Total Dry Weight Of Seedlings Research Articles

Effects of sand burial on seedling growth of the coastal dune plant Viola grayi: Tolerance and adaptive responses to sand accretion

AbstractThe responses of Viola grayi seedlings to complete sand burial were experimentally assessed in this study. Approximately 10‐month‐old seedlings were buried in sand to a depth of 0, 1, 5, or 15 cm. The re‐emerged seedlings were counted for 5 months, and the dry weights were compared. The results showed that shallow burial promoted the shoot development and total growth of seedlings. The dry weights of stems and leaves and the total dry weight of seedlings were higher in plants buried at depths of 1 and 5 cm than in unburied plants. The dry weight of roots did not differ among them. No seedlings buried at a 15‐cm depth re‐emerged. Most seedlings buried at 1‐ and 5‐cm depths produced adventitious roots from below‐ground stems. The tolerance and adaptive responses of V. grayi seedlings to sand accretion may contribute to their establishment in sand‐accumulating habitats.

Respon Pertumbuhan Bibit Salak (Salacca Zallaca) terhadap Dosis Spora Endomikoriza pada Media Pembawa Pasir Kuarsa dan Zeolit

Response of Salak Seedlings (Salacca Zallaca) Growth to Dosage of Endomycorrhizal Spore in Quartz Sand and Zeolite Carrier Media. This study aimed to study the effect of endomycorrhizal spore dosage and carrier media that were applied directly to the roots of salak plants. The research designed as factorisl by using Randomized Block Design with 2 treatment factors. The first factor was number of endomycorrhiza spores consists of 4 levels i.e 0, 75, 150, and 225 spores per 500 g carrier media per polybag, while the second factor was the type of carrier media consist of 2 levels i.e zeolite and quartz sand. The results showed that interaction between endomycorrhizal spore dosage with carrier media did not significantly influence the growth of salak seedlings. Endomycorrhizal spores in doses of 75, 150 and 225 spores per polybag increased root infection and leaf P nutrient content compared to control, but seed height, leaf area, shoot dry weight, root dry weight and total dry weight of seedlings not significantly difference. The zeolite carrier media caused root infection by mycorrhizal was higher than quartz sand media, but the P nutrient uptake and seedling growth were not significantly different. Based on the results of this study it is necessary to make a longer observation of the effect of endomycorrhizal spore doses and carrier media on the growth of salak seedlings.

Varietal and germinative characterization of Agave potatorum (Asparagaceae) seeds with different origins

Background: Agave potatorum reproduces mainly through seeds is widely collected for the mezcal production, and there is currently a marked decrease in their wild populations. Therefore, to contribute to its sustainable use, it is important to characterize the morphology of its seeds and to know their germinative characteristics.Research question: Do the year and the collection site have an effect on the size, color, viability and germination capacity of Agave potatorum seeds?Species studied: Agave potatorum Zucc.Study site and period of research: Seeds of Agave potatorum were collected in Oaxaca, Mexico: Miahuatlán (MIAH), in 2014; Coixtlahuaca (COIX), in 2015; and Zaachila (ZAA), in 2015 and 2016.Methods: For the seeds, we analyzed four physical descriptors, five color coordinates, and nine germination variables. We used a completely randomized design with four replications (100 seeds). An analysis of variance, a comparison of means, and a linear correlation analysis were performed.Results: We found that the ZAA16 seeds showed the highest values ( P < 0.05) for weight and size, and for the luminosity coordinate (L*, 15.2). Color coordinate values revealed a black color of the seeds, which significantly diminished in luminosity with seeds age and varied with their origin. The coordinate L* was correlated significantly with the total dry weight of seedlings and seed volume.Conclusions: Agave potatorum seeds significantly changed their physical dimensions and germination capacity according to their origin. The luminosity of the black color of seeds decreased with seed age and was correlated with seed volume and seedling total dry weight.

