Effects of desiccation on seed germination, cracking, fungal infection and survival in storage of Sterculia foetida L

Seeds of Sterculia foetida were tested for germination following desiccation and subsequent hermetic storage. Whereas seeds at 10.3% moisture content were intact and provided 98% germination, further desiccation reduced germination substantially. The majority of seed coats had cracked after desiccation to 5.1% moisture content. Ability to germinate was not reduced after 12 months' hermetic storage at 10.3% and 7.3% moisture content at 15 degrees C or -18 degrees C, but was reduced considerably at 5.1%. Fungal infection was detected consistently for cracked seeds in germination tests and they did not germinate. However, almost all embryos extracted from cracked seeds germinated if first disinfected with sodium hypochlorite (1%, 5 minutes). In addition. 80 -100% of disinfected extracted embryos from cracked seeds stored hermetically for 28 d at -18 degrees C or -82 degrees C with 3.3% to 6.0% moisture content, and excised embryos stored in this way, were able to germinate. Hence. failure of the very dry seeds of Sterculia foetida to germinate was not due to embryo death from desiccation but to cracking increasing susceptibility to fungal infection upon rehydration. Cracking was associated negatively and strongly with relative humidity and appears to be a mechanical consequence of substantial differences between the isotherms of whole seeds compared with cotyledons and axes.

Training to address attitudes and behaviour of rural bank managers in Madhya Pradesh, India: A programme to facilitate financial inclusion

Given their physical presence in India, banks are arguably well-placed to improve financial inclusion in rural areas. However, uncertain repayment capacities and high transaction costs mean formal financial institutions are often reluctant to lend to the rural poor. Conversely, high transaction costs in dealing with banks are also incurred by clients, through, for example, lengthy, cumbersome and potentially ignominious procedures. Negative attitudes towards poor clients can be an important component of such transaction costs. An applied research project funded by the Enterprise Development Innovation Fund (EDIF-DFID) developed an innovative training programme designed to encourage more positive attitudes of bank staff towards poor clients, and towards their own role in rural poverty alleviation and development. This paper examines the development of the training programme, its implementation, and the results of its evaluation. It is shown that training can bring about attitudinal change, which in turn is reflected in behaviour and social impact.

A field experiment to recreate species rich hay meadows using regional seed mixtures

Species rich semi-natural grasslands are an important but threatened habitat throughout Europe and much of the former area has been lost since the 1950s. However, in some countries large areas have been preserved and the demand for meadow recreation by sowing seed mixtures is increasing. In the White Carpathians Protected Landscape Area (Czech Republic) the use of commercial seed mixtures is undesirable and the use of regional mixtures has been investigated. The costs for seeding large areas are high and lower cost techniques are needed. In 1999 a field experiment was set up to investigate the establishment of hay meadow vegetation comparing sowing a regional mixture all over a plot with sowing narrow 2.5 In strips of regional seed mixtures into a matrix of a commercial grass mixture or into natural regeneration. The results after five seasons showed good establishment of the sown species in the meadow treatment. Spread of sown species from the sown strips into the surrounding matrix occurred but the cover of species was lower in the commercial grass matrix compared with the natural regeneration matrix. Colonisation of some plots by unsown desirable grassland species from adjacent grassland habitats also occurred, but more species colonised the natural regeneration matrix than the commercial grasses or the sown meadow matrix itself. Overall, the results indicate that, in appropriate situations, sown strips can provide a lower cost but slower and longer-term alternative to field scale sowing of regional seed mixtures for recreation of hay meadow vegetation. (C) 2007 Elsevier Ltd. All rights reserved.

