Plant Shoot Length Research Articles

Effect of Seed Tuber Weights on the Development of Tubers and Flowering Spikes in Japanese Yams (Dioscorea japonica) Grown under Different Photoperiods and with Plant Growth Regulators

The effect of seed tuber (ST) weight on the development of main shoots, aerial tubers (bulbils, AT), new tubers (below ground, NT), and flowering spikes (inflorescences) was examined in Japanese yam plants (Dioscorea japonica) grown under different photoperiods and with plant growth regulators (PGRs). Within the same PGR and ST-weight group, the main shoot lengths of plants grown under a 24-h photoperiod (constant light, LD) were found to be longer than those grown under an 8-h photoperiod (SD) in all seasons. Furthermore, within the same photoperiod and ST-weight group, except for the plants grown from 25 g of ST (25gST plants) under SD conditions, the main shoot lengths of control and gibberellic acid (GA3)-treated plants were found to be longer than those of uniconazole-P (Uni)-treated plants. These tendencies were stronger in the 50gST plants than in the 25gST plants. In the 25gST plants, the final fresh weight (FW) of NT and the combined FW of AT and NT were greater in plants grown under LD conditions (LD plants) than those of SD plants; however, this was not observed in the case of the 50gST plants. This is because AT and NT development commenced earlier in the 25gST plants than in the 50gST plants. Furthermore, in the case of the 25gST-LD plants, the control plants also produced a few AT. Hence, we could confirm that the yield of NT was slightly increased by the inhibition of AT in the GA3-treated plants. The 25gST or 50gST-SD plants had only one peak of spike development from June through July, whereas the 25gST or 50gST-LD plants had two peaks of spike development, that is, in June and July and then again from September through October. In the season (June to July) of early spike development, the number of spikes per LD plant was greater than that in the SD plants, and the total number of spikes per plant was inhibited by GA3 treatment. These tendencies were stronger in the 50gST plants than in the 25gST plants.

Plant microcosm studies demonstrating bioremediation of cyanide toxicity by Trichoderma and Fusarium spp.

The biodegradation of cyanide by Trichoderma and Fusarium spp. growing in association with plant roots in microcosms was investigated with CN− at 50 or 100 mg/kg. Pea and wheat seeds germinated and plants grew only when seeds were inoculated with the fungi, probably because the plant/fungal association was capable of promoting cyanide catabolism. Inoculation by fungi also increased plant shoot lengths and the biomass of shoots and root compared with control plants without CN− and fungi. Such plant/fungal association shows potential as a land remediation system.

Effect of textile effluents on growth performance of wheat cultivars

Laboratory experiments were conducted to study the effect of different concentrations in the range of 0–100% textile effluents (untreated and treated) on seed germination (%), delay index (DI), plant shoot length and root length, plant biomass, chlorophyll content and carotenoid of three different cultivars of wheat. The textile effluent did not show any inhibitory effect on seed germination at low concentration (6.25%). The other reported plant parameters also followed the similar trend. Seeds germinated in undiluted effluents did not survive for longer period. Based on the tolerance to textile effluent, the wheat cultivars have been arranged in the following order: PBW-343 < PBW-373 < WH-147. It has also been concluded that effect of the textile effluent is cultivar specific and due care should be taken before using the textile effluent for irrigation purpose.

Impact of Aspergillus niger AN27 on growth promotion and sheath blight disease reduction in rice

Sheath blight caused by Rhizoctonia solani Kuhn is a threat to rice cultivation in different agroclimatic conditions. Many bacteria and fungi from rice field soils are antagonistic to R. solani (Gogoi and Roy 1993, Roy 1984, 1993, Sen et al 1993). We tested the ability of Aspergillus niger AN27 and its bioformulation to suppress sheath blight. Seeds of Pusa Basmati 1 were planted in four nursery trays (650 seeds tray -1 ). Seeds of one tray were treated with the bioformulation Kalisena SD at 4 g kg -1 before planting. Untreated seeds were sown in the other three trays. At transplanting, root and shoot length of plants and biomass were measured for each treatment. Twenty-five-day-old seedlings were transplanted at 15x 15-cm spacing in a randomized block design with four treatments. Three replications of two 3-m rows were maintained. Standard agronomic practices were followed. The experiment was conducted for two continuous crop years (1997 and 1998). Plants were inoculated with a virulent isolate of R. solani by placing two colonized typha bits (Bhaktavatsalam et al 1978) in the center tillers of each hill at 40 d after transplanting (maximum tillering). At 45 d after inoculation, number of total tillers, infected tillers, effective tillers, lesion height, and disease reduction were measured.

