2.2. Experimental design
A greenhouse experiment utilizing a full factorial randomized
block design was implemented. It included two soil types, three
inocula and two ecotypes of two different species of plants. The
entire experiment was replicated ten times for a total of 240 plants,
which were seeded directly into DeepotsTM (Stewe & Sons). Pots
were model D40, type H, which were 25cm deep, with a diameter
of 6.4cm and a total volume of 656 ml.
The two soil types were mine soil (MS) and non-mine soil (NS).
Mine soil was composed of coal tailings from the mine mixed with
sand in a 50:50 ratio. Non-mine soil was composed of low-nutrient
clay soil mixed with sand in a 50:50 ratio. Both media were passed
through a 1-in. wire mesh to remove large clumps and turned in a
cement mixer to assure thorough mixing of sand and soil/coal. The
media were steam pasteurized for three days in a flatbed steamer.
This method had previously been tested and verified by our laboratory
as sufficient to kill AM fungi.
Fungal treatments were fungi collected from the mine (FM),
fungi collected from the control site or non-mine fungi (FN), and
a microbial wash (F0). Plant ecotypes for each species were designated
mine plants (PM) and non-mine plants (PN). Five blocks were
established, each consisting of two full replicates of the experiment
and randomized within each block, for a total of 240 pots and 10
complete replicates of the experiment. Analysis of variance found
no block effects.
Plants were grown for four months in a greenhouse, with a
sixteen-hour day. Each pot received 50 ml of Peterson’s 15-0-15
fertilizer, diluted to 5.5 g/L, on a weekly basis. Plants were watered
daily. At harvest, plants were cut even with the soil, then dried for
3 days in a 60 ◦C oven and weighed for above-ground biomass. The
remaining roots and soil were removed intact from the deepots,
weighed, and then divided roughly in half lengthwise. Each half was
then weighed. Roots were extracted from one half of the divided
sample, dried for three days in a 60 ◦C oven and weighed again.
Total root biomass was extrapolated based on the fraction of soil.
The other half of the roots and soil were reserved as inoculum for a
subsequent experiment. Root samples from every pot were stained
and checked for absence or presence of AM fungi. All inoculated
plants were found to harbor AM fungi and none of the F0 controls
were colonized by AM fungi.
Inoculum potential was evaluated using sorghum that was
planted in each inoculum type (FM and FN). Two dilutions were
prepared, pure inoculum and inoculum diluted 1:10 by volume
with sterile sand. The latter represents the same dilution level used
for the experiment. Five replicates of each treatment were planted
and harvested after 40 days. Roots were stained in trypan blue and
mounted on slides. Arbuscules, vesicles and hyphae were counted
and scored per McGonigle et al. (1990). No significant differences
were found between the two inocula, based on a two-way analysis
of variance.
2.2. ทดลองออกแบบเรือนกระจกเป็นการทดลองใช้แฟกทอเรียลเต็ม randomizedออกแบบบล็อกถูกนำมาใช้ ได้รวมดินสองชนิด 3inocula และ ecotypes สองของพืชสองชนิดที่แตกต่างกัน ที่การทดลองทั้งหมดถูกจำลองแบบสิบครั้งสำหรับพืช 240ซึ่งถูก seeded ลง DeepotsTM (Stewe และบุตร) หม้อมีรุ่น D40 ชนิด H ซึ่งได้ลึก กับมีเส้นผ่าศูนย์กลาง 25 ซม.6.4 ซม.และปริมาตรรวมของมล 656สองดินชนิดมีเหมืองดิน (MS) และดินไม่ใช่ระเบิด (NS)ดินเหมืองประกอบด้วย tailings ถ่านหินจากเหมืองที่ผสมกับทรายในอัตราคนละครึ่ง ดินระเบิดไม่ได้ประกอบด้วยธาตุอาหารต่ำดินดินเหนียวผสมกับทรายในอัตราคนละครึ่ง สื่อทั้งสองถูกส่งผ่านผ่านตาข่ายลวด 1 ค่ะเอากระจุกใหญ่ และเกลียดในการเครื่องผสมปูนซีเมนต์เพื่อให้มั่นใจอย่างละเอียดผสมทรายและดิน/ถ่านหิน ที่สื่อ pasteurized สามวันในนึ่งแท่นไอน้ำได้วิธีการนี้ก่อนหน้านี้ได้ถูกทดสอบ และตรวจสอบ โดยห้องปฏิบัติการของเราเป็นเพียงพอที่จะฆ่าเป็นเชื้อรารักษาเชื้อราได้รวบรวมจากเหมือง (FM), เชื้อรารวบรวมจากเว็บไซต์ควบคุมหรือเชื้อราไม่ใช่เหมือง (FN), เชื้อรา และล้างจุลินทรีย์การ (F0) โรงงาน ecotypes สำหรับแต่ละชนิดถูกกำหนดเหมืองโรงงาน (PM) และพืชไม่เหมือง (PN) บล็อกห้าได้ก่อตั้งขึ้น ซึ่งทั้งสองเหมือนกับการทดลองและ randomized ภายในแต่ละบล็อค จำนวน 240 หม้อและ 10ทำเหมือนกับการทดลอง วิเคราะห์ผลต่างของพบno block effects.Plants were grown for four months in a greenhouse, with asixteen-hour day. Each pot received 50 ml of Peterson’s 15-0-15fertilizer, diluted to 5.5 g/L, on a weekly basis. Plants were watereddaily. At harvest, plants were cut even with the soil, then dried for3 days in a 60 ◦C oven and weighed for above-ground biomass. Theremaining roots and soil were removed intact from the deepots,weighed, and then divided roughly in half lengthwise. Each half wasthen weighed. Roots were extracted from one half of the dividedsample, dried for three days in a 60 ◦C oven and weighed again.Total root biomass was extrapolated based on the fraction of soil.The other half of the roots and soil were reserved as inoculum for asubsequent experiment. Root samples from every pot were stainedand checked for absence or presence of AM fungi. All inoculatedplants were found to harbor AM fungi and none of the F0 controlswere colonized by AM fungi.Inoculum potential was evaluated using sorghum that wasplanted in each inoculum type (FM and FN). Two dilutions wereprepared, pure inoculum and inoculum diluted 1:10 by volumewith sterile sand. The latter represents the same dilution level usedfor the experiment. Five replicates of each treatment were plantedand harvested after 40 days. Roots were stained in trypan blue andmounted on slides. Arbuscules, vesicles and hyphae were countedand scored per McGonigle et al. (1990). No significant differenceswere found between the two inocula, based on a two-way analysisof variance.
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