Heterotic and seed rate effects on nitrogen efficiencies in wheat

Four field experiments over 2 years investigated whether wheat hybrids had higher nitrogen-use efficiency (NUE) than their parents over a range of seed rates and different N regimes. There was little heterosis for total N in the above-ground biomass (NYt), but there was high-parent heterosis for grain N yields (NYg) in two of the hybrids, Hyno Esta and Hyno Rista, associated with greater nitrogen harvest index (NHI). Overall, the hybrids did not significantly increase the total dry matter produced per unit N in the above-ground crop (NUtE(t)), but did increase the grain dry matter per unit N in the above ground crop (NUtE(g)). The improvement in NUtE(g) was at the partial detriment of grain N concentration. Heterosis for grain NYg in Hyno Esta was lower at zero-N, suggesting that it did not achieve higher yields through more efficient capture or utilization of N. The greater NHI in Hyno Esta appeared to be facilitated by both greater N uptake, and remobilization of N from vegetative tissues, after anthesis. The response of N efficiency and uptake to seed rate was dependent on N supply and season. Where N fertilizer was applied, N uptake over time was slower at the lower seed rates, but where N was withheld N capture at the lowest seed rate soon approached the N capture of the higher seed rates. During grain filling, the rate of accumulation of N into the grain increased with seed rate and the duration of N accumulation decreased with seed rate. With N applied, N yields increased to all asymptote with seed rate, when N was withheld there was little response of N yields to seed rate. In 2002, N utilization efficiency (NUtE(t) and NUtE(g)) also increased asymptotically with seed rate, but in 2003 seed rate had little effect on N utilization efficiency. When nitrogen fertilizer had not been applied, NHI consistently decreased with increasing seed rate. The timing of N application made little difference to NUE, NY, or NUtE.

Nitrogen fertilizer and seed rate effects on Hagberg failing number of hybrid wheats and their parents are associated with alpha-amylase activity, grain cavity size and dormancy

Field experiments were carried out to assess the effects of nitrogen fertilization and seed rate on the Hagberg falling number (HFN) of commercial wheat hybrids and their parents. Applying nitrogen (200 kg N ha(-1)) increased HFN in two successive years. The HFN of the hybrid Hyno Esta was lower than either of its parents (Estica and Audace), particularly when nitrogen was not applied. Treatment effects on HFN were negatively associated with a-amylase activity. Phadebas grain blotting suggested two populations of grains with different types of a-amylase activity: Estica appeared to have a high proportion of grains with low levels of late maturity endosperm a-amylase activity (LMEA); Audace had a few grains showing high levels of germination amylase; and the hybrid, Hyno Esta, combined the sources from both parents to show heterosis for a-amylase activity. Applying nitrogen reduced both apparent LMEA and germination amylase. The effects on LMEA were associated with the size and disruption of the grain cavity, which was greater in Hyno Esta and Estica and in zero-nitrogen treatments. External grain morphology failed to explain much of the variation in LMEA and cavity size, but there was a close negative correlation between cavity size and protein content. Applying nitrogen increased post-harvest dormancy of the grain. Dormancy was greatest in Estica and least in Audace. It is proposed that effects of seed rate, genotype and nitrogen fertilizer on HFN are mediated through factors affecting the size and disruption of the grain cavity and therefore LMEA, and through factors affecting dormancy and therefore germination amylase. (c) 2004 Society of Chemical Industry.

Seed storage of Avicennia alba B1

Seeds of Avicennia alba BI. matured at high moisture content and were sensitive to desiccation: no seeds survived desiccation below 35% moisture content. The effect on survival of a factorial combination of five moist storage treatments (fresh seeds in a polyethylene bag, open with water sprayed over regularly, mixed with sand at 10% moisture content, mixed with moist paddy hulls, or naked seeds mixed with sand at 10% moisture content) and three temperatures (28-30degreesC, 17degreesC and 8-10degreesC) was investigated. In addition, seeds were mixed with sand at 5% moisture content and stored at 17degreesC in order to determine the effect of sand moisture content on seed moisture content and viability during storage. Avicennia alba showed recalcitrant seed storage behaviour, but 75% of the seeds remained viable after four months' moist (45-47% moisture content) storage in 10% moisture content sand at 17degreesC.

