Cuttings are one of the widely used methods of raising seedlings for flowers and fruit trees. They include hardwood cuttings and softwood cuttings. The soft-twig cuttings that are introduced for everyone now are the newly-growing shoots that grow strong and begin to lignify during the plant growth period. They are also called tender shoot cuttings or green branch cuttings. Soft branch cutting seedlings should pay attention to the following points:
1. Select the plant species suitable for softwood cutting
Soft branch cuttings are generally suitable for varieties that are prone to produce adventitious roots, such as chrysanthemum, chrysanthemum, hippophae, marigold, calendula, periwinkle, zinnia, jasmine, hibiscus, hibiscus, geranium, a bunch of red, cactus, pomegranate , bergamot, grapes and so on.
2. Suitable for cutting
Soft branch cuttings, in addition to the winter and summer seasons, require special circumstances. There are no special requirements during the growing seasons of other seasons, and they can be carried out at any time. It is most appropriate to complete the shoot from the end of each shoot to the next shoot; if in the greenhouse It can be carried out all year round if it is cut in a protective field such as a greenhouse.
3. Select the cuttings
To cut the thick growing branches on the fine mother plants, remove all the buds from the cut branches. Cut the young part of the top, use the middle and lower section to make the cuttings, cut it according to a length of 8 to 12 centimeters, cut at the top, and cut the bottom to form a horse-shaped slope, and each cutting strip retains 2 to 4 full-filled axillary buds. Leave 1-2 leaves at the top and cut off all other leaves; if it is a large leaf-shaped variety, keep 1/3 to 1/2 of the leaves when clipping to reduce evaporation.
After the cuttings are cut, the base is soaked in the rooting powder for 2 to 3 minutes. This prevents the base of the cuttings from rot, promotes rooting, and improves the survival rate.
4. Do a good job cutting
Cutting seedbeds should be selected for organic-rich, loose fertile, low groundwater level, well-performing land, fine soil preparation; cuttings to be collected at any time, trim at any time, cutting at any time; to be selected in the morning or evening cutting; Punch the soil, insert about 2/3 of the soil, reveal 1~2 buds at the top; compact the soil after plugging in.
5. Post-cut management
The key to improving the survival rate of cuttings is to improve management after cutting out. Firstly, moisturizing and promoting roots should be used. After pouring, the water should be poured once. Afterwards, according to the degree of dryness and wetness of the seedbed soil, timely watering should be carried out in a timely manner. The method is to keep the soil moisture at about 80%. When the air is dry, the leaf is sprayed with water, so that the relative humidity of the air reaches about 80%. If the watering is too much, the humidity is too high, and the soil is stained with water, it will easily cause local rot of the cuttings. If the soil is dry and lack of water, the cuttings will easily produce physiological water loss, and it will be difficult to root, and it will easily lead to death. Followed by sun protection against sun exposure. If in the summer cuttings, the evaporation of the water under high temperature in the hot sun is large, the seedbed should be put on a shed or cover the shade net to prevent the sun exposure, ensure the temperature and humidity, keep the temperature within 30C, and maintain good temperature and humidity in the seedbed. To ensure the transparency of the air, to better promote the rooting of the cuttings.
Ventilator block diagram
One. Main mechanical ventilation modes
(1) Intermittent Positive Pressure Ventilation (IPPV): positive pressure in the inspiratory phase and zero pressure in the expiratory phase. 1. Working principle: The ventilator generates positive pressure in the inspiratory phase and presses the gas into the lungs. After the pressure rises to a certain level or the inhaled volume reaches a certain level, the ventilator stops supplying air, the exhalation valve opens, and the patient's thorax Passive collapse of the lungs and exhalation. 2. Clinical application: Various patients with respiratory failure mainly based on ventilation function, such as COPD.