Seed priming with salicylic acid and hydrogen peroxide alleviates water deficit in wheat (Triticum aestivum L.) at seedling stage

Present experiment was undertaken during 2013–14 and 2014–15 to evaluate the effectiveness of exogenous application of hydrogen peroxide (H2O2) and salicylic acid (SA) through seed priming during water deficit on wheat seeds of two contrasting genotypes C-306 (relatively drought resistant) and HD-2329 (relatively drought susceptible). Under PEG- 6000 induced water deficit, significant differences were observed between different treatments in both the genotypes. Priming with water, SA and H2O2 improves germination rate and seedling vigour during water deficit with respect to T2(non-primed) in both the genotypes. Root length, shoot length, root dry weight, shoot dry weight and total dry weight of seedlings were also recorded to be increased significantly with respect to T2. The treatment T5 in which SA and H2O2were applied in combination, showed maximum value for the observed parameters. HD-2329 was observed to be more responsive to the priming treatments during water deficit, with respect to C-306. It may be concluded that seed priming with SA and H2O2 improves tolerance to PEG-6000 induced water deficit and they act synergistically in improving performance of seedlings of wheat.

The Shape of the Female Fitness Curve for Cynoglossum officinale: Quantifying Seed Dispersal and Seedling Survival in the Field

Abstract: When hermaphroditic plants shift their sex allocation to produce more seeds and less pollen, it is frequently assumed that the female component of fitness is strictly proportional to the number of seeds produced. However, if producing more seeds results in more competition between seedlings, the female fitness gain curve levels off with high investments in seeds. The shape of this curve is relevant for sex allocation theory, but rarely have data been collected. For Cynoglossum officinale we described the relationship between the number of seeds produced on the mother plant and the number and weight of seedlings in September of the following year. As expected, around large plants of C. officinale more seedlings were retrieved after the germination period in March. The seedlings of large plants were dispersed over an area similar to that of small plants. As a result, seedlings around large plants had a significantly higher chance to have a neighbouring sibling within one dm2. Survival and growth of single or grouped (density > 2) seedlings did not differ significantly. As a result, total dry weight of seedlings in September was a linear function of the number of seeds on the parent plant. Our data indicate a linear female fitness gain curve.

Effects of far-red light on the growth, mycorrhizas and mineral nutrition of Scots pine seedlings

The effects of supplementary far-red sidelight on the formation of mycorrhizas and on the accumulation and allocation of dry weight and mineral nutrients were studied in Scots pine (Pinus sylvestris L.) seedlings. Starting one week after germination the seedlings were subjected to two different light quality regimes: control and simulated sparse-canopy conditions (FR+). In the FR+ regime, light reflected by neighbouring plants was simulated by means of supplementary far-red light sources, which reduced the horizontal red/far-red photon ratio (R:FR) without affecting PAR. Seedlings were harvested after three months of treatment. FR+ increased stem height and decreased the total dry weight of seedlings. Dry weight allocation to needles was not affected, whereas dry weight allocation to roots was reduced and that to stems was increased in FR+ treated seedlings. The total number of short root tips and developing mycorrhizas per seedling were lower in FR+ than in control plants. Most short roots were developing mycorrhizas, while non-mycorrhizal short roots and mycorrhizas with mantle or external mycelium were very scarce. Changes in the allocation of nutrients in general followed the changes in dry weight allocation, and changes in nutrient content followed those in total dry weight. However, mismatches among these changes resulted in significant changes in nutrient concentrations in some organs: the concentrations of nitrogen and potassium in needles and the concentration of nitrogen in stems were higher in FR+ than in control seedlings. Changes in biomass and nutrient allocation under low R:FR may promote rapid height growth during early development in stands of Scots pine seedlings, but concomitant reductions in growth of the root system and mycorrhizas may negatively affect tree performance over the long term.

Carbon and phosphorus partitioning in Pinus serotina seedlings growing under hypoxic and low-phosphorus conditions.

