Abstract:
A device for collecting plant samples includes a punch and die mechanism for taking leaf plugs from plants. The punch itself includes a punch rod coaxially mounted inside a punch tube. In use, the punch tube has a distal end with two, diametrically opposed projections that interact with the formed aperture to cut a plug from a plant leaf. The punch rod then follows to remove a cut leaf plug from the formed aperture. Also included is a hydraulic subsystem for periodically delivering liquid on the punch and die mechanism to prevent plant debris from clogging the device.

Description:
FIELD OF THE INVENTION 
     The present invention pertains generally to sampling systems. More particularly, the present invention pertains to systems that provide for marker assisted breeding and the quality control of agricultural plants. The present invention is particularly, but not exclusively useful for obtaining genetic markers from a vast number of plants that will help select plants with a desired genotype and/or phenotype. 
     BACKGROUND OF THE INVENTION 
     It is well known that genetic markers can be obtained from DNA and used for a variety of purposes. For example, in the field of agriculture, the DNA that is taken from plant material will yield genetic markers that can be used in marker assisted breeding. In this process, DNA sequences are used to follow desirable agronomic traits in the process of plant breeding. 
     For marker assisted breeding, seeds of plants with a desired trait are planted either in a greenhouse, in a field or in a hydroponic system. Plant tissue (for example, leaf) is then harvested from the plants for preparation of DNA once sufficient tissue can be removed from the plants without compromising their viability. Thus, genomic DNA is isolated for further processing to find specific genetic characteristics. In the subsequent processing, these characteristics are linked to traits of interest and are thereby used to predict the presence or absence of the traits of interest in the sampled plants. 
     As a practical matter, the identification of plants involves complicated procedures that are difficult, if not impossible, to accomplish on-site in the field. The situation becomes further complicated when a large number of plants are involved, such as in a commercial agricultural operation where thousands, or tens of thousands, of different plants are being cultivated in the same field. In such operations, the ability to subsequently identify a particular plant may be of crucial importance. Further, the samples must be easily collected and efficiently presented for processing. Also, whatever device is used to collect the samples of plant material must be capable of reliable operation through many repetitive cycles, for prolonged periods of time. For instance, samples may need to be taken from several thousand different plants. According to the present invention, these samples can be taken from different plant tissue, including but not limited to stem, root, or seed tissue. Preferably, these samples can be taken from the leaves or cotyledons of the plants. 
     A particularly effective mechanism for collecting samples of plant material is the rather well known punch and die. Such a mechanism, however, is not problem-free. For one, the punch and die must consistently remove samples from the plants without fouling the mechanism. This requires a clean cut of the sample, and an effective separation of the cut sample from the plant. For another, any clogging or contamination of the punch mechanism that might result from the accumulation of solid and liquid debris must be avoided or, at least, minimized. On this last point, it has been determined that the punch clogging phenomenon is highly dependent on the ambient temperature and the relative humidity. Within these parameters, a warm, dry ambient condition has been determined to be most conducive to punch clogging. Tests have shown, however, that this problem can be effectively alleviated by periodically applying water on the punch and die mechanism. 
     In light of the above, it is an object of the present invention to provide a device for collecting samples of material from plants that consistently cuts and removes samples from a plant for further processing. Another object of the present invention is to achieve sustained operation of a device for collecting samples of material from plants by effectively preventing any clogging of the device by solid and liquid debris. Still another object of the present invention is to provide a device for collecting samples of material from plants that is easy to use, is relatively simple to manufacture, and is comparatively cost effective. 
     SUMMARY OF THE INVENTION 
     A device for collecting samples of material from plants includes a punch and die mechanism that is mounted on a base member. The punch portion of this mechanism includes a punch tube in combination with a punch rod. In detail, the punch tube is elongated and cylindrical shaped. It also has a distal end that is formed with two cutting projections. Specifically, the cutting projections extend axially in a distal direction from the distal end of the punch tube. In combination, the punch rod is coaxially positioned for reciprocal movement inside the lumen of the punch tube. The formed aperture portion of the mechanism is annular shaped and is mounted on the base member to interact with the punch portion. 
     In their combination, the punch tube and the punch rod require a link rod that holds them in predetermined relationships. For this purpose, the wall of the punch tube is formed with a pair of diametrically opposed holes. On the other hand, the punch rod is formed with a single, axially oriented, oblong hole. The link rod is then inserted through the pair of axially opposed holes in the punch tube, and also through the oblong hole of the punch rod. Thus, axial movements of the punch rod in the lumen of the punch tube are limited by the length of its oblong hole. More specifically, within the lumen of the punch tube, the punch rod can move between a first position and a second position. In the first position, the distal end of the punch rod is proximal to the distal end of the punch tube. In the second position, the distal end of the punch rod is distal to the distal end of the punch tube. 
