unityでuiテキストを更新できません。

前提・実現したいこと

　UIのテキストを更新したいのですが以下の様なエラーメッセージが出て先に進めません。どなたか助けてください。

発生している問題・エラーメッセージ

NullReferenceException: Object reference not set to an instance of an object
Player.updateText (System.String meter) (at Assets/Scripts/Player.cs:68)
Player.Update () (at Assets/Scripts/Player.cs:38)

該当のソースコード

c#
1using System.Collections;
2using System.Collections.Generic;
3using UnityEngine;
4using TMPro;
5
6public class Player : MonoBehaviour
7{
8    public static float meter;
9
10    Rigidbody2D rb2 = new Rigidbody2D();
11
12    float x_mov;
13
14    public TextMeshProUGUI text;
15
16    // Start is called before the first frame update
17    void Start()
18    {
19        rb2 = GetComponent<Rigidbody2D>();
20
21        meter = 0;
22    }
23
24    // Update is called once per frame
25    void Update()
26    {
27        x_mov = Input.GetAxisRaw("Horizontal") * 20;
28        rb2.velocity = new Vector2(x_mov, rb2.velocity.y);
29
30        Debug.Log(Mathf.Floor(this.gameObject.transform.localPosition.y));
31
32        if (rb2.velocity.y > 0)
33        {
34            if (!(meter == Mathf.Floor(this.gameObject.transform.localPosition.y)))
35            {
36                meter = Mathf.Floor(this.gameObject.transform.localPosition.y);
37
38                updateText(meter.ToString() + "m");
39            }
40        }
41
42
43    }
44
45    private void OnCollisionEnter2D(Collision2D collision)
46    {
47        string tag = collision.gameObject.tag;
48
49        if(rb2.velocity.y <= 0)
50        {
51            switch (tag)
52            {
53                case "Floter":
54                    rb2.AddForce(new Vector2(0, 30), ForceMode2D.Impulse);
55                    break;
56
57                case "Anevaino":
58                    rb2.AddForce(new Vector2(0, 60), ForceMode2D.Impulse);
59                    break;
60            }
61        }
62
63
64    }
65
66    void updateText(string meter)
67    {
68        text.text = meter;
69    }
70}
71
72