(2) Intermittent positive and negative pressure ventilation (IPNPV): the inspiratory phase is positive pressure and the expiratory phase is negative pressure. 1. How it works: The ventilator works both in the inspiratory and exhaled phases. 2. Clinical application: Expiratory negative pressure can cause alveolar collapse and cause iatrogenic atelectasis.
(3) Continuous positive pressure airway ventilation (CPAP): Refers to the patient's spontaneous breathing and artificial positive airway pressure during the entire respiratory cycle. 1. Working principle: Inspiratory phase gives continuous positive pressure air flow, and exhalation phase also gives a certain resistance, so that the airway pressure of inhalation and exhalation phases are higher than atmospheric pressure. 2. Advantages: The continuous positive pressure airflow during inhalation is greater than the inspiratory airflow, which saves the patient's inhalation effort, increases FRC, and prevents the collapse of the airway and alveoli. Can be used for exercise before going offline. 3. Disadvantages: great interference to circulation, large pressure injury of lung tissue.
(4) Intermittent command ventilation and synchronized intermittent command ventilation (IMV / SIMV) IMV: There is no synchronization device, the ventilator air supply does not require the patient's spontaneous breathing trigger, and the time of each air supply in the breathing cycle is not constant. 2. SIMV: There is a synchronization device. The ventilator gives the patient a commanded breath according to the pre-designed breathing parameters every minute. The patient can breathe spontaneously without being affected by the ventilator. 3. Advantages: It exerts its ability to regulate breathing while offline; it has less influence on circulation and lungs than IPPV; it reduces the use of shock medicine to a certain extent. 4. Application: It is generally considered to be used when off-line. When R <5 times / min, it still maintains a good oxygenation state. You can consider off-line. Generally, PSV is added to avoid respiratory muscle fatigue.
(5) Mandatory ventilation per minute (MMV) When spontaneous breathing> preset minute ventilation, the ventilator does not command ventilation, but only provides a continuous positive pressure. 2. When spontaneous breathing is less than the preset minute ventilation volume, the ventilator performs command ventilation to increase the minute ventilation volume to reach the preset level.
(6) Pressure Support Ventilation (PSV) Definition: Under the prerequisite of spontaneous breathing, each inhalation receives a certain level of pressure support, increasing the patient's inhalation depth and inhalation volume. 2. How it works: The inspiratory pressure begins with the patient's inspiratory action, and ends when the inspiratory flow rate decreases to a certain level or the patient attempts to exhale hard. Compared with IPPV, the pressure it supports is constant, and it is adjusted by the feedback of the inspiratory flow rate. Compared with SIMV, it can get pressure support for each inhalation, but the level of support can be set according to different needs. 3. Application: SIMV + PSV: used for preparation before off-line, can reduce breathing work and oxygen consumption Indications: Exercise the ventilator; prepare before going offline; the ventilator is weak due to various reasons; severe flail chest causes abnormal breathing. 5. Note: Generally not used alone, it will produce insufficient or excessive ventilation.
(7) Volume Supported Ventilation (VSV): Each breath is triggered by the patient's spontaneous breathing. The patient can also breathe without any support and can reach the expected TV and MV levels. The ventilator will allow the patient to be truly autonomous Breathing also applies to preparations before going offline.
(8) Capacity control of pressure regulation
(IX) Biphasic or bilevel positive pressure ventilation How it works: P1 is equivalent to inspiratory pressure, P2 is equivalent to breathing pressure, T1 is equivalent to inspiratory time, and T2 is equivalent to exhalation time. 2. Clinical application: (1) When P1 = inspiratory pressure, T1 = inspiratory time, P2 = 0 or PEEP, T2 = expiratory time, which is equivalent to IPPV. (2) When P1 = PEEP, T1 = infinity, P2 = 0, T2 = O, which is equivalent to CPAP. (3) When P1 = inspiratory pressure, T1 = inspiratory time, P2-0 or PEEP, T2 = desired controlled inhalation cycle, equivalent to SIMV.
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