Ten-week-old pond pine (Pinus serotina Michx.) seedlings were grown in solution culture at 5 or 100 microM P and under aerobic or hypoxic solution conditions. After 6 and 10 weeks in the treatments, changes in relative growth rate (RGR), P acquisition and allocation, and carbohydrate partitioning were determined by analyzing tissue for total P, soluble sugars and starch. Six weeks of low-P growth conditions decreased seedling dry weight and the ratio of shoot dry weight to root dry weight (S/R) by 39 and 51%, respectively, in comparison to seedlings from the aerobic, high-P (control) treatment. Mean RGRs of shoots in the low-P treatment were reduced by 33%, whereas root growth was unaffected. After 10 weeks of low-P growth conditions, however, both shoot and root RGRs were significantly reduced, and plants had lower S/R ratios than in any other treatment. Slowed shoot growth was accompanied by starch and nonstructural carbohydrate accumulation in needles, indicating that needle growth was not limited by carbohydrate supply. Six weeks of low-P growth conditions decreased total seedling P by 75%, reflecting a 97% reduction in the net uptake rate (NUR). Shoot NUR as a fraction of seedling NUR was also greatly reduced in the low-P treatment, indicating that low-P growth conditions affected P translocation to the shoot more than P accumulation by roots. In contrast, 6 weeks of hypoxic growth conditions decreased total dry weight of seedlings in the high-P treatment by 41% relative to their aerobic counterparts. Root growth was affected more than shoot growth, however, and S/R ratios increased. After 10 weeks, S/R ratios doubled, primarily because of the reduction in root RGR. Nevertheless, roots of hypoxic seedlings contained a higher percentage of total seedling P than their aerobic counterparts. Net P acquisition per seedling decreased by more than 50% under hypoxic growth conditions, as a result of reductions in both root RGR and seedling NUR. Starch accumulation in shoots of hypoxic seedlings reflected reductions both in root growth and in transport of carbohydrates to nonwoody roots. Carbohydrate availability did not appear to be limiting growth of hypoxic woody roots, which are well-aerated internally, but it may have limited metabolic processes in nonwoody roots of seedlings from the high-P treatment.

Effect of three weeds on the growth and mycorrhizal infection of black walnut seedlings

The effect of unincorporated and incorporated litter and extracts of broom-sedge, fescue, and blackberry on the mycorrhizal development and growth of black walnut seedlings was investigated in two greenhouse experiments. Seedling growth varied with method of litter application. Only fescue extract decreased growth in the extract experiment, but unincorporated and incorporated broom-sedge litter significantly (P ≤ 0.05) reduced seedling total dry weight below that of mycorrhizal control seedlings. The total dry weight of seedlings in incorporated fescue litter was reduced by 47%. The number of mycorrhizal infected root segments on seedlings grown in unincorporated litter was more than twice the number of infected roots on seedlings grown in incorporated litters. Significantly fewer mycorrhizal roots were found on seedlings grown with fescue and broom-sedge litters than on mycorrhizal control seedlings. On the average, incorporation of litter increased the percentage of leaf phosphorus, but the shoot absorption of phosphorus was considerably less for seedlings grown in incorporated fescue litter compared with unincorporated fescue litter. Seedlings grown in fescue extract had 33% less phosphorus than control seedlings. Except for possible interference with mycorrhizal development when litter was incorporated, there was no evidence to suggest that blackberry litter contains substances that are allelopathic to black walnut.