Induction ofent-kaurene biosynthesis by low temperature in dwarf peas

Germinating pea (Pisum sativum L.) seeds of two dwarf cultivars, “Progress No. 9” and “Green Arrow”, and two tall cultivars, “Alaska” and “Alderman”, were treated with low temperature (3–5°C) for 14 days and then transferred to normal growing conditions (19–21°C for 16 h/14.5–16.5°C for 8 h) for an additional 10 days. Biosynthesis of [14C]ent-kaurene from [14C]2-mevalonic acid (2-MVA) was assayed in cell-free enzyme extracts prepared from shoot tips 10 days after cold treatment and was compared with activity in enzyme extracts prepared from noncold-treated, 10-day-old control plants. Shoot lengths of cold-treated plants were measured throughout a 35-day period and compared with shoot lengths of plants grown without cold treatment for 25–35 days. Low temperature induced a five-to 10-fold enhancement ofent-kaurene, hence potentially gibberellin (GA), biosynthesis in seedlings of the two dwarf cultivars but not in the tall cultivars. However, the lack of an increase in growth rate in the cold-treated dwarfs indicated that endogenous GA biosynthesis remained blocked at some point beyondent-kaurene in the biosynthetic pathway. Since the late-flowering “Alderman” cultivar did not exhibit enhanced biosynthesis ofent-kaurene, it appears that if vernalization in late-flowering cultivars of peas is correlated with enhanced GA biosynthesis, it is not the early part of the biosynthetic pathway which is affected.

Perspectives of recycling gamma irradiated sewage-sludge in agricultural applications: A study on methi ( Trigonella foenum-graecum L.: leguminosae)

The effects of gamma-irradiated sludge on the growth and yield of methi ( Trigonella foenum-graecum L.) in pot cultures have been studied. Gamma-irradiated sludge was found to inhibit the shoot length after 45 and 90 days of plant growth compared to plants grown in soil containing unirradiated sludge. The untreated sludge did not exhibit any detrimental effect on the shoot length of plants compared to the control. The root length of plants grown in soil supplemented with either gamma-irradiated or unirradiated sludge was found to be inhibited after 45 days of growth. However, irradiation of sludge resulted in the higher inhibition of root length of plants compared to when unirradiated sludge was used. The gamma-irradiated sludge appeared to negatively affect the physical growth parameters of the plant. The significant positive effect of gamma-irradiated sludge was observed on the biochemical growth parameters and yield of methi plants. There was a 3·5-, 1·7- and 2-fold increase in the total protein content, total soluble sugars and starch content, respectively, of plants grown in soil supplemented with gamma-irradiated sludge after 45 days of growth. The gamma-irradiated sludge did not show any detrimental effect on any of the three biochemical parameters studied, even after 90 days of plant growth. The sludge obtained from the conventional treatment process was found to be inhibitory to the protein and starch content of plants in the latter stages of plant growth. A significant increase in the yield of methi plants, after 45 as well as 90 days, grown in the presence of gamma-irradiated sludge indicates a beneficial effect of recycling of irradiated sludge for agricultural applications.

Effects of Static versus Flowing Water on Aquatic Plant Preferences of Triploid Grass Carp

Triploid grass carp Ctenopharyngodon idella were presented with three aquatic plant species (sago pondweed Potamogeton pectinatus, Eurasian watermilfoil Myriophyllum spicatum, and American pondweed P. nodosus) in outdoor canals with static and flowing water in winter, spring, and summer. Plant consumption by triploid grass carp in winter was low but increased dramatically in spring and summer. Based on plant shoot lengths, triploid grass carp preferences in spring for static water were sago pondweed = American pondweed, American pondweed = Eurasian watermilfoil, sago pondweed > Eurasian watermilfoil; for flowing water, sago pondweed = Eurasian watermilfoil > American pondweed. Summer preferences for static water were sago pondweed = Eurasian watermilfoil = American pondweed; for flowing water, sago pondweed = Eurasian watermilfoil = American pondweed. Plants of all three species produced longer shoots in canals with flowing water than with static water. The differences in shoot length may have altered the triploid grass carpˈs consumption rate and preference. Flowing conditions also had varying effects on nutritional content of plants, as shown in proximate analyses of dry matter and percent of fat, ash, protein, crude fiber, nitrogen free extract, and acid detergent fiber. Ash content was consistently higher in plants of all three species from canals with flowing water. This may reflect a morphological response to flow by the plants. None of the variables of the proximate analysis of plants correlated statistically with preference. This suggests that accessibility and ease of mastication were more important in determining preference than nutritional quality of the plants. Algae consumption by triploid grass carp, however, made it difficult to discern correlations between nutritional factors and vascular plant consumption.

Root-zone Temperature Affects Water Status and Growth of Red Maple

Abstract Red maple (Acer rubrum L.) plants were evaluated for their responses to 5 weeks of constant root-zone temperatures from 18 to 36C. Shoot lengths of plants grown with 18 to 30C root zones did not differ significantly from one another at any time during the study, and shoot dry weights of these plants were similar. However, after 21 days of exposure, shoot length of plants grown with roots at 36C was significantly less than that of plants with roots grown at 30C and below. Leaf area was greatest among plants with roots at 24C, and mean shoot and root dry weights of plants in the 36C treatment were 57% and 68% less, respectively, than those for plants with roots at 30C. Leaf diffusive resistance of plants grown at 36C was five times greater than for plants with root zones at 30C or below. Shoot water potential decreased with increasing temperature, but increased solute concentration in leaves of 36C-grown plants probably contributed to turgor maintenance.