A method for early non-destructive screening of rooted and surviving cuttings

Abstract

The present application relates to a method for early nondestructive screening of rooting and surviving cutting seedlings, and relates to the field of forest tree breeding. Specifically, the present application finds that the leaf expansion temperature of plant cutting seedlings in the early stage is directly related to survival in the later stage. When the leaf expansion temperature of germinated cutting seedlings in the early stage is lower than the average leaf expansion temperature in the early stage, the survival rate of the germinated cutting seedlings is higher, and the germinated cutting seedlings are retained for further culture. For germinated cutting seedlings with leaf expansion temperature in the early stage higher than the average leaf expansion temperature in the early stage, additional rooting and survival treatment can be performed. Based on this, not only can surviving cutting seedlings be quickly screened, but also difficult-to-root germinated cutting seedlings can be subjected to targeted additional rooting and survival treatment, thereby reducing workload and cost, and improving the overall rooting and survival rate of cuttings.

Description

Technical Field

[0001] This invention relates to the field of forest tree propagation, and in particular to a method for early non-destructive screening of rooted and viable cuttings. Background Technology

[0002] Cuttings are an important method of forest tree propagation. After cutting, the sprouting and leaf development of the cuttings does not guarantee survival; the key is whether roots develop at the base. For species that are difficult to root or at stages where rooting is challenging, the survival rate of cuttings is often low, especially in saline-alkali soils. Because the roots are buried in the soil, it is difficult to observe and count them without affecting growth. Therefore, early and non-destructive screening of rooted and viable cuttings will play a significant role in improving the efficiency of cutting propagation and promoting its automation and industrialization. Summary of the Invention

[0003] This invention provides a method for non-destructively screening rooted and viable cuttings, comprising the following steps: 1) Cuttings of plants; 2) After the cuttings sprout, measure the temperature of the leaves of the sprouted cuttings to obtain the temperature value of the leaves; 3) Calculate the average value of the leaf temperature to obtain the average leaf temperature value; 4) Select budding cuttings that are below the average leaf temperature value.

[0004] In one specific embodiment, the plant is a poplar.

[0005] In one specific implementation, in step 2), the leaf expansion temperature of the germinating cuttings is measured on day 18.

[0006] In one specific implementation, for germinating cuttings grown under stress-free conditions, the germinating cuttings are selected when the leaf expansion temperature is below 27.6 degrees Celsius.

[0007] In one specific embodiment, for germinating cuttings grown under stress conditions of 75 mmol / L NaCl aqueous solution, the germinating cuttings are selected when the leaf expansion temperature is below 28.2 degrees Celsius.

[0008] In one specific implementation, germinating cuttings with temperatures above the average leaf temperature are subjected to root-promoting treatment to increase their survival rate.

[0009] The beneficial effects of this invention are as follows: This invention discovers that the leaf expansion temperature in the early stage of plant cuttings is directly related to the survival rate of the cuttings in the later stage. When the leaf expansion temperature of an individual budding cutting is lower than the average leaf expansion temperature in the early stage of budding cuttings, the rooting survival rate of that individual budding cutting is higher, for example, above 80%, and the individual cutting is retained for further cultivation. For budding cuttings with a leaf expansion temperature higher than the average leaf expansion temperature in the early stage of budding cuttings, additional root-promoting treatment can be performed. Based on this, not only can surviving cuttings be quickly screened, but also targeted additional root-promoting treatment can be performed on budding cuttings that are difficult to root, which reduces workload, lowers costs, and improves the overall rooting survival rate of cuttings. Attached Figure Description

[0010] Figure 1 The germination rates of Examples 1 and 2 are shown.

[0011] Figure 2 The average survival rate of the germinating cuttings in Examples 1 and 2 is shown.

[0012] Figure 3 The average leaf expansion temperature of the germinating cuttings (surviving group and dead group) in Examples 1 and 2 is shown. Detailed Implementation

[0013] The present invention will be further described in detail below through preferred embodiments, but these embodiments do not constitute a limitation thereof.

[0014] Unless otherwise specified, the equipment, consumables, and reagents used in the embodiments of this invention can all be purchased commercially.

[0015] The infrared thermal imager used in this invention is the FLIR ONE Pro infrared thermal imager.

[0016] The substrate for cutting propagation is prepared by mixing peat moss and vermiculite in a 4:1 volume ratio, which provides nutrients and a loose and breathable environment for the germination and rooting of cuttings. Example 1

[0017] Fill seedling trays with propagation substrate and insert the pruned poplar cuttings (15cm long, 0.5-1.0cm thick, with the bottom cut at an angle and the top cut straight) into the substrate. Water thoroughly with tap water until water flows out from the bottom of the tray. Place in a greenhouse for regular cultivation and management. Water normally with tap water thereafter, ensuring no water overflows from the tray. Use 16 poplar cuttings per tray as one replicate, and set up 3 replicates. Example 2

[0018] Fill seedling trays with propagation substrate and insert the pruned poplar cuttings (15cm long, 0.5-1.0cm thick, with the bottom cut at an angle and the top cut straight) into the substrate. For the first watering, thoroughly water the trays with a 75mmol / L NaCl solution (prepared with tap water) until water flows out from the bottom. Place the trays in a greenhouse for routine cultivation and management. Afterward, water normally with tap water, ensuring no water overflows from the trays. Each tray contains 16 poplar cuttings, forming one replicate, with 3 replicates.

