Evaluating the role of seed priming in improving drought tolerance of pigmented and non‐pigmented rice

This study was conducted to evaluate the influence of seed priming on drought tolerance of pigmented and non‐pigmented rice. Seeds of pigmented (cv. Heug Jinju Byeo) and non‐pigmented (cv. Anjoong) rice were soaked in water (hydropriming) or solution of CaCl₂ (osmopriming). Seeds were sown in soil‐filled pots retained at 70 (well‐watered) and 35% (drought) water‐holding capacity. Drought stress caused erratic and poor stand establishment and decreased the growth of both rice types. More decrease in plant height and leaf area under drought stress was noted in pigmented rice, whereas decrease in root length and seedling dry weight, under drought, was more obvious in non‐pigmented rice. Pigmented rice maintained more tissue water and photosynthesis and had more polyphenols, flavonoids and antioxidant activity than non‐pigmented rice. Seed priming was effective in improving stand establishment, growth, polyphenols, flavonoids and antioxidant activity; however, extent of improvement was more in pigmented rice under drought. In conclusion, drought caused erratic germination and suppressed plant growth in both rice types. However, pigmented rice had better drought tolerance owing to uniform emergence, and better physiological and morphological plasticity. Seed priming was quite helpful in improving the performance of both rice types under drought and well‐watered conditions.     

Response of Wheat and Barley during Germination to Seed Osmopriming at Different Water Potential

Pre-sowing osmotic seed treatments were evaluated as a means of improving water uptake and germination performance of wheat ( Triticum durum L. cv. Hourani-27) and barley ( Hordeum vulgare L. cv. ACSAD 176) under four levels of water potential (0, –0.4, –0.8 and –1.2 MPa) created by using polyethylene glycol 8000. Seeds were osmoprimed in aerated solutions of 0.0, 0.2, 0.4 or 0.6 M KCl at 24 ± 2°C overnight and then rinsed and dried. Rate of water uptake by seeds was higher in osmoprimed than untreated seeds of both crops regardless of the water potential level. Decreasing water potential (more stress) adversely affected rate of water uptake in seeds of both crops. Seeds osmopriming increased germination percentage and decreased time to 50% germination at high water potentials (low stress), whereas the germination at low water potentials (more stress) was not affected by osmopriming treatments. The effect of osmopriming on rate of water uptake, germination percentage, and time to 50% germination was more pronounced in wheat than in barley. Reduction in the lag time of imbibition may be accounted for in part by some germination rate enhancement in the osmopriming treatments. Fresh weight and length of shoots (plumules) and roots (radicles) were enhanced in osmoprimed seeds in comparison to untreated seeds, in both crops at high water potentials (0 and – 0.4 MPa). As water potential in the medium decreased, these traits were inversely affected regardless of osmopriming treatment. Longer roots in wheat compared to barley were noted in the positive osmopriming treatments at high water potentials (0 and – 0.4). These results might indicate that wheat is more responsive than barley at relatively high water potentials to osmopriming through rapid penetrating root system.     

Potential of zinc seed treatment in improving stand establishment,phenology, yield and grain biofortification of wheat

Abstract

One of the problems in obtaining high wheat yield is the unavailability of micronutrients in balanced quantities. Zinc is an essential micronutrient due to its involvement in many metabolic processes in plant. In this experiment, seeds of two wheat cultivars (Faisalabad-2008 and Lasani-2008) were subjected to soak in aerated Zn solution of 0.1 and 0.01?M for 12?hr. For the seed coating, Zn was adhered to the wheat seeds by using Arabic gum by using zinc sulfate (ZnSO₄·7H₂O) as a source. Untreated dry seeds were considered as a control. Results indicated that field emergence was improved by Zn seed treatments, maximum numbers of seedlings were observed in seed priming with 0.01?M Zn solution. Seed osmoprimed with 0.01?M Zn solution improved the grain yield, biological yield, and other yield related traits. Grain and straw Zn enrichment were also enhanced in seed osmoprimed with 0.01?M Zn solution.     

Improving the Productivity of Bread Wheat by Good Management Practices under Terminal Drought

Drought‐induced damages in crop plants are ranked at top amid all losses instigated by diverse abiotic stresses. Terminal drought (drought at reproductive phase) has emerged as a severe threat to the productivity of wheat crop. Different seed enhancement techniques, genotypes and distribution of crop plants in different spacings have been explored individually to mitigate these losses; however, their interaction has rarely been tested in improving drought resistance in wheat. This study was conducted to evaluate the potential role of different seed enhancement techniques and row spacings in mitigating the adversities of terminal drought in two wheat cultivars during two consecutive growing seasons of 2010–2011 and 2011–2012. Seeds of wheat cultivars Lasani‐2008 (medium statured) and Triple Dwarf‐1 (dwarf height) soaked in water (hydropriming) or CaCl₂ (osmopriming) were sown in 20‐, 25‐ and 30‐cm spaced rows; just before heading, the soil moisture was maintained at 100 % field capacity (well watered) or 50 % field capacity (terminal drought) till maturity. Terminal drought significantly reduced the yield and related traits compared with well‐watered crop; however, osmopriming improved the crop performance under terminal drought. Among different row spacings, wheat sown in 20‐cm spaced rows performed better during both years of study. Wheat cultivar Lasani‐2008 performed better than cultivar Triple Dwarf‐1 under both well‐watered and stress conditions. Maximum net returns and benefit–cost ratio were recorded from osmoprimed seeds of cultivar Lasani‐2008 sown in 20‐cm spaced rows under well‐watered condition. Nonetheless, osmoprimed seeds of cultivar Lasani‐2008 sown in 20‐cm spaced rows were better able to produce good yield under terminal drought.     

