Posted: May 1st, 2020

3-4 paragraph summary due after 12 hours

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Note:
1- Put 2 citation and the references

2- I have attached 3 pictures that include a sample summary, Instructions set and the rubric. 

Go through each picture and then summarise the text – Just as the teacher asked.

Summarise the following Intro:

KEY WORDS: salinity, corn, priming, germination

INTRODUCTION

Environmental stresses, especially drought and salinity are the major causes led to the decline of agricultural products in the world than other factors (Shiri et al., 2009). Salinity damage in plants occurs usually through disorders in water absorption, the effect of ion toxicity and absorption of nutrients (Anvari et al., 2009).Germination is the most important phase of plant life and tolerance to salinity has great importance for germination, emergence and establishment of plants that grow in saline soils (Haghighi & Milani, 2009). Salinity changes the balance of nutrients, soil water availability and reduces the quality of cultivated lands, alters the structure of ecological communities, induces physiological drought through osmotic stress and thus reduces the rate of photosynthesis and growth (Moons et al., 1995; Ianovici, 2011; Khatami et al., 2016). During salinity stress in addition to reducing water absorption, there is an accumulation of some ions at high concentrations in plant tissue which causes to toxicity or ionic imbalance (Fiehn et al., 2002). Because of the abundance and dominance of Na+ and Clin saline water and soil uptake of many of micro and macronutrients will be reduced. So, the high proportion of ions ClTNa+, Ca2+/Mg2+ and Na+/Ca2+present in plant tissues (Grarttan & Grieve, 1999). Many studies on the germination of crop seeds reflect the fact that with increasing salinity radicle and plumule length and also seedling dry weight significantly reduces compared with non-saline conditions (Alebrahim et al., 2004). Corn resistance to salinity increases during growing season, so that seeds and seedlings are less resistant to salinity, but the established plants have appropriate resistance (Emdad & Fardad, 2000).

Seed priming is controlled hydration method until before of radicle emergence and is effective method to improve the rapid and homogeneity emergence of seedlings. This process has a positive effect in reducing the time needed for germination and seedling emergence, final germination and emergence under unfavourable conditions, especially for seeds with low vigour. Seed priming improves seed performance and quality, so can reverse some of the destructive events that occur during aging (Black & Bewley, 2000). Numerous reports has introduced seed priming as a factor of increasing ribosomal RNA synthesis, produce more mitochondrial DNA (Bradford, 1986), increasing the activity of alpha and beta amylase (Powell, 1998), improving germination under salt stress, drought and cold and also improving seed capability for completing germination process under low temperature conditions. Priming can change the amount of proteins, but their type remains unchanged (McDonald, 1999). Soaking seeds with the best concentrations of plant hormones, increase germination and growth as well as increase the efficiency and performance. Gibberellins are a group of hormones that are most directly involved in control and to facilitate germination. Increasing the synthesis and secretion of gibberellic acid (GA3) in the seed causes to breaking down starch into embryo usable materials and beginning of germination.

Marmarin (seaweed extract) is a bio-stimulant and has been used commonly in horticulture. Marine plant extracts enhance the performance and quality of agricultural products in horticulture and because of containing cytokinin, have major physiological effects on crops (Amanpoor Balaneji et al., 2011).

Studies on cucumber (Esmaielpour et al., 2006) and sunflower (Kaya et al., 2006) showed that seed priming with different osmotic agents such as nitrate salts and polyethylene glycol caused to increase in salt tolerance and reduced the ionic toxicity under salinity. Bhattacharjee & Mukherjee (2002) reported that accumulation of proline and soluble carbohydrates in rice seedlings under salinity reduced the negative effects of salinity on the integrity of cell membranes.

The purpose of this study was to determine the effects of salinity on seed germination and seedling growth of maize and evaluation of priming effect to overcome salty conditions.

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