[0019] Cuttings were identified as sprouting cuttings when they showed signs of bud break and normal leaf development. The germination rate was calculated, and the temperature of a single unfolded leaf on each sprouted cutting was measured using an infrared thermal imager (if only one leaf was unfolded, the entire leaf was measured; if multiple leaves were unfolded, the leaf with the best development was measured). Both germination rate and leaf temperature measurements were performed 18 days after cutting. When measuring leaf temperature with the infrared thermal imager, the imager was fixed on a tripod and placed 57 cm vertically above the seedling pot for temperature measurement. Eighty-six days after cutting, the rooting and survival of each sprouted cutting was investigated, and the average survival rate of the sprouted cuttings was calculated. Among them, sprouted cuttings that have roots with milky white fine roots and have grown surviving branches and leaves were judged as surviving; sprouted cuttings that have not rooted or whose roots have died and have no surviving branches and leaves were judged as dead. Survival rate = rooted and surviving sprouted cuttings / sprouted cuttings × 100%.

[0020] Figure 1 The germination rates of Examples 1 and 2 are based on... Figure 1 It can be seen that 18 days after the cuttings were taken, the average germination rate of normal culture in Example 1 was 79.17%, and the average germination rate of salt stress culture in Example 2 was 68.75%. There was no significant difference in the germination rate of poplar cuttings between Example 1 and Example 2, indicating that salt stress had no significant effect on the germination rate of poplar cuttings.

[0021] Figure 2 The average survival rate of the germinating cuttings in Examples 1 and 2 is based on... Figure 2 It can be seen that, 86 days after cutting, the average rooting survival rate of the sprouted cuttings cultured under normal conditions in Example 1 was 86.75%, while the average rooting survival rate of the sprouted cuttings cultured under salt stress in Example 2 was 45.35%. The average rooting survival rate of the sprouted cuttings in Example 2 was significantly lower than that in Example 1, indicating that salt stress significantly reduced the survival rate of the sprouted cuttings. Furthermore, not all sprouted cuttings in Examples 2 and 1 survived, indicating that early sprouting does not guarantee later survival.

[0022] For surviving sprouted cuttings, the leaf expansion temperature measured earlier was traced back. The average leaf expansion temperature for each replicate was calculated first, and then the average treatment temperature was calculated based on the average leaf expansion temperatures of the three replicates. For dead sprouted cuttings, the leaf expansion temperature measured earlier was traced back, and the average leaf expansion temperature for each replicate was calculated first, and then the average treatment temperature was calculated based on the average leaf expansion temperatures of the three replicates. A bar chart was created showing the average leaf temperatures of the surviving sprouted cutting group (Example 1), the dead sprouted cutting group (Example 1), the surviving sprouted cutting group (Example 2), and the dead sprouted cutting group (Example 2). Figure 3 As shown.

[0023] The results show that in Example 1, the average early leaf expansion temperature of the surviving germinating cuttings group was 27.49 degrees Celsius, while the average early leaf expansion temperature of the dying germinating cuttings group was 28.50 degrees Celsius, showing a significant temperature difference. In Example 2, the average early leaf expansion temperature of the surviving germinating cuttings group was 27.54 degrees Celsius, while the average early leaf expansion temperature of the dying germinating cuttings group was 28.76 degrees Celsius, also showing a significant temperature difference. This indicates that leaf expansion temperature can be used to screen for germinating cuttings that will survive later in the early stages.

[0024] Furthermore, the average temperature of early leaf expansion of all germinating cuttings in each replicate of Example 1 was calculated, and then the average temperature of early leaf expansion of treated germinating cuttings was calculated based on the average temperature of early leaf expansion of germinating cuttings in three replicates, which was 27.63 degrees Celsius. The average survival rate of germinating cuttings with an early leaf expansion temperature lower than this average temperature was 95.24%. Similarly, the average temperature of early leaf expansion of all germinating cuttings in each replicate of Example 2 was calculated, and then the average temperature of early leaf expansion of treated germinating cuttings was calculated based on the average temperature of early leaf expansion of germinating cuttings in three replicates, which was 28.21 degrees Celsius. The average survival rate of germinating cuttings with an early leaf expansion temperature lower than this average temperature was 81.94%. Therefore, early screening of rooted and viable cuttings can be performed based on the average temperature of early leaf expansion of germinating cuttings.

Claims

1. A method for non-destructively screening rooted and viable cuttings, comprising the following steps: 1) Cuttings of a plant, wherein the plant is a poplar; 2) After the cuttings sprout, the leaf expansion temperature of the sprouted cuttings was measured on the 18th day to obtain the leaf temperature value; 3) Calculate the average value of the leaf expansion temperature to obtain the average leaf temperature value; 4) Select budding cuttings that are below the average leaf temperature value.

2. The method according to claim 1, characterized in that, For germinating cuttings grown under stress-free conditions, the germinating cuttings are selected when the leaf expansion temperature is below 27.6 degrees Celsius.

3. The method according to claim 1, characterized in that, For germinating cuttings grown under stress with 75 mmol / L NaCl aqueous solution, the germinating cuttings were selected when the leaf expansion temperature was below 28.2 degrees Celsius.

4. The method according to claim 1, characterized in that, For individual budding cuttings with temperatures higher than the average leaf temperature, root-promoting treatment is applied to increase their survival rate.

Images