种子引发技术研究进展

种子引发是一项能有效提高种子质量的种子处理技术,具有广阔的应用前景。对现有种子引发的基本技术,如水引发、滚筒引发、渗调引发、固体基质引发,以及生物引发、膜引发、脱落酸引发、起泡柱引发等种子引发新技术进行了概述,对未来种子引发技术进行了研究讨论。     

PEG渗调引发处理对菜薹老化种子DNA损伤的修复作用

利用ＲＡＰＤ技术对菜薹人工老化种子ＤＮＡ的损伤及ＰＥＧ渗调引发处理的修复作用进行了研究。在６１种引物中,有６种在菜薹人工老化的种子上获得了基因组ＤＮＡ指纹图谱,平均每种引物扩增的总ＤＮＡ带数为２．１６,多态性ＤＮＡ带数为１．１７,有１１种引物在ＰＥＧ渗调引发的菜薹老化种子上获得了基因组ＤＮＡ指纹图谱,平均每种引物扩增的总ＤＮＡ带数为３．９１,多态性ＤＮＡ带数也是３．９１。人工老化对菜薹种子基因组Ｄ     

人工老化和PEG渗调修复对黄瓜种子浸泡液电导率及种子萌发的影响

采用人工老化不同时间（1-13 d）后25%PEG渗调修复24 h的黄瓜种子,测定2种条件下种子浸泡液电导率的变化和种子萌发情况。测定结果显示,老化时间越长,老化种子浸泡液的电导率越大,种子的发芽率、简化活力指数和活力比减小;PEG渗调后,其电导率均下降,简化活力指数和活力比都有所提高,但是发芽率变化不大。因此,PEG处理老化种子可以一定程度上修复细胞膜,降低膜的通透性,促进种子的萌发。     

Plant Emergence of PEG-osmoprimed Seeds under Suboptimal Temperatures in Two Cultivars of Sweet Sorghum Differing in Seed Tannin Content

The effect of polyethylene glycol (PEG) osmopriming on plant emergence in laboratory at optimal (25 °C) and suboptimal (18 and 14 °C) temperatures was assessed in two cultivars of sweet sorghum differing in kernel colour: Brandes, light-coloured, and Roce, dark-coloured. Sterilized sand or non-sterilized soil were used as substrates. PEG osmopriming enhanced seedling emergence in sand. In soil, the light-seeded cultivar produced seedlings only at optimum temperature, whereas the unprimed dark-seeded cultivar performed well as in sand at all temperatures and reduced dramatically its germination capacity at suboptimal temperatures following priming treatment. These results might be related to the presence of tannins in the seed coat. Seed tannin contents of 80 and 590 mg 100 g⁻¹ seed fresh weight (FW) were determined in Brandes and Roce respectively. These amounts consistently reduced after PEG osmopriming, especially in Roce (217.5 mg 100 g⁻¹ seed FW). The decline in tannin content in Roce, because of osmopriming, might explain the poor emergence of this cultivar in soil. These results suggest the opportunity of using high-tannin cultivars of sweet sorghum in the field, which may better growth in this environment when early sowings are required.     

Effects of osmopriming and hydropriming on vigour and germination of China aster (Callistephus chinensis (L.) Nees.) seeds

The aim of this research was to evaluate the effects of osmopriming and different hydropriming treatments on the vigour and germination of China aster (Callistephus chinensis) seeds. Seed vigour and germination tests were conducted at 10, 20 and 30°C in darkness for untreated, osmoprimed and hydroprimed seeds. The following parameters and categories of seeds and seedlings were evaluated: the mean germination time (MGT), T10, T50, U75–25, U90–10, the percentage of germinating seeds (Gmax), germination capacity, percentage of abnormal seedlings and dead seeds. The results showed that osmopriming accelerated seed germination to the largest extent and improved the uniformity of germination at 10 and 30°C. Among the hydropriming treatments the highest speed of germination was observed for seeds hydrated in 500 μL of water per 1 g of seeds for 48 h at 15°C. This treatment accelerated seed germination at 10°C compared with the control. Osmopriming increased seed germination capacity at 30°C. None of the applied hydropriming treatments improved this parameter.     

黄瓜老化种子基因组DNA的损伤与修复的RAPD研究

应用RAPD技术对人工老化和PEG处理的黄瓜种子进行扩增多态性DNA分析.建立了黄瓜种子基因组DNA的损伤及其修复的RAPD指纹图谱.在92条引物中有22条可应用于老化种子的研究.16条可应用于PEG处理种子的研究,并从中找出了6条引物S190、S300、S359、S475、S1140、S2144用来比较黄瓜老化种子及其修复的RAPD扩增带型的变化.结果发现,人工老化处理的黄瓜种子的DNA带减少甚至消失.而PEG渗调修复后的黄瓜老化种子DNA带重新出现或者与对照基本相同,从而建立了黄瓜老化种子基因组DNA的损伤与修复的RAPD指纹图谱.