Seed survival in Chilean Nothofagus in response to desiccation and storage

Nothofagus alpina, N. obliqua, N. glauca, N. leonii, N. dombeyi and N. pumilio seeds exhibited consistent, albeit slight, sensitivity to extreme desiccation, but nevertheless maintained viability at low moisture contents and cool temperatures (-10 degrees to -20 degrees C) over 2 years. Nothofagus alpina, N. obliqua, N. glauca, N. leonii and N. dombeyi conformed to the seed viability equation of Ellis and Roberts; sensitivity of longevity to temperature was quantitatively similar to that of crop seeds, sensitivity to moisture was somewhat less, and a low-moisture-content limit to the equation was detected at 4.8% moisture content in hermetic storage at 65 degrees C, and possibly similar moisture contents at 30-40 degrees C. These five species show orthodox seed storage behaviour. Therefore, ex-situ conservation of these Nothofagus species in seed banks is possible, but the quality of seed lots collected requires attention. Seed storage behaviour was not defined in N. pumilio: initial seed quality was poor and loss of viability was detected over 2 years at 0 degrees, -10 degrees and -20 degrees C at 2.7% moisture content, but not at 5.2%. The results confirm that the economy of nature in seed storage physiology extends to forest tree seeds, but the repeated observation of reduced sensitivity of longevity to moisture in forest tree seeds requires further investigation.

Long-term effectiveness of sowing high and low diversity seed mixtures to enhance plant community development on ex-arable fields

Questions: How is succession on ex-arable land affected by sowing high and low diversity mixtures of grassland species as compared to natural succession? How long do effects persist? Location: Experimental plots installed in the Czech Republic, The Netherlands, Spain, Sweden and the United Kingdom. Methods: The experiment was established on ex-arable land, with five blocks, each containing three 10 m x 10 m experiment tal plots: natural colonization, a low- (four species) and high-diversity (15 species) seed mixture. Species composition and biomass was followed for eight years. Results: The sown plants considerably affected the whole successional pathway and the effects persisted during the whole eight year period. Whilst the proportion of sown species (characterized by their cover) increased during the study period, the number of sown species started to decrease from the third season onwards. Sowing caused suppression of natural colonizing species, and the sown plots had more biomass. These effects were on average larger in the high diversity mixtures. However, the low diversity replicate sown with the mixture that produced the largest biomass or largest suppression of natural colonizers fell within the range recorded at the five replicates of the high diversity plots. The natural colonization plots usually had the highest total species richness and lowest productivity at the end of the observation period. Conclusions: The effect of sowing demonstrated dispersal limitation as a factor controlling the rate of early secondary succession. Diversity was important primarily for its 'insurance effect': the high diversity mixtures were always able to compensate for the failure of some species.

Seed survival of four tropical tree species in response to environment

The response of seed survival to storage duration and environment (temperature and moisture content) in the four tropical tree species: Cedrela odorata L., Ceiba pentandra (L.) Gaertn., Dalbergia spruceana Benth. and Tabebuia alba (Cham.) Sandwith. from Amazonia conformed to the seed viability equation of Ellis and Roberts. Estimates of the seed viability constants to calculate seed longevity in these species are provided.

Mutant alleles at the rugosus loci in pea affect seed moisture sorption isotherms and the relations between seed longevity and moisture content

Pea (Pisum sativum L.) mutant near-isogenic lines (RRrbrb, rrRbRb, rrrbrb) with lower starch but higher lipid contents, brought about by lesions in the starch biosynthetic pathway, had seed moisture sorption isotherms displaced below that of the wild type (RRRbRb). The negative logarithmic relationship between seed longevity and seed storage moisture content (%, f.wt basis), determined in hermetic storage at 65 degreesC, also differed: longevity in the mutant near-isogenic lines was poorer and less sensitive to moisture content than in the wild type (i.e. C-w was lower). The low-moisture-content limit (m(c)) to this relation also differed, being lower in the mutant near-isogenic lines (5.4-5.9%) than in the wild type (6.1%). In contrast, all four near-isogenic lines showed no difference (P >0.25) in the negative semilogarithmic relationship between equilibrium relative humidity (ERH) and seed longevity. It is concluded that the effect of these alleles at the r and rb loci on seed longevity. was largely indirect; a consequence of their effect on seed composition and hence on moisture sorption isotherms. However, this explanation could not be invoked at moisture contents below mc where differences in longevity remained substantial (RRRbRb double that of rrrbrb). Hence, these mutant alleles affected seed longevity directly at very low moisture contents.