     As intended for the present invention, movements of the punch tube and punch rod are initiated by a drive mechanism. Structurally, this drive mechanism is mounted on the base member and involves the interaction of an actuator, a drive rod, a cam block and a yoke. In detail, the cam block is relatively compact in structure and is mounted for reciprocal movement on the base member. It is formed with a slot. The yoke, on the other hand, is an elongated member having a first end and a second end with a midpoint therebetween. The yoke also includes a pin that is affixed to its second end. With this structure, the yoke is pivotally mounted on the base member at its midpoint. In this arrangement, the first end of the yoke is engaged with the link rod that holds the punch rod in the lumen of the punch tube, and the pin at the second end of the yoke is positioned in the slot of the cam block. 
     In an operation of the device of the present invention, the actuator moves the drive rod. In turn, the drive rod moves the cam block. As the cam block moves, the pin on the yoke is guided along the slot in the cam block to rotate the yoke. With a rotation of the yoke, the yoke urges against the link rod and this causes the punch tube and punch rod combination to move relative to the formed aperture. More specifically, the punch tube is moved between first and second locations. During this movement of the punch tube, the punch rod moves back and forth between distal and proximal positions in the lumen of the punch tube. In its first (retracted) location, the distal end of the punch tube is at a distance from the formed aperture to create a gap between them for receiving a leaf therein. Also, the punch rod is at its distal position in the lumen of the punch tube. In its second location, the distal end of the punch tube is in contact with the formed aperture. As the punch tube moves between these locations, the projections on the distal end of the punch tube interact with the formed aperture to cut a leaf plug from the leaf in the gap. Also, due to its inertia, the punch rod is at its proximal position in the lumen of the punch tube during this movement of the punch tube. After the leaf plug has been cut (i.e. the punch tube is in its second location), the punch tube stops while the movement of the punch rod continues. Specifically, the momentum of the punch rod initiates a movement of the punch rod relative to the punch tube, causing the punch rod to move from its proximal position to its distal position. This movement of the punch rod then removes the cut leaf plug from the formed aperture for its collection. 
     An additional feature of the device of the present invention is an apparatus for irrigating the punch and die mechanism. Specifically, this irrigating apparatus includes a source of water (or a solvent, e.g. alcohol) and a transfer tube. The transfer tube has a first end that is connected in fluid communication with the water source, and it has a second end that is positioned to selectively deliver pressurized water onto the respective distal ends of the punch tube and punch rod, as well as onto the formed aperture. Further, this selective delivering can be periodically accomplished, as desired (e.g. after every 50 leaf plug cuts). The purpose here is to prevent clogging of the device with leaf debris. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which: 
         FIG. 1  is a perspective view of the device of the present invention; 
         FIG. 2  is a cross section view of the punch mechanism of the device as seen along the line  2 - 2  in  FIG. 1 ; 
         FIG. 3  is a cross section view of the punch mechanism of the device as seen along the line  3 - 3  in  FIG. 1 ; 
         FIG. 4A  is a cross section view of the punch activation mechanism of the device as seen along the line  4 - 4  in  FIG. 1 , at the beginning of a punch cycle; 
         FIG. 4B  is a cross section view of the punch activation mechanism of the device as seen along the line  4 - 4  in  FIG. 1 , during a punch cycle; 
         FIG. 4C  is a cross section view of the punch activation mechanism of the device as seen along the line  4 - 4  in  FIG. 1 , at the end of a punch cycle; 
         FIG. 5A  corresponds to  FIG. 4A  and is an enlarged view showing the punch rod in its distal position; 
         FIG. 5B  corresponds to  FIG. 4B  and is an enlarged view showing the punch rod in its proximal position; and 
         FIG. 5C  corresponds to  FIG. 4C  and is an enlarged view showing the punch rod in its distal position. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring initially to  FIG. 1 , a device for collecting samples of plant material in accordance with the present invention is shown and is generally designated  10 . As shown, in one embodiment of the invention the device  10  includes a leaf sampler  12  that has a punch mechanism  14 , and a formed aperture  16  at its forward end. Shown in phantom in  FIG. 1  is an actuator  18  that is mounted inside the leaf sampler  12 . Also shown in phantom is a valve  20  that is mounted with the actuator  18  inside leaf sampler  12 .  FIG. 1  further shows that the leaf sampler  12  includes a keypad  22  that can be manipulated by a user (not shown) to operate the actuator  18  and the valve  20  of the leaf sampler  12 . 
