media (100 ml) with 1 ml of Rhodotorula rubra preparation, 15 mg arachidonic acid, 1 mg actinomycin, 0.5 ml of Helminthosporium gramineum, Sclerotinia sclerotiorum, or 5 ml Colletotrichum gloeosporoides preparation elicited a considerable, but relatively weaker response. Sanguinarine accumulation was also found to occur in the medium and reached a concentration of 43% of total sanguinarine per culture when cells were cultured in 100 ml medium with 5 ml Colletotrichum preparation for 24 h. Young poppy cell cultures initiated 9 months ago responded to the presence of Botrytis material as did 7-year-old cultures.