Seedling Growth of Cicer Milkvetch as Affected by Seed Weight and Temperature Regime1

Seedling vigor of cicer milkvetch (Astragalus cicer L.) has been improved by breeding for high seed weight, but it is not known how growth characteristics differ among seedlings derived from seed of different weight classes. Therefore, the objective of this study was to determine the effect of seed weight (3.2, 3.6, 4.0, 4.4, 4.8, 5.2, and 5.6 g/1,000 seeds) and temperature regime (20 C day/15 C night and 25 C day/20 C night) various seedling growth traits. When averaged over all sampling dates, temperature regime significantly affected area of upper leaves; dry weight of cotyledons, primary leaf, upper leaves, stems, and roots; height of seedlings; total dry weight of shoots; and total dry weight of seedlings. Values for all traits except weight of cotyledons and primary leaf were higher at 25/20 C than at 20/15 C. Cotyledon area and primary leaf area were not influenced by temperature. Within a temperature regime, seed weight also significantly affected all characters. For most seedling traits an increase in dry weight or area was associated with increased seed weight.In a growth analysis study, temperature treatments significantly affected initial seedling weight, initial leaf area, relative growth rate, relative leaf area expansion rate, relative leaf weight expansion rate, leaf area partitioning coefficient, leaf weight partitioning coefficient, and final seedling weight. Temperature regime did not affect initial leaf weight and net assimilation rate. Seed weight was positively and linearly associated with initial seedling weight, initial leaf area, and initial leaf weight at both temperatures and with final seedling weight at 20/15 C. The lack of association of seed weight with some important growth analysis traits suggests that certain seedling vigor characters are entirely independent of seed weight. The initial advantage of high seed weight progenies, however, tended to be maintained in the early phases of seedling development, as indicated by final seedling weight. Thus, with populations selected for high seed weight, additional progress in improving seedling vigor might be achieved through selection for relative leaf area expansion rate, net assimilation rate, or other traits.

Allelopathic potential of ground cover species onPinus resinosa seedlings

Water extracts of foliage ofAster macrophyllus, Lonicera tatarica, Solanum dulcamara, Solidago gigantea, Prunus serotina, andRubus idaeus var.strigosus, collected from the ground vegetation of a red pine (Pinus resinosa Ait.) plantation, were tested for potential allelopathic effects on seed germination, radicle elongation, and growth of red pine seedlings. Seed germination was not significantly affected by extracts, but radicle elongation of newly germinated seeds was reduced by up to 48% compared to controls. All extracts variously inhibited height growth, formation of secondary needles, and dry weight increment of young red pine seedlings during a seven-week experiment. Total dry weight of seedlings treated with Lonicera extract was only 46% that of control plants. Phosphorus concentration in needles treated with Lonicera or Solidago extracts was significantly lower than that of controls. Growth inhibition was not mediated by pH effects or osmotic potentials of the extracts. The data suggest that allelopathic inhibition of red pine is possible, but additional field experiments are needed to evaluate the significance of allelopathy in red pine plantations.

Evaluation of Chickpea (<i>Cicer arietinum</i> L.) Genotypes for Quality Seedlings

A study was conducted to evaluate 100 chickpea genotypes to explore their genetic diversity in respect of emergence and growth attributes. A high genotypic variation was observed in the characters studied. The highest positive correlation corresponded to the root mass and total plant biomass of the seedlings. Seedling biomass production was highly subjective to seedling vigor. Using discriminant function analysis, the first two functions contributed 46.2 and 39.0%, and altogether 85.2% of the variability among the genotypes. Function 1 was positively related to dry weight of root and total plants. The character with the greatest weight on function 2 was seedling emergence rate. The total dry weight of seedlings played the most dominant role in explaining the maximum variance in the genotypes. The genotypes were grouped into six clusters. Each cluster had specific seedling characteristics and the clusters 5 and 6 were closely related and clearly separated from clusters 1 and 4 for their higher amount of root and total biomass production, and vigorous seedlings, where as, the genotypes in cluster 2 and 3 were intermediate. The genotypes in cluster 5 followed by cluster 6 appeared to be important resources for selecting and developing chickpea variety. Keywords: Chickpea; genotypes; seedling; quality DOI: 10.3329/agric.v8i2.7584 The Agriculturists 8(2): 108-116 (2010)