     Still referring to  FIG. 1 , it will be further seen that the device  10  includes a power pack  24  and a source  26  of pressurized liquid. Both of these components, the power pack  24  and the liquid source  26 , are operatively connected to the leaf sampler  12  via a cable  28  and a connector  30 . As intended for the present invention, these connections allow a user to independently and separately accomplish two separate tasks for the leaf sampler  12 . For one, power from the power pack  24  can be used to activate the actuator  18  that, in turn, moves the punch mechanism  14  of the leaf sampler  12 . For another, pressurized liquid from the liquid source  26  can be provided for cleaning the punch mechanism  14 . These tasks can be accomplished simply by manipulation of the keypad  22 . 
     Turning now to  FIGS. 2 and 3 , the punch mechanism  14  is shown to include a punch tube  32  in combination with a punch rod  34 . In this combination, the punch tube  32  is an elongated hollow tube that is formed with a lumen. On the other hand, the punch rod  34  is substantially solid and is disposed in the lumen of the punch tube  32  for back and forth axial movements along the length of the punch tube  32 . Further, as shown in both  FIG. 2  and  FIG. 3 , the punch rod  34  is formed with an oblong hole  36  that is located approximately midway between the ends of the punch rod  34 . Also, the distal (lower) end of the punch tube  32  is formed with a pair of diametrically opposed projections  38   a  and  38   b  (see  FIG. 2 ). For purposes of the present invention, the projections  38   a  and  38   b  are formed using a cylindrical drill (cutter) to engage the punch tube  32  at a right angle to its longitudinal axis. 
     As shown in  FIGS. 2 and 3 , the punch rod  34  is supported in the lumen of punch tube  32  by a link rod  40 . This link rod  40  is rigidly affixed to the punch tube  32  and extends diametrically across its lumen. The link rod  40  also passes through the oblong hole  36  in the punch rod  34 . With this structural combination, limited axial movements of the punch rod  34  in the lumen of punch tube  32  are made possible by the interaction of oblong hole  36  in the punch rod  34  with the link rod  40 . Specifically, these limited movements of punch rod  34  relative to punch tube  32  are confined to the distance  42  shown in  FIG. 2 . 
       FIG. 4A  indicates the leaf sampler  12  includes a base member  44  on which the punch mechanism  14  and the formed aperture  16  are mounted. Also, a cam block  46  is mounted on the base member  44  and is attached to a drive rod  48 . In turn, the drive rod  48  is connected to the actuator  18  (see  FIG. 1 ). With this connection, the actuator  18  is able to move the cam block  46  back and forth on the base member  44  in the direction of arrows  50 .  FIG. 4A  also indicates that a yoke  52  is mounted on the base member  44  for rotation about a pivot point  54 . Further, as shown, a pin  56  is affixed to one end of the yoke  52  and it (the pin  56 ) is positioned in a slot  58  that is formed on the cam block  46 . The end of yoke  52  that is opposite from the pin  56  is attached directly to the link rod  40  and indirectly to the punch tube  32  of punch mechanism  14  via link rod  40 . 
     Still referring to  FIG. 4A , it is seen that the punch mechanism  14  is held in position on the base member  44  by an upper guide  60  and a lower guide  62 . Together, the guides  60  and  62  require the punch mechanism  14  travel on a linear path toward, and away from, the formed aperture  16 .  FIG. 4A  also shows that the base member  44  is formed with a fluid pathway  64  that interconnects a nozzle  66  in fluid communication with the valve  20  (see  FIG. 1 ). With this connection, a fluid pathway  64  is established between the pressurized liquid source  26  and the nozzle  66  that can be effectively controlled by operation of the valve  20 .  FIG. 4A  further shows that the base member  44  is shaped to establish a gap  68  that is located on the base member  44  between the punch mechanism  14  and the formed aperture  16 . 
