Soil nitrogen pool drives plant tissue traits in alpine treeline ecotones

2020 ◽  
Vol 477 ◽  
pp. 118490
Author(s):  
Jianguo Liu ◽  
Xiaohua Gou ◽  
Anna Gunina ◽  
Xi-En Long ◽  
Fen Zhang ◽  
...  
Author(s):  
Negar Omidvar ◽  
Zhihong Xu ◽  
Thi Thu Nhan Nguyen ◽  
Babak Salehin ◽  
Steven Ogbourne ◽  
...  

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Aradhna Kumari ◽  
Santosh Kumar Singh

Conventional agriculture can result in loss of organic matter (OM), resulting in degradation of cultivated soil. A study was conducted to assess the impact of different tillage treatments in rice and wheat cropping system on soil organic carbon and nitrogen pool. The experiment was carried out in split plot design with four main plot treatments viz. P (direct dry seeding by zero till drill), P 1 2 (direct seeding of sprouted rice in puddle condition), P (hand transplanting) and P (transplanting 3 4 by self-propelled rice trans planter) while the sub plot treatment (for wheat) included T 1 (conventional sowing), T (bed planting), T (strip till drilling) and T (zero till drilling). Significant 2 3 4 variations in SOC and soil nitrogen pool were observed in wheat tillage treatments for D (0-10cm) 1 soil depth. The T and T treatments had significantly higher values of SOC pool as compared to T . 4 3 1 Similar trend was also observed for soil nitrogen. Rice tillage treatments did not have any significant impact on SOC and soil nitrogen at D or subsequent depths. The summarized depths 0- 1 30 and 0-60 cm did not show any impact of the tillage treatments on SOC or soil nitrogen pools.In rice tillage treatments, SOC pool ranged from 26.06 Mg/m3 (P ) to 27.61 Mg/m3 (P ) while the range 4 1 for wheat tillage treatment was 26.30 Mg/m3 (T ) to 26.75 Mg/m3 (T ). At D depth soil N pool was 4 1 1 found to be statistically higher for T and T tillage treatments in wheat, whereas T tillage treatment 3 4 2 was found to be statistically at par with T . This is because of the presence of higher amount of SOM 1 in T and T . A high and positive correlation between SOC and total N was observed because most of 3 4 the nitrogen present in soil is in organic form.


Author(s):  
Russell L. Steere ◽  
Eric F. Erbe

It has been assumed by many involved in freeze-etch or freeze-fracture studies that it would be useless to etch specimens which were cryoprotected by more than 15% glycerol. We presumed that the amount of cryoprotective material exposed at the surface would serve as a contaminating layer and prevent the visualization of fine details. Recent unexpected freeze-etch results indicated that it would be useful to compare complementary replicas in which one-half of the frozen-fractured specimen would be shadowed and replicated immediately after fracturing whereas the complement would be etched at -98°C for 1 to 10 minutes before being shadowed and replicated.Standard complementary replica holders (Steere, 1973) with hinges removed were used for this study. Specimens consisting of unfixed virus-infected plant tissue infiltrated with 0.05 M phosphate buffer or distilled water were used without cryoprotectant. Some were permitted to settle through gradients to the desired concentrations of different cryoprotectants.


Author(s):  
R. D. Sjolund ◽  
C. Y. Shih

The differentiation of phloem in plant tissue cultures offers a unique opportunity to study the development and structure of sieve elements in a manner that avoids the injury responses associated with the processing of similar elements in intact plants. Short segments of sieve elements formed in tissue cultures can be fixed intact while the longer strands occuring in whole plants must be cut into shorter lengths before processing. While iyuch controversy surrounds the question of phloem function in tissue cultures , sieve elements formed in these cultured cells are structurally similar to those of Intact plants. We are particullarly Interested In the structure of the plasma membrane and the peripheral ER in these cells because of their possible role in the energy-dependent active transport of sucrose into the sieve elements.


Planta Medica ◽  
2013 ◽  
Vol 79 (05) ◽  
Author(s):  
M Mujeeb ◽  
M Amir ◽  
AS Nadeem ◽  
M Aqil ◽  
AK Najmi ◽  
...  

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