     Operation 
     The operation of the device  10  of the present invention will be best appreciated with collective reference to  FIGS. 4A ,  4 B and  4 C and with respective reference to  FIGS. 5A ,  5 B and  5 C. With this collective reference, an operational cycle of the device  10  begins with the leaf sampler  12  configured as shown in  FIG. 4A  (see also  FIG. 5A ). A leaf  70  (see  FIG. 4B ) can then be inserted into the gap  68 . With a leaf  70  so positioned in the gap  68 , the user (not shown) manipulates the keypad  22  to activate the actuator  18 . This causes the actuator  18  to move the drive rod  48 , and to thereby move the cam block  46  sequentially through the positions shown respectively in  FIGS. 4A ,  4 B and  4 C. Consequently, the yoke  52  and punch mechanism  14  are also sequentially moved through the positions shown respectively in  FIGS. 4A ,  4 B and  4 C (see also  FIGS. 5A ,  5 B and  5 C). 
     An aspect of the present invention can be appreciated by comparing the relative positions of the punch tube  32  and punch rod  34  as they move through the configurations shown in  FIGS. 4A ,  4 B and  4 C (see also corresponding  FIGS. 5A ,  5 B and  5 C). First compare  FIG. 4A  with  FIG. 4B . In the cycle start position ( FIG. 4A ), the punch rod  34  effectively hangs at a distal position in the lumen of punch tube  32  from the link rod  40  ( FIG. 5A ). With the activation of an operational cycle, however, the cam block  46  and yoke  52  combine to mechanically drive the link rod  40  in a direction toward the formed aperture  16  (see  FIG. 4B ). Recall, the link rod  40  is connected directly to the punch tube  32 . The link rod  40 , however, is also located in the oblong hole  36  in punch rod  34 . Thus, due to a consequent rapid acceleration to the link rod  40 , the link rod  40  effectively drives both the punch tube  32  and the punch rod  34  toward the formed aperture  16 . The inertia of punch rod  34 , however, causes it to move to a proximal position in the lumen of punch tube  32  (see the location of link rod  40  in oblong hole  36  of the punch rod  34  in  FIGS. 4B and 5B ). During this movement, the exposed projections  38   a  and  38   b  on the punch tube  32  cut a leaf plug  72  from the leaf  70 . 
     Now consider  FIG. 4B  with  FIG. 4C . As shown in  FIG. 4B , while the punch tube  32  is cutting a leaf plug  72  from leaf  70 , the punch rod  34  is withdrawn to its proximal position in the lumen of the punch tube  32  (see  FIG. 5B ). As implied above, this withdrawal of punch rod  34  into the lumen of punch tube  32  results from the inertia of punch rod  34 . When the punch tube  32  contacts the abutment  74  below formed aperture  16 , however, this changes. Specifically, as best appreciated with reference to  FIG. 4C , although the abutment  74  stops the punch tube  32 , it does not stop the punch rod  34  at the same time. Instead, due to its momentum, the punch rod  34  continues to move through the distance  42  ( FIG. 2 ) and return to its distal position (see  FIG. 5C ). This additional movement effectively clears the leaf plug  72  from formed aperture  16  and deposits the leaf plug  72  into the sample container  76  for further processing. As a final step in an operational cycle of the leaf sampler  12 , it returns to the configuration shown in  FIG. 4A . 
     In the illustrated embodiment, inertia and momentum are used to provide the movement of the punch rod  34  relative to the punch tube  32 . Alternatively, movement of the punch rod  34  relative to the punch tube  32  could be mechanically actuated. 
     As intended for the present invention, the punch mechanism  14  needs to be irrigated to remove solid and liquid leaf debris. Specifically, the punch mechanism  14  may become clogged by leaf debris that wedges between the punch rod  34  and the aperture  16 . Also, leaf debris may adhere to the punch mechanism  14  and be carried by the punch mechanism  14  up from the gap  68  and into the base member  44 . In either case, the leaf debris may be removed by manipulating the keypad  22 . Thus, whenever an appropriate entry is made on keypad  22 , the valve  20  releases liquid from the pressurized liquid source  26 . This liquid then progresses through the pathway  64 , and through the nozzle  66 , onto the punch mechanism  14 . Alternatively, this irrigation can be accomplished periodically, at timed intervals, or constantly. However applied, the liquid irrigates the punch mechanism  14  in the vicinity of the projections  38   a  and  38   b  to remove solid and liquid leaf debris that would otherwise clog the punch mechanism  14 . Preferably, the punch mechanism  14  is irrigated after approximately fifty leaf plugs  72  have been collected. In certain embodiments, the liquid may be water or solvent. Alternatively, the liquid may include anti-biotic, anti-viral, or anti-pathogenic compounds to reduce cross contamination by the punch mechanism  14 . 
     While the particular Device for Sampling Plant Material as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.